S. Saha, S. Subedi, Indrajit Nandi, M. Hasan, S. Saha
In the present study, a numerical approach using finite element method has been carried out to investigate fully developed turbulent flow and heat transfer in a smooth two-dimensional axi-symmetric pipe. Four different turbulence models, namely Shear Stress Transport (SST), Spalart-Allmaras, Length VELocity (L-VEL) and Algebraic yPlus are selected along with Reynolds Averaged Navier-Stokes (RANS) and thermal energy equations for numerical simulation. Parametric simulation has been carried out at a fixed Karman number, Reτ = 180 with different Prandtl numbers Pr = 0.71, 2 and 5. The numerical results obtained from different turbulence models are then compared with the available direct numerical simulation (DNS) data in terms of both inner and outer scaling. From the comparative study, it is found that SST model has good agreement with DNS results and can be used to predict turbulent pipe flow and heat transfer for higher Reynolds and Prandtl numbers.
{"title":"Assessment of turbulence models for heat transfer in axi-symmetric pipe flow","authors":"S. Saha, S. Subedi, Indrajit Nandi, M. Hasan, S. Saha","doi":"10.1063/1.5115865","DOIUrl":"https://doi.org/10.1063/1.5115865","url":null,"abstract":"In the present study, a numerical approach using finite element method has been carried out to investigate fully developed turbulent flow and heat transfer in a smooth two-dimensional axi-symmetric pipe. Four different turbulence models, namely Shear Stress Transport (SST), Spalart-Allmaras, Length VELocity (L-VEL) and Algebraic yPlus are selected along with Reynolds Averaged Navier-Stokes (RANS) and thermal energy equations for numerical simulation. Parametric simulation has been carried out at a fixed Karman number, Reτ = 180 with different Prandtl numbers Pr = 0.71, 2 and 5. The numerical results obtained from different turbulence models are then compared with the available direct numerical simulation (DNS) data in terms of both inner and outer scaling. From the comparative study, it is found that SST model has good agreement with DNS results and can be used to predict turbulent pipe flow and heat transfer for higher Reynolds and Prandtl numbers.","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"17 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":"122315038","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 finite element Fluid-Structure-Interaction (FSI) model is developed and validated for hemodynamic pulsatile blood flow through a stenosed artery under the effect of an applied magnetic field. The two-layered blood flow is considered with a core layer of suspension of all erythrocytes assumed to be a non-Newtonian Casson fluid and a peripheral layer of plasma, free from cells, as a Newtonian fluid. The model is considered for the 2D idealized elastic arteries. The blood flow is characterized as a steady, laminar, incompressible and unidirectional flow velocity at the inflow and various values of blood-pressure at the outflow, while the arterial walls as well as the surrounding muscles are modeled as a hyperelastic neo-Hookean material and results are obtained for axial velocities, total flow rate, pressure gradient and wall shear stresses (WSS) and solid displacement due to blood pulse. The result shows significant strengthened WSS at the stenotic regions and weakened WSS at the distal side of stenosis neck. It is found that the increase of stenosis size (height) increases the pressure drop and WSS, whereas velocity and flow rate decreases. The wall deformation and WSS may play an important role in the flow mechanics of blood in the stenotic vessel. It is also observed that the fluid velocity and flow rate were reduced when the magnetic field was introduced as well as when its intensity was increased, while WSS was increased with the increase of Hartmann number (Ha) as well as Reynolds number (Re). This work may enhance to work upon the strength of magnetic field to regulate the blood flow in hypertensive patients and those who have blockage in their arteries.A finite element Fluid-Structure-Interaction (FSI) model is developed and validated for hemodynamic pulsatile blood flow through a stenosed artery under the effect of an applied magnetic field. The two-layered blood flow is considered with a core layer of suspension of all erythrocytes assumed to be a non-Newtonian Casson fluid and a peripheral layer of plasma, free from cells, as a Newtonian fluid. The model is considered for the 2D idealized elastic arteries. The blood flow is characterized as a steady, laminar, incompressible and unidirectional flow velocity at the inflow and various values of blood-pressure at the outflow, while the arterial walls as well as the surrounding muscles are modeled as a hyperelastic neo-Hookean material and results are obtained for axial velocities, total flow rate, pressure gradient and wall shear stresses (WSS) and solid displacement due to blood pulse. The result shows significant strengthened WSS at the stenotic regions and weakened WSS at the distal side of stenosis n...
