A. Noman, M. Tusar, K. Uddin, Faruk Uddin, S. Paul, M.M. Rahman
Unmanned Underwater Vehicle (UUV) is vehicle that is controlled by human or automatically and operated underwater for executing different task. For effective maneuverability, the hydro dynamic performance of the UUV has to be evaluated or predicted before employed in the workspace. CFD software was used in this study. The model was designed in CAD software. As the UUV was symmetric about XY plane axis, so half of the UUV body was simulated. It is seen that negative lift is present for all velocity at zero angle of attack. This is a great finding of the study. This is due to conning tower which is located upon the top surface. As the angle of attack change from negative to more positive value, negative lift shifts more quickly to positive value for higher velocity. At higher velocity Lift coefficient does not change so much with velocity. Same amount to drag experience by the UUV for different diving angle. A lot of variation was found with velocity as expected, since drag is proportional to the square of velocity. CD is almost same for all diving angle for different velocity, except for lowest velocity 0.2m/s. Further investigation is needed for this large variation. From lift curve it is seen that for 0.2m/s and 0.4m/s velocity almost always creating negative lift for all diving angle. But for 0.6m/s lift was positive. A considerable difference captured in CL at 0.2m/s and 1m/s for zero diving angle. This is an important finding of the study. Other Cl are not much differing for different diving angle. Pitching moment does not vary with diving angle for constant velocity. But considerable change found in velocity difference as expected. Pitching moment coefficients does not change above 5° diving angle for different velocity. But at low diving angle up to 5° the change is considerable.Unmanned Underwater Vehicle (UUV) is vehicle that is controlled by human or automatically and operated underwater for executing different task. For effective maneuverability, the hydro dynamic performance of the UUV has to be evaluated or predicted before employed in the workspace. CFD software was used in this study. The model was designed in CAD software. As the UUV was symmetric about XY plane axis, so half of the UUV body was simulated. It is seen that negative lift is present for all velocity at zero angle of attack. This is a great finding of the study. This is due to conning tower which is located upon the top surface. As the angle of attack change from negative to more positive value, negative lift shifts more quickly to positive value for higher velocity. At higher velocity Lift coefficient does not change so much with velocity. Same amount to drag experience by the UUV for different diving angle. A lot of variation was found with velocity as expected, since drag is proportional to the square of ...
{"title":"Performance analysis of an unmanned under water vehicle using CFD technique","authors":"A. Noman, M. Tusar, K. Uddin, Faruk Uddin, S. Paul, M.M. Rahman","doi":"10.1063/1.5115886","DOIUrl":"https://doi.org/10.1063/1.5115886","url":null,"abstract":"Unmanned Underwater Vehicle (UUV) is vehicle that is controlled by human or automatically and operated underwater for executing different task. For effective maneuverability, the hydro dynamic performance of the UUV has to be evaluated or predicted before employed in the workspace. CFD software was used in this study. The model was designed in CAD software. As the UUV was symmetric about XY plane axis, so half of the UUV body was simulated. It is seen that negative lift is present for all velocity at zero angle of attack. This is a great finding of the study. This is due to conning tower which is located upon the top surface. As the angle of attack change from negative to more positive value, negative lift shifts more quickly to positive value for higher velocity. At higher velocity Lift coefficient does not change so much with velocity. Same amount to drag experience by the UUV for different diving angle. A lot of variation was found with velocity as expected, since drag is proportional to the square of velocity. CD is almost same for all diving angle for different velocity, except for lowest velocity 0.2m/s. Further investigation is needed for this large variation. From lift curve it is seen that for 0.2m/s and 0.4m/s velocity almost always creating negative lift for all diving angle. But for 0.6m/s lift was positive. A considerable difference captured in CL at 0.2m/s and 1m/s for zero diving angle. This is an important finding of the study. Other Cl are not much differing for different diving angle. Pitching moment does not vary with diving angle for constant velocity. But considerable change found in velocity difference as expected. Pitching moment coefficients does not change above 5° diving angle for different velocity. But at low diving angle up to 5° the change is considerable.Unmanned Underwater Vehicle (UUV) is vehicle that is controlled by human or automatically and operated underwater for executing different task. For effective maneuverability, the hydro dynamic performance of the UUV has to be evaluated or predicted before employed in the workspace. CFD software was used in this study. The model was designed in CAD software. As the UUV was symmetric about XY plane axis, so half of the UUV body was simulated. It is seen that negative lift is present for all velocity at zero angle of attack. This is a great finding of the study. This is due to conning tower which is located upon the top surface. As the angle of attack change from negative to more positive value, negative lift shifts more quickly to positive value for higher velocity. At higher velocity Lift coefficient does not change so much with velocity. Same amount to drag experience by the UUV for different diving angle. A lot of variation was found with velocity as expected, since drag is proportional to the square of ...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121881412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Islam, Shajedul Hoque Thakur, Abrar Ul Karim, S. Saha, M. Hasan
Two-dimensional, laminar, steady mixed convection heat transfer in a long horizontal channel has been investigated numerically with flow modulation through periodically distributed heat conducting rotating cylinders. The upper wall of the channel is maintained at constant low temperature and the lower wall is maintained at constant high temperature. A series of heat conducting rotating cylinders is placed periodically along the centerline of the channel with a spacing between two successive cylinders being equal to the height of the channel. The mathematical model of the present problem is governed by two-dimensional continuity, momentum and energy equations. The governing equations are then transformed to non-dimensional forms that are solved by using Galerkin finite element method with triangular discretization system. Water, air and liquid Gallium are considered as the working fluids. Numerical simulation is performed for case of pure mixed convection heat transfer characterized by a Richardson number of unity. Parametric simulation is carried out for a wide range of Reynolds numbers (1 ≤ Re ≤500) based on the dynamic condition of the rotating cylinder. Numerical results are presented and analyzed in terms of the distribution of streamline and isotherm patterns, local and average Nusselt number variation along the