In this study, a medium frequency power transformer has been designed analytically and its sizes have been obtained. The transformer’s analyses were made numerically by 2D AnsysMaxwell Solver software package. The Solver has also helped to study suitable transformer core and winding samples. Unlike medium frequency transformer, which is generally driven by unipolar PWM method, the designed transformer is driven by bipolar PWM method in the study. The core losses were obtained for different core materials (Trafoperm N3 and Amorfous 2605SA1) by AnsysMaxwell numerical and analytical calculations. The calculated losses for no-load working conditions were compared with each other. The designed transformer has been analyzed for its noload and loaded working conditions magnetically. Finally, the radial and axial forces created in the windings have also been examined for loaded working condition.
{"title":"A medium frequency transformer design for spot welding machine using sizing equation and finite element analysis","authors":"S. Arslan, I. Tarimer, M. E. Güven, S. A. Oy","doi":"10.30765/er.40.3.05","DOIUrl":"https://doi.org/10.30765/er.40.3.05","url":null,"abstract":"In this study, a medium frequency power transformer has been designed analytically and its sizes have been obtained. The transformer’s analyses were made numerically by 2D AnsysMaxwell Solver software package. The Solver has also helped to study suitable transformer core and winding samples. Unlike medium frequency transformer, which is generally driven by unipolar PWM method, the designed transformer is driven by bipolar PWM method in the study. The core losses were obtained for different core materials (Trafoperm N3 and Amorfous 2605SA1) by AnsysMaxwell numerical and analytical calculations. The calculated losses for no-load working conditions were compared with each other. The designed transformer has been analyzed for its noload and loaded working conditions magnetically. Finally, the radial and axial forces created in the windings have also been examined for loaded working condition.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.3.05","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45018887","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}
Nowadays, experts believe there are abundant sources of risks in a supply chain. An important group of risks against a supply chain is the disruption risks group, which disturbs the flow of material in the chain and may lead to inefficiency in providing the final product in the supply chain. The aim of this article is to investigate the control of costs of disruption in a supply chain by considering the possibility of disruption. In fact, this research focuses on determining the best combination of suppliers and quota allocation with regards to disruption in suppliers. The proposed multi-objective mathematical model in this paper is a mixed-integer programming (MIP) model with objective functions to minimize transaction costs of suppliers, expected costs of purchasing goods, expected percentages of delayed products, expected returned products, and to maximize expected evaluation scores of the selected suppliers. Due to the uncertainty of demand and supplier disruption in the real world, their values are also considered uncertain; the proposed multi-objective model is studied by using a scenario-based stochastic programming (SP) method. In this method, all possible predictions for demand and disruption values are simultaneously included in the model; objective function results have more optimal value than a separate solution of the model for each predicted value.
{"title":"Solving multi-objective supplier selection and quota allocation problem under disruption using a scenario-based approach","authors":"Farnaz Javadi Gargari, M. Seifbarghy","doi":"10.30765/er.40.3.08","DOIUrl":"https://doi.org/10.30765/er.40.3.08","url":null,"abstract":"Nowadays, experts believe there are abundant sources of risks in a supply chain. An important group of risks against a supply chain is the disruption risks group, which disturbs the flow of material in the chain and may lead to inefficiency in providing the final product in the supply chain. The aim of this article is to investigate the control of costs of disruption in a supply chain by considering the possibility of disruption. In fact, this research focuses on determining the best combination of suppliers and quota allocation with regards to disruption in suppliers. The proposed multi-objective mathematical model in this paper is a mixed-integer programming (MIP) model with objective functions to minimize transaction costs of suppliers, expected costs of purchasing goods, expected percentages of delayed products, expected returned products, and to maximize expected evaluation scores of the selected suppliers. Due to the uncertainty of demand and supplier disruption in the real world, their values are also considered uncertain; the proposed multi-objective model is studied by using a scenario-based stochastic programming (SP) method. In this method, all possible predictions for demand and disruption values are simultaneously included in the model; objective function results have more optimal value than a separate solution of the model for each predicted value.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.3.08","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44368697","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}
T. Lenkovskiy, A. Glazov, V. Kulyk, Z. Duriagina, A. Dzyubyk, R. Kovalchuk, Volodymyr Topilnytskyy, L. Dzyubyk, V. Vira
An effective theoretical-experimental approach to evaluation of wheel steels resistance to contactfatigue damage (spalling) formation by pitting mechanism is proposed. On the base of the results of experimental studies and calculations, the contact-fatigue life curve of high-tempered 65Г steel is built. The results are similar and compared to a model low-tempered 75ХГСТ steel.