{"title":"Hemodynamic blood flow through a section of human artery under the effect of applied magnetic field","authors":"A. Karim, M. Hossain, S. Parvin, M. A. H. Khan","doi":"10.1063/1.5115897","DOIUrl":"https://doi.org/10.1063/1.5115897","url":null,"abstract":"A finite element Fluid-Structure-Interaction (FSI) model is developed and validated for hemodynamic pulsatile blood flow through a stenosed artery under the effect of an applied magnetic field. The two-layered blood flow is considered with a core layer of suspension of all erythrocytes assumed to be a non-Newtonian Casson fluid and a peripheral layer of plasma, free from cells, as a Newtonian fluid. The model is considered for the 2D idealized elastic arteries. The blood flow is characterized as a steady, laminar, incompressible and unidirectional flow velocity at the inflow and various values of blood-pressure at the outflow, while the arterial walls as well as the surrounding muscles are modeled as a hyperelastic neo-Hookean material and results are obtained for axial velocities, total flow rate, pressure gradient and wall shear stresses (WSS) and solid displacement due to blood pulse. The result shows significant strengthened WSS at the stenotic regions and weakened WSS at the distal side of stenosis neck. It is found that the increase of stenosis size (height) increases the pressure drop and WSS, whereas velocity and flow rate decreases. The wall deformation and WSS may play an important role in the flow mechanics of blood in the stenotic vessel. It is also observed that the fluid velocity and flow rate were reduced when the magnetic field was introduced as well as when its intensity was increased, while WSS was increased with the increase of Hartmann number (Ha) as well as Reynolds number (Re). This work may enhance to work upon the strength of magnetic field to regulate the blood flow in hypertensive patients and those who have blockage in their arteries.A finite element Fluid-Structure-Interaction (FSI) model is developed and validated for hemodynamic pulsatile blood flow through a stenosed artery under the effect of an applied magnetic field. The two-layered blood flow is considered with a core layer of suspension of all erythrocytes assumed to be a non-Newtonian Casson fluid and a peripheral layer of plasma, free from cells, as a Newtonian fluid. The model is considered for the 2D idealized elastic arteries. The blood flow is characterized as a steady, laminar, incompressible and unidirectional flow velocity at the inflow and various values of blood-pressure at the outflow, while the arterial walls as well as the surrounding muscles are modeled as a hyperelastic neo-Hookean material and results are obtained for axial velocities, total flow rate, pressure gradient and wall shear stresses (WSS) and solid displacement due to blood pulse. The result shows significant strengthened WSS at the stenotic regions and weakened WSS at the distal side of stenosis n...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"1 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":"123301079","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}
S. S. Tuly, Md. Momen Shahriar Joarder, M. E. Haque
Pyrolysis is considered as the most promising thermochemical conversion technology for converting solid wastes into liquid fuels. The present work focused on the production of liquid fuel from polythene and PET plastic through pyrolysis process. A fixed bed liquefied petroleum gas (LPG) heating reactor was used to carry out the experiment with diameter 7.6 cm and height 45.6 cm. The pyrolysis of polythene with PET plastic at different blends was carried out at 400-500°C with feed sizes 2cm x 2cm and 1cm x 1cm for polythene and PET plastic respectively. The reactor is heated by means of precisely designed LPG burner. The liquid and char products were collected separately. The addition of polythene into PET plastic in the pyrolysis process not only increased oil yields but also improved oil characteristics. The maximum liquid yield (46%) was obtained from 100% polythene. The maximum heating value for the liquid was found 37500 kJ/kg when 100% polythene was used as feed material.