hot wall for different parametric conditions. It is found that, presence of heat conducting rotating cylinder increases the heat transfer significantly particularly in the lower range of Reynolds numbers considered in the present study and enhancement of heat transfer occurs as the Prandtl number increases. Thus, dynamic condition of the rotating cylinder and the thermophysical properties of working fluid play dominant roles for enhancing the heat transfer characteristics and flow behavior within the long horizontal channel.Two-dimensional, laminar, steady mixed convection heat transfer in a long horizontal channel has been investigated numerically with flow modulation through periodically distributed heat conducting rotating cylinders. The upper wall of the channel is maintained at constant low temperature and the lower wall is maintained at constant high temperature. A series of heat conducting rotating cylinders is placed periodically along the centerline of the channel with a spacing between two successive cylinders being equal to the height of the channel. The mathematical model of the present problem is governed by two-dimensional continuity, momentum and energy equations. The governing equations are then transformed to non-dimensional forms that are solved by using Galerkin finite element method with triangular discretization system. Water, air and liquid Gallium are considered as the working fluids. Numerical simulation is performed for case of pure mixed convection heat transfer characterized by a Richardson number ...
{"title":"Enhancement of conjugate mixed convection heat transfer in a long horizontal channel with multiple rotating cylinders","authors":"M. Islam, Shajedul Hoque Thakur, Abrar Ul Karim, S. Saha, M. Hasan","doi":"10.1063/1.5115923","DOIUrl":"https://doi.org/10.1063/1.5115923","url":null,"abstract":"Two-dimensional, laminar, steady mixed convection heat transfer in a long horizontal channel has been investigated numerically with flow modulation through periodically distributed heat conducting rotating cylinders. The upper wall of the channel is maintained at constant low temperature and the lower wall is maintained at constant high temperature. A series of heat conducting rotating cylinders is placed periodically along the centerline of the channel with a spacing between two successive cylinders being equal to the height of the channel. The mathematical model of the present problem is governed by two-dimensional continuity, momentum and energy equations. The governing equations are then transformed to non-dimensional forms that are solved by using Galerkin finite element method with triangular discretization system. Water, air and liquid Gallium are considered as the working fluids. Numerical simulation is performed for case of pure mixed convection heat transfer characterized by a Richardson number of unity. Parametric simulation is carried out for a wide range of Reynolds numbers (1 ≤ Re ≤500) based on the dynamic condition of the rotating cylinder. Numerical results are presented and analyzed in terms of the distribution of streamline and isotherm patterns, local and average Nusselt number variation along the hot wall for different parametric conditions. It is found that, presence of heat conducting rotating cylinder increases the heat transfer significantly particularly in the lower range of Reynolds numbers considered in the present study and enhancement of heat transfer occurs as the Prandtl number increases. Thus, dynamic condition of the rotating cylinder and the thermophysical properties of working fluid play dominant roles for enhancing the heat transfer characteristics and flow behavior within the long horizontal channel.Two-dimensional, laminar, steady mixed convection heat transfer in a long horizontal channel has been investigated numerically with flow modulation through periodically distributed heat conducting rotating cylinders. The upper wall of the channel is maintained at constant low temperature and the lower wall is maintained at constant high temperature. A series of heat conducting rotating cylinders is placed periodically along the centerline of the channel with a spacing between two successive cylinders being equal to the height of the channel. The mathematical model of the present problem is governed by two-dimensional continuity, momentum and energy equations. The governing equations are then transformed to non-dimensional forms that are solved by using Galerkin finite element method with triangular discretization system. Water, air and liquid Gallium are considered as the working fluids. Numerical simulation is performed for case of pure mixed convection heat transfer characterized by a Richardson number ...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122137591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Plastic is made from wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. The yearly use of plastics in Bangladesh has grown to 12,00,000 metric tons in 2018. A part of it is recycled but Bangladesh still generates 8,00,000 tons of plastic wastes every year. Disposal of plastic is of great environmental concern now-a-days, as it seizes centuries to decompose if left at its own. Conversion of waste plastic to fuel oil mitigates both plastic pollution problem and fuel crisis. This study focuses on the thermal degradation of polypropylene plastic wastes by pyrolysis process without any catalyst to produce fuel oil. A small scale batch type set up was built to perform thermal degradation of plastic. Polypropylene plastic wastes were cleaned, shredded and pyrolysed from 300-400°C for 60 minutes in this setup. The yield products were liquid fuel oil, gas and black solid plastic residue. These pyrolysed products were collected and characterized by different experimental and analytical methods. The conversion efficiency of oil achieved by the set up was 78% by mass. 73% plastic waste volume reduction was obtained by converting it into fuel oil from solid waste. Equivalent energy output calculated from measured heating value of pyrolytic oil which was obtained from 60 minutes pyrolysis was 12.8MJ/kg. Properties of the fuel oil produced such as - calorific value, viscosity, density, flash point and water content were measured and all of these properties were found to be very close to that of diesel and octane. The products obtained have potential values for further use as fuel oil, lubricating oil, diesel supplement etc which may provide solution as alternative energy resource.Plastic is made from wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. The yearly use of plastics in Bangladesh has grown to 12,00,000 metric tons in 2018. A part of it is recycled but Bangladesh still generates 8,00,000 tons of plastic wastes every year. Disposal of plastic is of great environmental concern now-a-days, as it seizes centuries to decompose if left at its own. Conversion of waste plastic to fuel oil mitigates both plastic pollution problem and fuel crisis. This study focuses on the thermal degradation of polypropylene plastic wastes by pyrolysis process without any catalyst to produce fuel oil. A small scale batch type set up was built to perform thermal degradation of plastic. Polypropylene plastic wastes were cleaned, shredded and pyrolysed from 300-400°C for 60 minutes in this setup. The yield products were liquid fuel oil, gas and black solid plastic residue. These pyrolysed products were collected and characterized b...