{"title":"A new approach for evaluating the resistance of wheel steel to spall formation","authors":"T. Lenkovskiy, A. Glazov, V. Kulyk, Z. Duriagina, A. Dzyubyk, R. Kovalchuk, Volodymyr Topilnytskyy, L. Dzyubyk, V. Vira","doi":"10.30765/er.40.2.08","DOIUrl":"https://doi.org/10.30765/er.40.2.08","url":null,"abstract":"An effective theoretical-experimental approach to evaluation of wheel steels resistance to contactfatigue damage (spalling) formation by pitting mechanism is proposed. On the base of the results of experimental studies and calculations, the contact-fatigue life curve of high-tempered 65Г steel is built. The results are similar and compared to a model low-tempered 75ХГСТ steel.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.2.08","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48022772","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. A. Dare, E. O. Ige, Olukunle Cornelius Akinpelu
Common techniques employed to minimize ignition energy of gaseous fuels in micro reactors such as the use of catalyst are being plagued with setbacks. This report demonstrates the use of electric field to sustain combustion, minimize heat loss and enhance reactant mixing in microchannels of varying geometries. We set two defining constructal parameters for serpentine and straight microchannels of 0.05 to 0.25 to investigate geometric effect on the mixing of the reactants. Inlet concentration of propane and oxygen was set at 0.15 mol/dm3 and 0.7 mol/dm3 respectively. Reynolds numbers 400, 470, 530, 600 and 670 corresponding to inlet velocities of 0.06 m/s, 0.07 m/s, 0.08 m/s, 0.09 m/s and 0.1 m/s were used in the straight channel to study the dependence of reaction rate, temperature drop and reactants diffusion on the combustion process. We report that at an inlet temperature of 500 K which was below the propane’s auto ignition temperature of 743 K, the reaction could occur in the presence of a 50 V applied voltage. Increasing constructual parameter (β) yielded an increase in reaction rate and a decrease in temperature drop. At the same constructual parameter, the serpentine geometry displayed a better result with the peak reaction rate of 894 mol/m3s. More so, increase in the Reynolds number and shape factor for the two geometries led to an increase in reaction rate and propane consumption. These findings could be suitably beneficial to provide minimal fuel requirement for miniaturized vehicles and micro-heat engines
{"title":"Auto-ignition performance of an electrified microreactor with constructal geometries","authors":"A. A. Dare, E. O. Ige, Olukunle Cornelius Akinpelu","doi":"10.30765/ER.40.2.06","DOIUrl":"https://doi.org/10.30765/ER.40.2.06","url":null,"abstract":"Common techniques employed to minimize ignition energy of gaseous fuels in micro reactors such as the use of catalyst are being plagued with setbacks. This report demonstrates the use of electric field to sustain combustion, minimize heat loss and enhance reactant mixing in microchannels of varying geometries. We set two defining constructal parameters for serpentine and straight microchannels of 0.05 to 0.25 to investigate geometric effect on the mixing of the reactants. Inlet concentration of propane and oxygen was set at 0.15 mol/dm3 and 0.7 mol/dm3 respectively. Reynolds numbers 400, 470, 530, 600 and 670 corresponding to inlet velocities of 0.06 m/s, 0.07 m/s, 0.08 m/s, 0.09 m/s and 0.1 m/s were used in the straight channel to study the dependence of reaction rate, temperature drop and reactants diffusion on the combustion process. We report that at an inlet temperature of 500 K which was below the propane’s auto ignition temperature of 743 K, the reaction could occur in the presence of a 50 V applied voltage. Increasing constructual parameter (β) yielded an increase in reaction rate and a decrease in temperature drop. At the same constructual parameter, the serpentine geometry displayed a better result with the peak reaction rate of 894 mol/m3s. More so, increase in the Reynolds number and shape factor for the two geometries led to an increase in reaction rate and propane consumption. These findings could be suitably beneficial to provide minimal fuel requirement for miniaturized vehicles and micro-heat engines","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/ER.40.2.06","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45543779","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 effects of wind on beam bridges can be significantly reduced with careful design of deck, roadway and wind barriers, as well as with appropriate design of piers. In this paper, the influence of corner design of rectangular cross-sectional piers to total wind force on piers is investigated. The total wind force changes, due to a different corner design of rectangular cross section of piers in free standing phase, are analyzed for piers of different heights, different environments and different wind velocities. The correlation between changes in total wind force and changes in geometric properties of a pier is also shown. By rounding the corners of a pier square cross section, the total wind force on pier in free standing phase can be drastically reduced in comparison to the total wind force on sharp corner pier with a small reduction in a load bearing properties of the pier. Changes in the bridge pier environment, as well as changes in pier height and wind velocity have negligible influence on changes in reduction of total wind force due to rounding the pier corners.