{"title":"Liquid fuel production by pyrolysis of polythene and PET plastic","authors":"S. S. Tuly, Md. Momen Shahriar Joarder, M. E. Haque","doi":"10.1063/1.5115938","DOIUrl":"https://doi.org/10.1063/1.5115938","url":null,"abstract":"Pyrolysis is considered as the most promising thermochemical conversion technology for converting solid wastes into liquid fuels. The present work focused on the production of liquid fuel from polythene and PET plastic through pyrolysis process. A fixed bed liquefied petroleum gas (LPG) heating reactor was used to carry out the experiment with diameter 7.6 cm and height 45.6 cm. The pyrolysis of polythene with PET plastic at different blends was carried out at 400-500°C with feed sizes 2cm x 2cm and 1cm x 1cm for polythene and PET plastic respectively. The reactor is heated by means of precisely designed LPG burner. The liquid and char products were collected separately. The addition of polythene into PET plastic in the pyrolysis process not only increased oil yields but also improved oil characteristics. The maximum liquid yield (46%) was obtained from 100% polythene. The maximum heating value for the liquid was found 37500 kJ/kg when 100% polythene was used as feed material.","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"1 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":"129631772","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}
P. Vasudevan, P. K. Sen, R. Srivastava, M. Tandon, S. Hegde, T. V. Kumar, P. Davies
Various designs are discussed for ecosystem services in engineered wetlands for contaminated water treatment. Techniques such as Rhizo filtration, Constructed wetlands and Floating rafts are highlighted based on our experiments. Specifically, enhanced bioenergy production by domestic wastewater treatment in rhizo filtration by fast growing trees is discussed. In another set of experiments, designs and factors which can enhance the rate of pollutant removal from wastewater by floating wetlands are seen. In a study extending over three years fast growing short rotation trees, eucalyptus (Eucalyptus hybrid), poplar (Populus deltoides), salix (Salix alba) and melia (Melia azedarach) were irrigated with domestic wastewater with ground water as control. It was seen that the calorific value of woody biomass grown using ground water was of the order 17.4-15.6MJ/kg and this was increased by 6.7 to 16% on wastewater irrigation. Thus, besides a significant increase in the yield biomass (2-4 times) there is a concurrent increase in the calorific value of wood, resulting in higher energy output by wastewater irrigation. TGA and FTIR of the samples did not show significant difference between waste water and ground water irrigated biomass. In the floating wetland study Canna indica was taken on floating rafts and the phytoremediation efficiency of the units was examined. Further the floating raft units were integrated with a constructed wetland to form a hybrid system to enhance the overall efficiency in water treatment. Changes in waste water characteristics with contact time were examined. Reduction in BOD and COD of waste water significant in 2-5 days of contact and this varies with the maturity and density of plants and roots. There is a significant reduction in bacterial load in terms of E. coli counts in parallel with BOD. Rate of reduction of contaminants is near first order. The dissolved oxygen (DO) levels increase with time.Various designs are discussed for ecosystem services in engineered wetlands for contaminated water treatment. Techniques such as Rhizo filtration, Constructed wetlands and Floating rafts are highlighted based on our experiments. Specifically, enhanced bioenergy production by domestic wastewater treatment in rhizo filtration by fast growing trees is discussed. In another set of experiments, designs and factors which can enhance the rate of pollutant removal from wastewater by floating wetlands are seen. In a study extending over three years fast growing short rotation trees, eucalyptus (Eucalyptus hybrid), poplar (Populus deltoides), salix (Salix alba) and melia (Melia azedarach) were irrigated with domestic wastewater with ground water as control. It was seen that the calorific value of woody biomass grown using ground water was of the order 17.4-15.6MJ/kg and this was increased by 6.7 to 16% on wastewater irrigation. Thus, besides a significant increase in the yield biomass (2-4 times) there is a concurr...