{"title":"Conversion of waste polypropylene plastic into fuel","authors":"Mahbuba Jannat, S. Akter, M. Ehsan","doi":"10.1063/1.5115946","DOIUrl":"https://doi.org/10.1063/1.5115946","url":null,"abstract":"Plastic is made from wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. The yearly use of plastics in Bangladesh has grown to 12,00,000 metric tons in 2018. A part of it is recycled but Bangladesh still generates 8,00,000 tons of plastic wastes every year. Disposal of plastic is of great environmental concern now-a-days, as it seizes centuries to decompose if left at its own. Conversion of waste plastic to fuel oil mitigates both plastic pollution problem and fuel crisis. This study focuses on the thermal degradation of polypropylene plastic wastes by pyrolysis process without any catalyst to produce fuel oil. A small scale batch type set up was built to perform thermal degradation of plastic. Polypropylene plastic wastes were cleaned, shredded and pyrolysed from 300-400°C for 60 minutes in this setup. The yield products were liquid fuel oil, gas and black solid plastic residue. These pyrolysed products were collected and characterized by different experimental and analytical methods. The conversion efficiency of oil achieved by the set up was 78% by mass. 73% plastic waste volume reduction was obtained by converting it into fuel oil from solid waste. Equivalent energy output calculated from measured heating value of pyrolytic oil which was obtained from 60 minutes pyrolysis was 12.8MJ/kg. Properties of the fuel oil produced such as - calorific value, viscosity, density, flash point and water content were measured and all of these properties were found to be very close to that of diesel and octane. The products obtained have potential values for further use as fuel oil, lubricating oil, diesel supplement etc which may provide solution as alternative energy resource.Plastic is made from wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. The yearly use of plastics in Bangladesh has grown to 12,00,000 metric tons in 2018. A part of it is recycled but Bangladesh still generates 8,00,000 tons of plastic wastes every year. Disposal of plastic is of great environmental concern now-a-days, as it seizes centuries to decompose if left at its own. Conversion of waste plastic to fuel oil mitigates both plastic pollution problem and fuel crisis. This study focuses on the thermal degradation of polypropylene plastic wastes by pyrolysis process without any catalyst to produce fuel oil. A small scale batch type set up was built to perform thermal degradation of plastic. Polypropylene plastic wastes were cleaned, shredded and pyrolysed from 300-400°C for 60 minutes in this setup. The yield products were liquid fuel oil, gas and black solid plastic residue. These pyrolysed products were collected and characterized b...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128037341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A precise understanding of the aerosol particle transport and deposition (TD) in the realistic mouth-throat model is important for the respiratory health risk assessment and effective delivery of the aerosol medicine to the targeted positions of the lung. A wide range of studies have developed the particle TD framework for both idealized and non-idealized extra-thoracic airways. However, all of the existing in silico and experimental model reports a significant amount of aerosol particles are deposit at the extra-thoracic airways and the existing drug delivery device can deliver only 12 percent of the aerosol drug to the targeted position of the lung. This study aims to increase the efficiency of the targeted drug delivery by developing a realistic particle transport model for CT-Scan based mouth-throat replica. A 3-D realistic mouth-throat model is developed from the CT-Scan DiCom images of a healthy adult cast. High-Quality computational cells are generated for the replica model and the proper grid refinement test has been performed. ANSYS Fluent (19.1) solver is used for the particle TD computation. Tecplot and MATLAB software are used for the post-processing purpose. The numerical results report that the breathing pattern and particle diameter influences the overall particle TD in the mouth-throat model. The numerical results also depict different deposition hot spots for the mouth-throat model, which will eventually help to design a better drug delivery device. The numerical results reported that only 13.67 percent of the 10-μm diameter particles are deposited at the mouth-throat model at 15 lpm flow rate and which indicate that the remaining particles will move to the beyond airways. The present results along with more case studies will develop the understanding of the realistic particle deposition in the extrathoracic airways.A precise understanding of the aerosol particle transport and deposition (TD) in the realistic mouth-throat model is important for the respiratory health risk assessment and effective delivery of the aerosol medicine to the targeted positions of the lung. A wide range of studies have developed the particle TD framework for both idealized and non-idealized extra-thoracic airways. However, all of the existing in silico and experimental model reports a significant amount of aerosol particles are deposit at the extra-thoracic airways and the existing drug delivery device can deliver only 12 percent of the aerosol drug to the targeted position of the lung. This study aims to increase the efficiency of the targeted drug delivery by developing a realistic particle transport model for CT-Scan based mouth-throat replica. A 3-D realistic mouth-throat model is developed from the CT-Scan DiCom images of a healthy adult cast. High-Quality computational cells are generated for the replica model and the proper grid refi...