{"title":"Reduction in wind force in relation to corner design of bridge piers","authors":"Ivana Štimac Grandić, D. Grandic","doi":"10.30765/er.40.2.10","DOIUrl":"https://doi.org/10.30765/er.40.2.10","url":null,"abstract":"The effects of wind on beam bridges can be significantly reduced with careful design of deck, roadway and wind barriers, as well as with appropriate design of piers. In this paper, the influence of corner design of rectangular cross-sectional piers to total wind force on piers is investigated. The total wind force changes, due to a different corner design of rectangular cross section of piers in free standing phase, are analyzed for piers of different heights, different environments and different wind velocities. The correlation between changes in total wind force and changes in geometric properties of a pier is also shown. By rounding the corners of a pier square cross section, the total wind force on pier in free standing phase can be drastically reduced in comparison to the total wind force on sharp corner pier with a small reduction in a load bearing properties of the pier. Changes in the bridge pier environment, as well as changes in pier height and wind velocity have negligible influence on changes in reduction of total wind force due to rounding the pier corners.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.2.10","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44052548","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}
C. Fapohunda, H. Bello, Taiwo Salako, Suaib Tijani
This paper presents the results of investigation conducted to evaluate structural performance of lateritic concrete containing palm kernel shell (PKS) as partial replacement of coarse aggregate by weight. The properties evaluated were: workability, density, compressive strength, microstructure, sorptivity, and water absorption of lateritic concrete with PKS specimens. The coarse aggregate fraction of the lateritic concrete was partially replaced with PKS of up to 50% at interval of 10% by weight. The results showed that: (i) the use of PKS to partially replace the coarse aggregate in lateritic concrete resulted in harsh concrete with low workabilities, (ii) lateritic concrete with PKS as partial replacement of coarse aggregate of up to 50% developed densities that can be used for normal concrete application, (iii) lateritic concrete with PKS as partial replacement of coarse aggregate of up to 10% developed strength that is comparable to the specimens without PKS, (iv) the SEM images of lateritic concrete samples showed a progressively porous internal structure with PKS and (v) lateritic concrete with PKS as partial replacement of coarse aggregate results in porous material but became less porous at longer curing ages. It can be concluded from these results that the replacement of the coarse aggregate constituent with PKS by weight not exceeding 10%, in the production of lateritic concrete, resulted in a material with satisfactory structural performance.
{"title":"Strength, micro-structure & durability investigations of lateritic concrete with palm kernel shell (PKS) as partial replacement of coarse aggregates","authors":"C. Fapohunda, H. Bello, Taiwo Salako, Suaib Tijani","doi":"10.30765/ER.40.2.07","DOIUrl":"https://doi.org/10.30765/ER.40.2.07","url":null,"abstract":"This paper presents the results of investigation conducted to evaluate structural performance of lateritic concrete containing palm kernel shell (PKS) as partial replacement of coarse aggregate by weight. The properties evaluated were: workability, density, compressive strength, microstructure, sorptivity, and water absorption of lateritic concrete with PKS specimens. The coarse aggregate fraction of the lateritic concrete was partially replaced with PKS of up to 50% at interval of 10% by weight. The results showed that: (i) the use of PKS to partially replace the coarse aggregate in lateritic concrete resulted in harsh concrete with low workabilities, (ii) lateritic concrete with PKS as partial replacement of coarse aggregate of up to 50% developed densities that can be used for normal concrete application, (iii) lateritic concrete with PKS as partial replacement of coarse aggregate of up to 10% developed strength that is comparable to the specimens without PKS, (iv) the SEM images of lateritic concrete samples showed a progressively porous internal structure with PKS and (v) lateritic concrete with PKS as partial replacement of coarse aggregate results in porous material but became less porous at longer curing ages. It can be concluded from these results that the replacement of the coarse aggregate constituent with PKS by weight not exceeding 10%, in the production of lateritic concrete, resulted in a material with satisfactory structural performance.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47475488","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 study investigates the use of waste glass as filler in asphalt concrete. Waste glass constitutes a significant proportion of the waste generated in both developed and developing countries. Successful utilization of the waste glass in asphalt will reduce the problem faced by environmental agencies at ensuring safe disposal of the non-biodegradable waste and may improve the asphalt properties. In the study, a waste glass in form of a filler was introduced into the asphalt mix at 8%, 10%, 12%, 14%, 16%, 18% and 20% of the total mix. The asphalt concrete samples with and without waste glass as filler were subjected to the Marshall test to determine the stability, flow, air voids, void in mix aggregate and void filled with bitumen. The Marshall test results show that stability increases when increasing glass filler up to 18%, although the values were lower than of the asphalt concrete without waste glass. This implies improved resistance to fatigue for higher waste glass content. Also, the flow increases with increasing glass filler, which implies the resistance to permanent deformation which did not improve. Generally, the introduction of waste glass in the asphalt concrete is environmentally friendly, and it will aid the sustainable management of waste glass.