{"title":"Ecosystem services by wetlands for polluted water treatment","authors":"P. Vasudevan, P. K. Sen, R. Srivastava, M. Tandon, S. Hegde, T. V. Kumar, P. Davies","doi":"10.1063/1.5115973","DOIUrl":"https://doi.org/10.1063/1.5115973","url":null,"abstract":"Various designs are discussed for ecosystem services in engineered wetlands for contaminated water treatment. Techniques such as Rhizo filtration, Constructed wetlands and Floating rafts are highlighted based on our experiments. Specifically, enhanced bioenergy production by domestic wastewater treatment in rhizo filtration by fast growing trees is discussed. In another set of experiments, designs and factors which can enhance the rate of pollutant removal from wastewater by floating wetlands are seen. In a study extending over three years fast growing short rotation trees, eucalyptus (Eucalyptus hybrid), poplar (Populus deltoides), salix (Salix alba) and melia (Melia azedarach) were irrigated with domestic wastewater with ground water as control. It was seen that the calorific value of woody biomass grown using ground water was of the order 17.4-15.6MJ/kg and this was increased by 6.7 to 16% on wastewater irrigation. Thus, besides a significant increase in the yield biomass (2-4 times) there is a concurrent increase in the calorific value of wood, resulting in higher energy output by wastewater irrigation. TGA and FTIR of the samples did not show significant difference between waste water and ground water irrigated biomass. In the floating wetland study Canna indica was taken on floating rafts and the phytoremediation efficiency of the units was examined. Further the floating raft units were integrated with a constructed wetland to form a hybrid system to enhance the overall efficiency in water treatment. Changes in waste water characteristics with contact time were examined. Reduction in BOD and COD of waste water significant in 2-5 days of contact and this varies with the maturity and density of plants and roots. There is a significant reduction in bacterial load in terms of E. coli counts in parallel with BOD. Rate of reduction of contaminants is near first order. The dissolved oxygen (DO) levels increase with time.Various designs are discussed for ecosystem services in engineered wetlands for contaminated water treatment. Techniques such as Rhizo filtration, Constructed wetlands and Floating rafts are highlighted based on our experiments. Specifically, enhanced bioenergy production by domestic wastewater treatment in rhizo filtration by fast growing trees is discussed. In another set of experiments, designs and factors which can enhance the rate of pollutant removal from wastewater by floating wetlands are seen. In a study extending over three years fast growing short rotation trees, eucalyptus (Eucalyptus hybrid), poplar (Populus deltoides), salix (Salix alba) and melia (Melia azedarach) were irrigated with domestic wastewater with ground water as control. It was seen that the calorific value of woody biomass grown using ground water was of the order 17.4-15.6MJ/kg and this was increased by 6.7 to 16% on wastewater irrigation. Thus, besides a significant increase in the yield biomass (2-4 times) there is a concurr...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"3 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":"129841517","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}
Effects of velocity and fuel concentration oscillations on premixed flames are discussed. Methane/air premixed flame is formed in a wall stagnating flow. The velocity oscillation is imposed to the flow with 𝛷=0.7 by an oscillator with single cylinder-piston unit. The equivalence ratio oscillation is imposed by an oscillator with two cylinder-piston units. The methane/air mixture with the equivalence ratio 𝛷=1.0 is supplied to one unit and that 𝛷=0.4 is supplied to the other unit. Pistons move with 180 degree phase difference which creates a sinusoidal equivalence ratio oscillation keeping the volume flow rate constant. Two oscillators are driven by a single DC motor to ensure complete synchronization. Phase difference between velocity oscillation and equivalence ratio oscillation is set by changing the relative position of pulley teeth of two oscillators. The oscillator frequency varies between 2 Hz and 20 Hz, which means that the oscillation wavelengths are much longer than the flame thickness. The flame motion was recorded by a high-speed video camera. Results showed that the amplitude of the flame motion was a linear superposition of the flame motion by the velocity oscillation and the equivalence ratio oscillation, indicating that each oscillation affects the flame motion independently.Effects of velocity and fuel concentration oscillations on premixed flames are discussed. Methane/air premixed flame is formed in a wall stagnating flow. The velocity oscillation is imposed to the flow with 𝛷=0.7 by an oscillator with single cylinder-piston unit. The equivalence ratio oscillation is imposed by an oscillator with two cylinder-piston units. The methane/air mixture with the equivalence ratio 𝛷=1.0 is supplied to one unit and that 𝛷=0.4 is supplied to the other unit. Pistons move with 180 degree phase difference which creates a sinusoidal equivalence ratio oscillation keeping the volume flow rate constant. Two oscillators are driven by a single DC motor to ensure complete synchronization. Phase difference between velocity oscillation and equivalence ratio oscillation is set by changing the relative position of pulley teeth of two oscillators. The oscillator frequency varies between 2 Hz and 20 Hz, which means that the oscillation wavelengths are much longer than the flame thickness. The flame...