{"title":"Aerosol particle transport and deposition in a CT-scan based mouth-throat model","authors":"S. Saha, M. Islam, M. Rahimi-Gorji, M. Molla","doi":"10.1063/1.5115882","DOIUrl":"https://doi.org/10.1063/1.5115882","url":null,"abstract":"A precise understanding of the aerosol particle transport and deposition (TD) in the realistic mouth-throat model is important for the respiratory health risk assessment and effective delivery of the aerosol medicine to the targeted positions of the lung. A wide range of studies have developed the particle TD framework for both idealized and non-idealized extra-thoracic airways. However, all of the existing in silico and experimental model reports a significant amount of aerosol particles are deposit at the extra-thoracic airways and the existing drug delivery device can deliver only 12 percent of the aerosol drug to the targeted position of the lung. This study aims to increase the efficiency of the targeted drug delivery by developing a realistic particle transport model for CT-Scan based mouth-throat replica. A 3-D realistic mouth-throat model is developed from the CT-Scan DiCom images of a healthy adult cast. High-Quality computational cells are generated for the replica model and the proper grid refinement test has been performed. ANSYS Fluent (19.1) solver is used for the particle TD computation. Tecplot and MATLAB software are used for the post-processing purpose. The numerical results report that the breathing pattern and particle diameter influences the overall particle TD in the mouth-throat model. The numerical results also depict different deposition hot spots for the mouth-throat model, which will eventually help to design a better drug delivery device. The numerical results reported that only 13.67 percent of the 10-μm diameter particles are deposited at the mouth-throat model at 15 lpm flow rate and which indicate that the remaining particles will move to the beyond airways. The present results along with more case studies will develop the understanding of the realistic particle deposition in the extrathoracic airways.A precise understanding of the aerosol particle transport and deposition (TD) in the realistic mouth-throat model is important for the respiratory health risk assessment and effective delivery of the aerosol medicine to the targeted positions of the lung. A wide range of studies have developed the particle TD framework for both idealized and non-idealized extra-thoracic airways. However, all of the existing in silico and experimental model reports a significant amount of aerosol particles are deposit at the extra-thoracic airways and the existing drug delivery device can deliver only 12 percent of the aerosol drug to the targeted position of the lung. This study aims to increase the efficiency of the targeted drug delivery by developing a realistic particle transport model for CT-Scan based mouth-throat replica. A 3-D realistic mouth-throat model is developed from the CT-Scan DiCom images of a healthy adult cast. High-Quality computational cells are generated for the replica model and the proper grid refi...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124603478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study reports the science-based fire scene reconstruction of a fatal fire that occurred in a high-rise residential building in Dhaka in 2010, taking the lives of 7 inhabitants. Numerical methods have been applied to analyze the deadly event in order to demonstrate different smoke propagation and to compare them with the official investigation report on the actual incident. In this investigation, Computational Fluid Dynamics (CFD)-based fire dynamics simulator PyroSim is used for exploring the fire spread and smoke propagation. The results suggest that teak wood would not have been the only fuel source in this incident. It is proposed that burning of other fuel with higher CO yield such as turpentine oil or white spirit, in addition to the teak wood in the apartment where interior decoration and carpentry work was going on and where the fire was initiated, results in the required high level of CO to cause the asphyxiation of the trapped occupants. It is also to be mentioned that the victims of casualty were entrapped by the smoke within the main staircase due to a drop in the tenability which caused the fatality. By analyzing the effects of smoke temperature, visibility, CO concentration, the tenability limit for this residential building is measured. The use of engineering analysis and modelling of fire for fire forensic analysis is considered to be an important tool in fire investigation, this paper reports first such study in Bangladesh.The present study reports the science-based fire scene reconstruction of a fatal fire that occurred in a high-rise residential building in Dhaka in 2010, taking the lives of 7 inhabitants. Numerical methods have been applied to analyze the deadly event in order to demonstrate different smoke propagation and to compare them with the official investigation report on the actual incident. In this investigation, Computational Fluid Dynamics (CFD)-based fire dynamics simulator PyroSim is used for exploring the fire spread and smoke propagation. The results suggest that teak wood would not have been the only fuel source in this incident. It is proposed that burning of other fuel with higher CO yield such as turpentine oil or white spirit, in addition to the teak wood in the apartment where interior decoration and carpentry work was going on and where the fire was initiated, results in the required high level of CO to cause the asphyxiation of the trapped occupants. It is also to be mentioned that the victims of ...