{"title":"Evaluation of the effects of waste glass in asphalt concrete using the Marshall test","authors":"O. Ogundipe, E. S. Nnochiri","doi":"10.30765/er.40.2.04","DOIUrl":"https://doi.org/10.30765/er.40.2.04","url":null,"abstract":"The study investigates the use of waste glass as filler in asphalt concrete. Waste glass constitutes a significant proportion of the waste generated in both developed and developing countries. Successful utilization of the waste glass in asphalt will reduce the problem faced by environmental agencies at ensuring safe disposal of the non-biodegradable waste and may improve the asphalt properties. In the study, a waste glass in form of a filler was introduced into the asphalt mix at 8%, 10%, 12%, 14%, 16%, 18% and 20% of the total mix. The asphalt concrete samples with and without waste glass as filler were subjected to the Marshall test to determine the stability, flow, air voids, void in mix aggregate and void filled with bitumen. The Marshall test results show that stability increases when increasing glass filler up to 18%, although the values were lower than of the asphalt concrete without waste glass. This implies improved resistance to fatigue for higher waste glass content. Also, the flow increases with increasing glass filler, which implies the resistance to permanent deformation which did not improve. Generally, the introduction of waste glass in the asphalt concrete is environmentally friendly, and it will aid the sustainable management of waste glass.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.2.04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49449988","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 paper gives a review of conditions and triggers in which landslides occur on flysch slopes in central and northern Istria. The north-eastern part of the Istrian Peninsula, the so-called Gray Istria, consists of Paleogene flysch rock mass. Landslides in this area are usually triggered by heavy rainfall together with human activity which changes slope geometry and assists in retaining surface water in the sliding zone. Briefly, hydrogeological conditions in combination with ground water levels and pore water pressures increase, lead to numerous instability phenomena, during the long and continuous rainfall periods. Instabilities usually include small rotational and translational landslides, and it is seldom that debris flows and rock falls occur. Landslides are evenly evidenced in the first part of winter and the early spring time which corresponds to the second rainfall peak. The analyses performed based on landslide documentation and rainfall historical data, show rainfall trends associated with landslide occurrence. Depending on meteorological, hydrological and geological conditions, cumulative rainfall which triggered landslide activation varies inside a three-month period. The results presented show rainfall trends which serve as characteristic landslide triggers on flysch slopes in north-eastern part of Istria.