{"title":"Effects of velocity and fuel concentration oscillations on premixed flames","authors":"T. Ueda, Y. Niwa","doi":"10.1063/1.5115845","DOIUrl":"https://doi.org/10.1063/1.5115845","url":null,"abstract":"Effects of velocity and fuel concentration oscillations on premixed flames are discussed. Methane/air premixed flame is formed in a wall stagnating flow. The velocity oscillation is imposed to the flow with 𝛷=0.7 by an oscillator with single cylinder-piston unit. The equivalence ratio oscillation is imposed by an oscillator with two cylinder-piston units. The methane/air mixture with the equivalence ratio 𝛷=1.0 is supplied to one unit and that 𝛷=0.4 is supplied to the other unit. Pistons move with 180 degree phase difference which creates a sinusoidal equivalence ratio oscillation keeping the volume flow rate constant. Two oscillators are driven by a single DC motor to ensure complete synchronization. Phase difference between velocity oscillation and equivalence ratio oscillation is set by changing the relative position of pulley teeth of two oscillators. The oscillator frequency varies between 2 Hz and 20 Hz, which means that the oscillation wavelengths are much longer than the flame thickness. The flame motion was recorded by a high-speed video camera. Results showed that the amplitude of the flame motion was a linear superposition of the flame motion by the velocity oscillation and the equivalence ratio oscillation, indicating that each oscillation affects the flame motion independently.Effects of velocity and fuel concentration oscillations on premixed flames are discussed. Methane/air premixed flame is formed in a wall stagnating flow. The velocity oscillation is imposed to the flow with 𝛷=0.7 by an oscillator with single cylinder-piston unit. The equivalence ratio oscillation is imposed by an oscillator with two cylinder-piston units. The methane/air mixture with the equivalence ratio 𝛷=1.0 is supplied to one unit and that 𝛷=0.4 is supplied to the other unit. Pistons move with 180 degree phase difference which creates a sinusoidal equivalence ratio oscillation keeping the volume flow rate constant. Two oscillators are driven by a single DC motor to ensure complete synchronization. Phase difference between velocity oscillation and equivalence ratio oscillation is set by changing the relative position of pulley teeth of two oscillators. The oscillator frequency varies between 2 Hz and 20 Hz, which means that the oscillation wavelengths are much longer than the flame thickness. The flame...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"191 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":"133714471","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}
Nirupom Das Dipto, Syed Tafheem Ahmed Anik, A. Hasan
The flow behavior and performance parameters of a diffuser-nozzle element of a valveless micropump have been studied for different peak pressures by numerical analysis. Blood, a non-Newtonian fluid material has been taken as the working fluid of which viscosity is modeled by the Carreau Model. A pulsating pressure imposed at the boundary of the element results in a net flow in the diffuser direction due to the dynamic effect. The variation of performance parameters such as net volume flow rate, rectification capability and diffuser efficiency have been observed for quantitative study. Flow behavior and recirculation region have been studied as qualitative study. A 2-D geometry is considered for the numerical analysis and peak pressure has been varied from 5 to 50 kPa for the present study. Net volume flow, rectification capability and diffuser efficiency are found to increase with the increase of peak pressure. Flow separation and recirculation region are found to last for longer period of time with the increase of peak pressure.The flow behavior and performance parameters of a diffuser-nozzle element of a valveless micropump have been studied for different peak pressures by numerical analysis. Blood, a non-Newtonian fluid material has been taken as the working fluid of which viscosity is modeled by the Carreau Model. A pulsating pressure imposed at the boundary of the element results in a net flow in the diffuser direction due to the dynamic effect. The variation of performance parameters such as net volume flow rate, rectification capability and diffuser efficiency have been observed for quantitative study. Flow behavior and recirculation region have been studied as qualitative study. A 2-D geometry is considered for the numerical analysis and peak pressure has been varied from 5 to 50 kPa for the present study. Net volume flow, rectification capability and diffuser efficiency are found to increase with the increase of peak pressure. Flow separation and recirculation region are found to last for longer period of time with the i...