{"title":"Forensic analysis of a fatal fire incident in a high-rise residential building in Bangladesh, 2010 using fire modelling","authors":"S. Mahmud, F. Haque, M. Rahman","doi":"10.1063/1.5115930","DOIUrl":"https://doi.org/10.1063/1.5115930","url":null,"abstract":"The present study reports the science-based fire scene reconstruction of a fatal fire that occurred in a high-rise residential building in Dhaka in 2010, taking the lives of 7 inhabitants. Numerical methods have been applied to analyze the deadly event in order to demonstrate different smoke propagation and to compare them with the official investigation report on the actual incident. In this investigation, Computational Fluid Dynamics (CFD)-based fire dynamics simulator PyroSim is used for exploring the fire spread and smoke propagation. The results suggest that teak wood would not have been the only fuel source in this incident. It is proposed that burning of other fuel with higher CO yield such as turpentine oil or white spirit, in addition to the teak wood in the apartment where interior decoration and carpentry work was going on and where the fire was initiated, results in the required high level of CO to cause the asphyxiation of the trapped occupants. It is also to be mentioned that the victims of casualty were entrapped by the smoke within the main staircase due to a drop in the tenability which caused the fatality. By analyzing the effects of smoke temperature, visibility, CO concentration, the tenability limit for this residential building is measured. The use of engineering analysis and modelling of fire for fire forensic analysis is considered to be an important tool in fire investigation, this paper reports first such study in Bangladesh.The present study reports the science-based fire scene reconstruction of a fatal fire that occurred in a high-rise residential building in Dhaka in 2010, taking the lives of 7 inhabitants. Numerical methods have been applied to analyze the deadly event in order to demonstrate different smoke propagation and to compare them with the official investigation report on the actual incident. In this investigation, Computational Fluid Dynamics (CFD)-based fire dynamics simulator PyroSim is used for exploring the fire spread and smoke propagation. The results suggest that teak wood would not have been the only fuel source in this incident. It is proposed that burning of other fuel with higher CO yield such as turpentine oil or white spirit, in addition to the teak wood in the apartment where interior decoration and carpentry work was going on and where the fire was initiated, results in the required high level of CO to cause the asphyxiation of the trapped occupants. It is also to be mentioned that the victims of ...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123822216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present study a single expansion ramp nozzle (SERN) system is studied with nozzle pressure ratio (NPR) of 2.9. An interaction of subsonic ambient inflow with M∞ of 0.4 which is induced during take-off of a typical hypersonic vehicle with SERN is considered. Different ambient angles of attack of 0°, −5°, −10° and −15° have been studied. Results obtained by numerical computation are validated by available experimental data. A significant amount of separation is developed at the walls (on both ramp and flap) due to shock wave-boundary layer interaction (SWBLI). Due to the ambient inflow at different angles of attack the separation patterns changes from restricted shock separation (RSS) to free shock separation (FSS). This transition happens when angle of attack changes from 0° to −5° at ambient inflow Mach number of 0.4. Due to ambient stream interaction shock wave oscillates and wall pressure distribution on both ramp and flap changes with time for different ambient inflow conditions. This flow field instability is expressed by the distribution of root means square (RMS) value of pressure over ramp and flap. The main purpose of SERN is generation of thrust of hypersonic vehicles. So thrust and thrust vector angle are important parameters of SERN. Thrust and thrust vector angle of SERN is related to separation pattern. This study gives an insight to the flow structure in SERN when there is a strong ambient inflow and can be very beneficial to the design and performance analysis of SERN.In the present study a single expansion ramp nozzle (SERN) system is studied with nozzle pressure ratio (NPR) of 2.9. An interaction of subsonic ambient inflow with M∞ of 0.4 which is induced during take-off of a typical hypersonic vehicle with SERN is considered. Different ambient angles of attack of 0°, −5°, −10° and −15° have been studied. Results obtained by numerical computation are validated by available experimental data. A significant amount of separation is developed at the walls (on both ramp and flap) due to shock wave-boundary layer interaction (SWBLI). Due to the ambient inflow at different angles of attack the separation patterns changes from restricted shock separation (RSS) to free shock separation (FSS). This transition happens when angle of attack changes from 0° to −5° at ambient inflow Mach number of 0.4. Due to ambient stream interaction shock wave oscillates and wall pressure distribution on both ramp and flap changes with time for different ambient inflow conditions. This flow field...