{"title":"Conditions and triggers of landslides on flysch slopes in Istria, Croatia","authors":"S. Jovancevic, J. Rubinić, Ž. Arbanas","doi":"10.30765/er.40.2.09","DOIUrl":"https://doi.org/10.30765/er.40.2.09","url":null,"abstract":"The paper gives a review of conditions and triggers in which landslides occur on flysch slopes in central and northern Istria. The north-eastern part of the Istrian Peninsula, the so-called Gray Istria, consists of Paleogene flysch rock mass. Landslides in this area are usually triggered by heavy rainfall together with human activity which changes slope geometry and assists in retaining surface water in the sliding zone. Briefly, hydrogeological conditions in combination with ground water levels and pore water pressures increase, lead to numerous instability phenomena, during the long and continuous rainfall periods. Instabilities usually include small rotational and translational landslides, and it is seldom that debris flows and rock falls occur. Landslides are evenly evidenced in the first part of winter and the early spring time which corresponds to the second rainfall peak. The analyses performed based on landslide documentation and rainfall historical data, show rainfall trends associated with landslide occurrence. Depending on meteorological, hydrological and geological conditions, cumulative rainfall which triggered landslide activation varies inside a three-month period. The results presented show rainfall trends which serve as characteristic landslide triggers on flysch slopes in north-eastern part of Istria.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.2.09","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45336578","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. Muminović, Sanjin Braut, Adil Muminović, Isad Saric, Goranka Štimac Rončević
Proportional–integral–derivative (PID) control is the most common control approach used to control active magnetic bearings system, especially in the case of supporting rigid rotors. In the case of flexible rotor support, the most common control is again PID control in combination with notch filters. Other control approaches, known as modern control theory, are still in development process and cannot be commonly found in real life industrial application. Right now, they are mostly used in research applications. In comparison to PID control, PI-D control implies that derivate element is in feedback loop instead in main branch of the system. In this paper, performances of flexible rotor/active magnetic bearing system were investigated in the case of PID and PI-D control, both in combination with notch filters. The performances of the system were analysed using an analysis in time domain by observing system response to step input and in frequency domain by observing a frequency response of sensitivity function.
{"title":"Improvement of flexible rotor/active magnetic bearings system performance using pi-d control","authors":"A. Muminović, Sanjin Braut, Adil Muminović, Isad Saric, Goranka Štimac Rončević","doi":"10.30765/er.40.2.12","DOIUrl":"https://doi.org/10.30765/er.40.2.12","url":null,"abstract":"Proportional–integral–derivative (PID) control is the most common control approach used to control active magnetic bearings system, especially in the case of supporting rigid rotors. In the case of flexible rotor support, the most common control is again PID control in combination with notch filters. Other control approaches, known as modern control theory, are still in development process and cannot be commonly found in real life industrial application. Right now, they are mostly used in research applications. In comparison to PID control, PI-D control implies that derivate element is in feedback loop instead in main branch of the system. In this paper, performances of flexible rotor/active magnetic bearing system were investigated in the case of PID and PI-D control, both in combination with notch filters. The performances of the system were analysed using an analysis in time domain by observing system response to step input and in frequency domain by observing a frequency response of sensitivity function.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.30765/er.40.2.12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69599023","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 bubble evolution in the liquid titanium melt under vertical centrifugal field has been studied by the hydraulic experiment simulation. The bubble migration process in the simple and complex cavities, the bubble morphology, bubble dimensional size diversification under different mould rotational speed has been investigated. The results show that the mould wall has a blocking effect on the bubble migration. The bubble migration in the simple cavity deviates from the line between the bubble initial position and the rotation shaft of the casting mould. Also, the bubbles in the complex cavity gather, re-nucleate and form new big ones for the blocking effect of the complex geometry shape on the radial movement of the bubble. The shape of bubbles in both the simple and complex cavity during the migration process is not a perfect sphere, but an elliptical shape. The critical size of bubble released from the bubble generation chamber decreases with the increment of the mould rotational speed. The diameter of the gas bubbles in the simple cavity during the migration process become bigger and bigger for the pressure difference at different positions of the cavity in the vertical centrifugal field.
{"title":"Bubble evolution in the titanium alloy melt under vertical centrifugal field","authors":"Qin‐Qin Xu, Xing Wang, Shi-ping Wu","doi":"10.30765/er.40.2.03","DOIUrl":"https://doi.org/10.30765/er.40.2.03","url":null,"abstract":"The bubble evolution in the liquid titanium melt under vertical centrifugal field has been studied by the hydraulic experiment simulation. The bubble migration process in the simple and complex cavities, the bubble morphology, bubble dimensional size diversification under different mould rotational speed has been investigated. The results show that the mould wall has a blocking effect on the bubble migration. The bubble migration in the simple cavity deviates from the line between the bubble initial position and the rotation shaft of the casting mould. Also, the bubbles in the complex cavity gather, re-nucleate and form new big ones for the blocking effect of the complex geometry shape on the radial movement of the bubble. The shape of bubbles in both the simple and complex cavity during the migration process is not a perfect sphere, but an elliptical shape. The critical size of bubble released from the bubble generation chamber decreases with the increment of the mould rotational speed. The diameter of the gas bubbles in the simple cavity during the migration process become bigger and bigger for the pressure difference at different positions of the cavity in the vertical centrifugal field.","PeriodicalId":44022,"journal":{"name":"Engineering Review","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46873978","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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