{"title":"A numerical analysis of non-Newtonian fluid flow through a valveless micropump","authors":"Nirupom Das Dipto, Syed Tafheem Ahmed Anik, A. Hasan","doi":"10.1063/1.5115935","DOIUrl":"https://doi.org/10.1063/1.5115935","url":null,"abstract":"The flow behavior and performance parameters of a diffuser-nozzle element of a valveless micropump have been studied for different peak pressures by numerical analysis. Blood, a non-Newtonian fluid material has been taken as the working fluid of which viscosity is modeled by the Carreau Model. A pulsating pressure imposed at the boundary of the element results in a net flow in the diffuser direction due to the dynamic effect. The variation of performance parameters such as net volume flow rate, rectification capability and diffuser efficiency have been observed for quantitative study. Flow behavior and recirculation region have been studied as qualitative study. A 2-D geometry is considered for the numerical analysis and peak pressure has been varied from 5 to 50 kPa for the present study. Net volume flow, rectification capability and diffuser efficiency are found to increase with the increase of peak pressure. Flow separation and recirculation region are found to last for longer period of time with the increase of peak pressure.The flow behavior and performance parameters of a diffuser-nozzle element of a valveless micropump have been studied for different peak pressures by numerical analysis. Blood, a non-Newtonian fluid material has been taken as the working fluid of which viscosity is modeled by the Carreau Model. A pulsating pressure imposed at the boundary of the element results in a net flow in the diffuser direction due to the dynamic effect. The variation of performance parameters such as net volume flow rate, rectification capability and diffuser efficiency have been observed for quantitative study. Flow behavior and recirculation region have been studied as qualitative study. A 2-D geometry is considered for the numerical analysis and peak pressure has been varied from 5 to 50 kPa for the present study. Net volume flow, rectification capability and diffuser efficiency are found to increase with the increase of peak pressure. Flow separation and recirculation region are found to last for longer period of time with the i...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"57 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":"125209343","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. Kharshiduzzaman, M. S. Hossain, Sazid Ali, Soumik Ahmed
Thermal conductivity is one of the most important properties for engineering applications. In order to find out the conductivity of poor conductors, the material under investigation cannot be used ...
导热系数是工程应用中最重要的性能之一。为了找出不良导体的导电性，不能使用所研究的材料。
{"title":"Determination of the thermal conductivity of poor conductive materials in the form of disc by self-constructed Lee’s disc apparatus","authors":"M. Kharshiduzzaman, M. S. Hossain, Sazid Ali, Soumik Ahmed","doi":"10.1063/1.5115959","DOIUrl":"https://doi.org/10.1063/1.5115959","url":null,"abstract":"Thermal conductivity is one of the most important properties for engineering applications. In order to find out the conductivity of poor conductors, the material under investigation cannot be used ...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"32 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":"125868913","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 design and operation of high-performance combustion systems to meet current and future propulsion requirements face overarching technical challenges from our finite understanding of turbulent combustion. Propulsion systems will continue to operate with flames stabilized at high Reynolds numbers in complex burner geometries, such as swirl-stabilized flames in the main combustor of gas-turbine engines. High-Reynolds-number turbulent combustion, however, is inherently a “four-dimensional” (4D) — three dimensional (3D) in space and dynamic in time—phenomenon that accesses a wide range of both length and time scales. These length scales range from meters to microns with temporal dynamics occurring at frequencies from ∼100 Hz—associated with thermoacoustic instabilities—to 100 kHz or higher, as in the case of emerging detonation-engine technologies and other advanced propulsion and reacting-flow systems. Moreover, understanding the complex interplay between underlying turbulent fluid dynamics and combustion chemistry requires multi-dimensional diagnostics that allow simultaneous measurement of multiple physicochemical parameters, such as temperature and chemical-species concentrations. Unfortunately, combustion diagnostics have not traditionally offered kHz data rates for measurements in the 3D spatial domain, as is required to resolve the spatio-temporal dynamics of turbulent combustion processes. Recent developments in burst-mode laser technology, however, are now paving the way toward 4D measurement capabilities at dynamic rates of hundreds of kHz and potentially into