{"title":"Subsonic ambient stream interaction on flow characteristics around a single expansion ramp nozzle","authors":"S. Barua, Sourov Mondal, A. Hasan","doi":"10.1063/1.5115901","DOIUrl":"https://doi.org/10.1063/1.5115901","url":null,"abstract":"In the present study a single expansion ramp nozzle (SERN) system is studied with nozzle pressure ratio (NPR) of 2.9. An interaction of subsonic ambient inflow with M∞ of 0.4 which is induced during take-off of a typical hypersonic vehicle with SERN is considered. Different ambient angles of attack of 0°, −5°, −10° and −15° have been studied. Results obtained by numerical computation are validated by available experimental data. A significant amount of separation is developed at the walls (on both ramp and flap) due to shock wave-boundary layer interaction (SWBLI). Due to the ambient inflow at different angles of attack the separation patterns changes from restricted shock separation (RSS) to free shock separation (FSS). This transition happens when angle of attack changes from 0° to −5° at ambient inflow Mach number of 0.4. Due to ambient stream interaction shock wave oscillates and wall pressure distribution on both ramp and flap changes with time for different ambient inflow conditions. This flow field instability is expressed by the distribution of root means square (RMS) value of pressure over ramp and flap. The main purpose of SERN is generation of thrust of hypersonic vehicles. So thrust and thrust vector angle are important parameters of SERN. Thrust and thrust vector angle of SERN is related to separation pattern. This study gives an insight to the flow structure in SERN when there is a strong ambient inflow and can be very beneficial to the design and performance analysis of SERN.In the present study a single expansion ramp nozzle (SERN) system is studied with nozzle pressure ratio (NPR) of 2.9. An interaction of subsonic ambient inflow with M∞ of 0.4 which is induced during take-off of a typical hypersonic vehicle with SERN is considered. Different ambient angles of attack of 0°, −5°, −10° and −15° have been studied. Results obtained by numerical computation are validated by available experimental data. A significant amount of separation is developed at the walls (on both ramp and flap) due to shock wave-boundary layer interaction (SWBLI). Due to the ambient inflow at different angles of attack the separation patterns changes from restricted shock separation (RSS) to free shock separation (FSS). This transition happens when angle of attack changes from 0° to −5° at ambient inflow Mach number of 0.4. Due to ambient stream interaction shock wave oscillates and wall pressure distribution on both ramp and flap changes with time for different ambient inflow conditions. This flow field...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124261665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this research, a non-Newtonian model for blood flow within a stenosed artery is investigated numerically. Finite Element Method of Galerkin’s weighted residual scheme is used to solve the transport equations with appropriate boundary conditions. The main objective of this study is to explore the influence of magnetic field on the blood flow. The numerical results are presented in terms of the velocity, pressure distribution and shear rate of the stenosed artery.In this research, a non-Newtonian model for blood flow within a stenosed artery is investigated numerically. Finite Element Method of Galerkin’s weighted residual scheme is used to solve the transport equations with appropriate boundary conditions. The main objective of this study is to explore the influence of magnetic field on the blood flow. The numerical results are presented in terms of the velocity, pressure distribution and shear rate of the stenosed artery.
{"title":"Numerical analysis of a blood flow model for arterial stenosis in presence of external magnetic field","authors":"A. Akter, S. Parvin","doi":"10.1063/1.5115932","DOIUrl":"https://doi.org/10.1063/1.5115932","url":null,"abstract":"In this research, a non-Newtonian model for blood flow within a stenosed artery is investigated numerically. Finite Element Method of Galerkin’s weighted residual scheme is used to solve the transport equations with appropriate boundary conditions. The main objective of this study is to explore the influence of magnetic field on the blood flow. The numerical results are presented in terms of the velocity, pressure distribution and shear rate of the stenosed artery.In this research, a non-Newtonian model for blood flow within a stenosed artery is investigated numerically. Finite Element Method of Galerkin’s weighted residual scheme is used to solve the transport equations with appropriate boundary conditions. The main objective of this study is to explore the influence of magnetic field on the blood flow. The numerical results are presented in terms of the velocity, pressure distribution and shear rate of the stenosed artery.","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122583067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dry-sliding wear and frictional behavior of a polymeric matrix material commonly used in fiber-reinforced composite applications are investigated as a function of thermal ageing temperature. More specifically, the commercially available polyester resin is used in this study to prepare disc-like samples of diameter 75mm and thickness 3mm, which are then aged isochronally at temperatures of 25°C, 75°C, 100°C and 125°C for a period of one hour. The wear test has been carried out against a high-speed carbon steel pin with a diameter of 5mm at a test load of 10N, in which the sliding distance is varied from 20m to 1450m with a sliding velocity of 0.4ms−1. The wear and frictional behavior of the polyester resin are found to be improved quite significantly when the samples are thermally treated at a temperature of around 125°C. At lower temperatures, softening of the polymeric sheet occurs due to minimum heat generation, which, in turn, results in a reduction of hardness and wear resistance. A surface investigation by scanning electron microscopic (SEM) images reveals that some casting defects are present in the form of pores in the original non-worn surfaces, whereas the worn surfaces are subjected to a resultant of severe plastic deformation and scuffing when the polyester resin samples are thermally treated at 125°C.The dry-sliding wear and frictional behavior of a polymeric matrix material commonly used in fiber-reinforced composite applications are investigated as a function of thermal ageing temperature. More specifically, the commercially available polyester resin is used in this study to prepare disc-like samples of diameter 75mm and thickness 3mm, which are then aged isochronally at temperatures of 25°C, 75°C, 100°C and 125°C for a period of one hour. The wear test has been carried out against a high-speed carbon steel pin with a diameter of 5mm at a test load of 10N, in which the sliding distance is varied from 20m to 1450m with a sliding velocity of 0.4ms−1. The wear and frictional behavior of the polyester resin are found to be improved quite significantly when the samples are thermally treated at a temperature of around 125°C. At lower temperatures, softening of the polymeric sheet occurs due to minimum heat generation, which, in turn, results in a reduction of hardness and wear resistance. A surface invest...
{"title":"Effect of thermal ageing on dry-sliding wear behavior of polymeric matrix materials used in FRC applications","authors":"F. Tabassum, R. Asekin, M. S. Kaiser, S. R. Ahmed","doi":"10.1063/1.5115961","DOIUrl":"https://doi.org/10.1063/1.5115961","url":null,"abstract":"The dry-sliding wear and frictional behavior of a polymeric matrix material commonly used in fiber-reinforced composite applications are investigated as a function of thermal ageing temperature. More specifically, the commercially available polyester resin is used in this study to prepare disc-like samples of diameter 75mm and thickness 3mm, which are then aged isochronally at temperatures of 25°C, 75°C, 100°C and 125°C for a period of one hour. The wear test has been carried out against a high-speed carbon steel pin with a diameter of 5mm at a test load of 10N, in which the sliding distance is varied from 20m to 1450m with a sliding velocity of 0.4ms−1. The wear and frictional behavior of the polyester resin are found to be improved quite significantly when the samples are thermally treated at a temperature of around 125°C. At lower temperatures, softening of the polymeric sheet occurs due to minimum heat generation, which, in turn, results in a reduction of hardness and wear resistance. A surface investigation by scanning electron microscopic (SEM) images reveals that some casting defects are present in the form of pores in the original non-worn surfaces, whereas the worn surfaces are subjected to a resultant of severe plastic deformation and scuffing when the polyester resin samples are thermally treated at 125°C.The dry-sliding wear and frictional behavior of a polymeric matrix material commonly used in fiber-reinforced composite applications are investigated as a function of thermal ageing temperature. More specifically, the commercially available polyester resin is used in this study to prepare disc-like samples of diameter 75mm and thickness 3mm, which are then aged isochronally at temperatures of 25°C, 75°C, 100°C and 125°C for a period of one hour. The wear test has been carried out against a high-speed carbon steel pin with a diameter of 5mm at a test load of 10N, in which the sliding distance is varied from 20m to 1450m with a sliding velocity of 0.4ms−1. The wear and frictional behavior of the polyester resin are found to be improved quite significantly when the samples are thermally treated at a temperature of around 125°C. At lower temperatures, softening of the polymeric sheet occurs due to minimum heat generation, which, in turn, results in a reduction of hardness and wear resistance. A surface invest...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"292 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115133084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shajedul Hoque Thakur, M. Islam, Abrar Ul Karim, S. Saha, M. Hasan
A numerical study of two-dimensional, laminar, steady mixed convection heat transfer in a Cu-water nanofluid filled lid-driven square cavity with an isothermally heated cylinder has been conducted. The wall of the cylinder is maintained at a constant high temperature, whereas the walls of the cavity (including the moving lid) are maintained at a constant low temperature. The isothermally heated cylinder is placed at the center of the cavity. The fluid flow in the cavity is driven by the combined effect of the buoyancy force due to temperature gradient and forced flow due to the top moving wall in the +x direction. The developed mathematical model is governed by the two-dimensional continuity, momentum and energy equations, which are solved by using Galerkin finite element method. The working fluid inside the cavity is Cu-water nanofluid, where water has been considered as the base fluid. The influence of the Reynolds number (1 ≤ Re ≤ 500) and the solid volume fraction of the Cu nanoparticle (0≤ ϕ ≤0.05) on fluid flow and heat transfer has been numerically investigated for the case of pure mixed convection heat transfer. Numerical results are presented in terms of the distribution of streamlines and isothermal contours, local as well as average Nusselt number variation on the cylinder surface for different parametric conditions. It is observed that enhancement of heat transfer occurs significantly as Reynolds number and solid volume fraction of nanoparticle change continuously. Thus, the dynamic condition of the moving lid and solid volume fraction of the nanoparticle can be used as parameters for enhancing the heat transfer characteristics and flow behavior in that cavity.