the MHz regime. This paper will focus on the recent developments of lasers and imaging systems that portend unprecedented transformative approaches for characterizing the three-dimensional evolution of highly complex phenomena in reacting and non-reacting flows. Such phenomena, which control the performances of various propulsion systems, are inherently difficult to study because they evolve at ultrafast time scales and span an extremely wide range of temperatures and pressures, often under optically dense conditions. They include, but are not limited to, turbulence–chemistry interactions in gas-turbine, rocket, and pressure-gain combustion systems; detonation physics and dense particle aerodynamics in explosive munitions; and shock/boundary-layer interactions in other propulsion systems.The design and operation of high-performance combustion systems to meet current and future propulsion requirements face overarching technical challenges from our finite understanding of turbulent combustion. Propulsion systems will continue to operate with flames stabilized at high Reynolds numbers in complex burner geometries, such as swirl-stabilized flames in the main combustor of gas-turbine engines. High-Reynolds-number turbulent combustion, however, is inherently a “four-dimensional” (4D) — three dimensional (3D) in space and dynamic in time—phenomenon that accesses a wide range of both lengt
{"title":"4D imaging of fast flow dynamics: From challenging dream to reality","authors":"S. Roy, N. Jiang, P. Hsu, H. Stauffer","doi":"10.1063/1.5115843","DOIUrl":"https://doi.org/10.1063/1.5115843","url":null,"abstract":"The design and operation of high-performance combustion systems to meet current and future propulsion requirements face overarching technical challenges from our finite understanding of turbulent combustion. Propulsion systems will continue to operate with flames stabilized at high Reynolds numbers in complex burner geometries, such as swirl-stabilized flames in the main combustor of gas-turbine engines. High-Reynolds-number turbulent combustion, however, is inherently a “four-dimensional” (4D) — three dimensional (3D) in space and dynamic in time—phenomenon that accesses a wide range of both length and time scales. These length scales range from meters to microns with temporal dynamics occurring at frequencies from ∼100 Hz—associated with thermoacoustic instabilities—to 100 kHz or higher, as in the case of emerging detonation-engine technologies and other advanced propulsion and reacting-flow systems. Moreover, understanding the complex interplay between underlying turbulent fluid dynamics and combustion chemistry requires multi-dimensional diagnostics that allow simultaneous measurement of multiple physicochemical parameters, such as temperature and chemical-species concentrations. Unfortunately, combustion diagnostics have not traditionally offered kHz data rates for measurements in the 3D spatial domain, as is required to resolve the spatio-temporal dynamics of turbulent combustion processes. Recent developments in burst-mode laser technology, however, are now paving the way toward 4D measurement capabilities at dynamic rates of hundreds of kHz and potentially into the MHz regime. This paper will focus on the recent developments of lasers and imaging systems that portend unprecedented transformative approaches for characterizing the three-dimensional evolution of highly complex phenomena in reacting and non-reacting flows. Such phenomena, which control the performances of various propulsion systems, are inherently difficult to study because they evolve at ultrafast time scales and span an extremely wide range of temperatures and pressures, often under optically dense conditions. They include, but are not limited to, turbulence–chemistry interactions in gas-turbine, rocket, and pressure-gain combustion systems; detonation physics and dense particle aerodynamics in explosive munitions; and shock/boundary-layer interactions in other propulsion systems.The design and operation of high-performance combustion systems to meet current and future propulsion requirements face overarching technical challenges from our finite understanding of turbulent combustion. Propulsion systems will continue to operate with flames stabilized at high Reynolds numbers in complex burner geometries, such as swirl-stabilized flames in the main combustor of gas-turbine engines. High-Reynolds-number turbulent combustion, however, is inherently a “four-dimensional” (4D) — three dimensional (3D) in space and dynamic in time—phenomenon that accesses a wide range of both lengt","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"1 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":"130314383","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}
Md. Insiat Islam Rabby, Md. Ehsanul Hasan, Abdullah Al Amin, A. Islam
A numerical study of convective heat transfer in the developing region of a pipe for laminar flow using nanofluids is presented. The finite volume method is used to solve the transport equations fo...