{"title":"Numerical study of laminar mixed convection in a Cu-water nanofluid filled lid-driven square cavity with an isothermally heated cylinder","authors":"Shajedul Hoque Thakur, M. Islam, Abrar Ul Karim, S. Saha, M. Hasan","doi":"10.1063/1.5115924","DOIUrl":"https://doi.org/10.1063/1.5115924","url":null,"abstract":"A numerical study of two-dimensional, laminar, steady mixed convection heat transfer in a Cu-water nanofluid filled lid-driven square cavity with an isothermally heated cylinder has been conducted. The wall of the cylinder is maintained at a constant high temperature, whereas the walls of the cavity (including the moving lid) are maintained at a constant low temperature. The isothermally heated cylinder is placed at the center of the cavity. The fluid flow in the cavity is driven by the combined effect of the buoyancy force due to temperature gradient and forced flow due to the top moving wall in the +x direction. The developed mathematical model is governed by the two-dimensional continuity, momentum and energy equations, which are solved by using Galerkin finite element method. The working fluid inside the cavity is Cu-water nanofluid, where water has been considered as the base fluid. The influence of the Reynolds number (1 ≤ Re ≤ 500) and the solid volume fraction of the Cu nanoparticle (0≤ ϕ ≤0.05) on fluid flow and heat transfer has been numerically investigated for the case of pure mixed convection heat transfer. Numerical results are presented in terms of the distribution of streamlines and isothermal contours, local as well as average Nusselt number variation on the cylinder surface for different parametric conditions. It is observed that enhancement of heat transfer occurs significantly as Reynolds number and solid volume fraction of nanoparticle change continuously. Thus, the dynamic condition of the moving lid and solid volume fraction of the nanoparticle can be used as parameters for enhancing the heat transfer characteristics and flow behavior in that cavity.","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127978859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The unsteady MHD free convection Maxwell nanofluid flow through an exponentially accelerated vertical surface with the presence of radiation and chemical reaction is investigated in this present study. For obtaining numerical solutions, the governing partial differential equations (PDEs) are transformed into dimensionless partial differential equations (PDEs) with the as usual mathematical transformation. Explicit finite difference method (EFDM) is used for numerical solutions where ForTran programing language have been used as the main tool of investigations. The stability analysis technique (SAT) is used for choosing the appropriate values of parameters. Then, the obtained numerical results are affected by this various dimensionless parameters such as magnetic parameter (M), Maxwell parameter (Mx), Schmidt number (Sc), Grashof number (Gr), Lewis number (Le) and so on. The velocity, temperature and concentration profiles along with the skin friction coefficient (Cf), Nusselt number (Nu) and Sherwood number (Sh) are analysed for different perspective. Furthermore, the streamlines and isotherms are discussed for different interesting parameters in this work. Finally, the results are discussed after stability convergence test (SCT) by using graphics software tecplot-9 and comparison of our results with the previous results have been presented in a tabular form.The unsteady MHD free convection Maxwell nanofluid flow through an exponentially accelerated vertical surface with the presence of radiation and chemical reaction is investigated in this present study. For obtaining numerical solutions, the governing partial differential equations (PDEs) are transformed into dimensionless partial differential equations (PDEs) with the as usual mathematical transformation. Explicit finite difference method (EFDM) is used for numerical solutions where ForTran programing language have been used as the main tool of investigations. The stability analysis technique (SAT) is used for choosing the appropriate values of parameters. Then, the obtained numerical results are affected by this various dimensionless parameters such as magnetic parameter (M), Maxwell parameter (Mx), Schmidt number (Sc), Grashof number (Gr), Lewis number (Le) and so on. The velocity, temperature and concentration profiles along with the skin friction coefficient (Cf), Nusselt number (Nu) and Sherwood numb...
{"title":"MHD free convection Maxwell nanofluid flow through an exponentially accelerated vertical surface in the presence of radiation","authors":"R. Biswas, M. Hasan, B. Rana, S. Ahmmed","doi":"10.1063/1.5115852","DOIUrl":"https://doi.org/10.1063/1.5115852","url":null,"abstract":"The unsteady MHD free convection Maxwell nanofluid flow through an exponentially accelerated vertical surface with the presence of radiation and chemical reaction is investigated in this present study. For obtaining numerical solutions, the governing partial differential equations (PDEs) are transformed into dimensionless partial differential equations (PDEs) with the as usual mathematical transformation. Explicit finite difference method (EFDM) is used for numerical solutions where ForTran programing language have been used as the main tool of investigations. The stability analysis technique (SAT) is used for choosing the appropriate values of parameters. Then, the obtained numerical results are affected by this various dimensionless parameters such as magnetic parameter (M), Maxwell parameter (Mx), Schmidt number (Sc), Grashof number (Gr), Lewis number (Le) and so on. The velocity, temperature and concentration profiles along with the skin friction coefficient (Cf), Nusselt number (Nu) and Sherwood number (Sh) are analysed for different perspective. Furthermore, the streamlines and isotherms are discussed for different interesting parameters in this work. Finally, the results are discussed after stability convergence test (SCT) by using graphics software tecplot-9 and comparison of our results with the previous results have been presented in a tabular form.The unsteady MHD free convection Maxwell nanofluid flow through an exponentially accelerated vertical surface with the presence of radiation and chemical reaction is investigated in this present study. For obtaining numerical solutions, the governing partial differential equations (PDEs) are transformed into dimensionless partial differential equations (PDEs) with the as usual mathematical transformation. Explicit finite difference method (EFDM) is used for numerical solutions where ForTran programing language have been used as the main tool of investigations. The stability analysis technique (SAT) is used for choosing the appropriate values of parameters. Then, the obtained numerical results are affected by this various dimensionless parameters such as magnetic parameter (M), Maxwell parameter (Mx), Schmidt number (Sc), Grashof number (Gr), Lewis number (Le) and so on. The velocity, temperature and concentration profiles along with the skin friction coefficient (Cf), Nusselt number (Nu) and Sherwood numb...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"321 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127568303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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