利用纳米流体对层流管道展开区的对流换热进行了数值研究。用有限体积法求解了…
{"title":"Laminar convective heat transfer in developing region of a pipe by using nanofluids","authors":"Md. Insiat Islam Rabby, Md. Ehsanul Hasan, Abdullah Al Amin, A. Islam","doi":"10.1063/1.5115921","DOIUrl":"https://doi.org/10.1063/1.5115921","url":null,"abstract":"A numerical study of convective heat transfer in the developing region of a pipe for laminar flow using nanofluids is presented. The finite volume method is used to solve the transport equations fo...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"1 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":"122622929","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}
Thermoacoustic science focuses on the interaction between sound energy and heat energy and the thermoacoustic refrigeration system uses sound wave to attain a temperature gradient along a porous solid medium (stack). It is an emerging technology to replace conventional refrigeration system with the benefit of having no moving parts. In the present study, the effects of the material, length, and position of the stack inside the resonator tube on cooling effect across the stack are examined. Three different materials-nylon, ABS plastic and wood are used as stack material which yield a cooling effect in the range of 2-5°C across the resonator tube (length of 60 cm) depending upon the stack position at resonant frequency (145 Hz). Three samples of each stack (length of 3, 6, and 9 cm) are placed at a spacing of 10 cm inside the resonator tube. Operating frequency is constant at 145 Hz which is resonant frequency. Highest temperature difference is obtained for ABS plastic stack of 3 cm length at the closed end of the tube at resonant frequency. The maximum cooling load is observed at the closed end of resonator tube, but the coefficient of performance (COP) is found to be maximum at the open end (driver end) of the tube. The performance of the thermoacoustic system is numerically analyzed using DeltaEC software for the same set of operating conditions and is compared with the experimental findings.Thermoacoustic science focuses on the interaction between sound energy and heat energy and the thermoacoustic refrigeration system uses sound wave to attain a temperature gradient along a porous solid medium (stack). It is an emerging technology to replace conventional refrigeration system with the benefit of having no moving parts. In the present study, the effects of the material, length, and position of the stack inside the resonator tube on cooling effect across the stack are examined. Three different materials-nylon, ABS plastic and wood are used as stack material which yield a cooling effect in the range of 2-5°C across the resonator tube (length of 60 cm) depending upon the stack position at resonant frequency (145 Hz). Three samples of each stack (length of 3, 6, and 9 cm) are placed at a spacing of 10 cm inside the resonator tube. Operating frequency is constant at 145 Hz which is resonant frequency. Highest temperature difference is obtained for ABS plastic stack of 3 cm length at the closed end...
{"title":"Combined experimental and numerical study on the performance of thermoacoustic refrigeration system","authors":"M. Khan, Tahmid Rakin Siddiqui, M. Rahman","doi":"10.1063/1.5115867","DOIUrl":"https://doi.org/10.1063/1.5115867","url":null,"abstract":"Thermoacoustic science focuses on the interaction between sound energy and heat energy and the thermoacoustic refrigeration system uses sound wave to attain a temperature gradient along a porous solid medium (stack). It is an emerging technology to replace conventional refrigeration system with the benefit of having no moving parts. In the present study, the effects of the material, length, and position of the stack inside the resonator tube on cooling effect across the stack are examined. Three different materials-nylon, ABS plastic and wood are used as stack material which yield a cooling effect in the range of 2-5°C across the resonator tube (length of 60 cm) depending upon the stack position at resonant frequency (145 Hz). Three samples of each stack (length of 3, 6, and 9 cm) are placed at a spacing of 10 cm inside the resonator tube. Operating frequency is constant at 145 Hz which is resonant frequency. Highest temperature difference is obtained for ABS plastic stack of 3 cm length at the closed end of the tube at resonant frequency. The maximum cooling load is observed at the closed end of resonator tube, but the coefficient of performance (COP) is found to be maximum at the open end (driver end) of the tube. The performance of the thermoacoustic system is numerically analyzed using DeltaEC software for the same set of operating conditions and is compared with the experimental findings.Thermoacoustic science focuses on the interaction between sound energy and heat energy and the thermoacoustic refrigeration system uses sound wave to attain a temperature gradient along a porous solid medium (stack). It is an emerging technology to replace conventional refrigeration system with the benefit of having no moving parts. In the present study, the effects of the material, length, and position of the stack inside the resonator tube on cooling effect across the stack are examined. Three different materials-nylon, ABS plastic and wood are used as stack material which yield a cooling effect in the range of 2-5°C across the resonator tube (length of 60 cm) depending upon the stack position at resonant frequency (145 Hz). Three samples of each stack (length of 3, 6, and 9 cm) are placed at a spacing of 10 cm inside the resonator tube. Operating frequency is constant at 145 Hz which is resonant frequency. Highest temperature difference is obtained for ABS plastic stack of 3 cm length at the closed end...","PeriodicalId":423885,"journal":{"name":"8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING","volume":"129 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":"123043539","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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