In non-isothermal flows, heatlines are used to depict the energy flow from a hot surface to a cold surface, and helps in visualising the strength of the convective heat transfer as compared to the conductive heat transfer. Traditionally, researchers have plotted heatlines by solving heat-function equations in their solvers during the runtime. However, this requires access to the solver code and is time consuming to implement. Further, the literature available so far only concerns simple geometric shapes. This work aims to document out-of-the box methods for visualization of heatlines that can be done as a post-processing exercise. A comparison of streamlines and heatlines, is first presented to enhance the understanding of the application of heatlines in heat transfer problems and to use the same technique in post-processing computer programs for visualizing heatlines. The procedures to plot heatlines using commercial (TecPlot and CFD-Post) and open-source (ParaView) tools are presented. Illustrative examples of different computational geometries from past literature are validated to establish the efficacy of the method. Further, the method can be also applied to plot heatlines for complex geometries which is not feasible with the traditional approaches
{"title":"How to Plot Heatlines?","authors":"C. Mukherjee, S. Mukhopadhyay","doi":"10.1115/1.4062954","DOIUrl":"https://doi.org/10.1115/1.4062954","url":null,"abstract":"\u0000 In non-isothermal flows, heatlines are used to depict the energy flow from a hot surface to a cold surface, and helps in visualising the strength of the convective heat transfer as compared to the conductive heat transfer. Traditionally, researchers have plotted heatlines by solving heat-function equations in their solvers during the runtime. However, this requires access to the solver code and is time consuming to implement. Further, the literature available so far only concerns simple geometric shapes. This work aims to document out-of-the box methods for visualization of heatlines that can be done as a post-processing exercise. A comparison of streamlines and heatlines, is first presented to enhance the understanding of the application of heatlines in heat transfer problems and to use the same technique in post-processing computer programs for visualizing heatlines. The procedures to plot heatlines using commercial (TecPlot and CFD-Post) and open-source (ParaView) tools are presented. Illustrative examples of different computational geometries from past literature are validated to establish the efficacy of the method. Further, the method can be also applied to plot heatlines for complex geometries which is not feasible with the traditional approaches","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"97 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89916828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kalina cycle is established as a reliable low-grade energy cycle working on solar, geothermal and other waste heat recovery sources. This work aims to develop a novel methodology for optimizing a Kalina cycle according to the solar irradiation. A comprehensive analysis of performance is conducted by varying the parameters of the Kalina system, modeled with high and low pressure turbines. The present work implements and analyses the performance of a multi turbine Kalina cycle with cylindrical parabolic collectors for energy input at different time, on a particular day, for a location. The proposed cycle is modeled to simulate the working. The dependency of parameters - separator pressure, concentration of ammonia in boiler, intermediate separator temperature and vapor fraction at condenser side turbine exit - on the system performance is investigated. Optimization is conducted using genetic algorithm with net power as objective function for different solar irradiations. The optimized power values are 282.62, 246.75, 222.31 and 180.0 kW for solar influxes 507.7, 461.8, 413.9 and 321.0 W/m 2 respectively. The results show that the proposed model can be adopted for better performance. A thermo – economic analysis of an optimized output is conducted to conclude on capital investment and operation cost for sustainable power production. The analysis yields highest cost rate of exergy destruction of 58936.41$/yr for the boiler. The investment cost the turbines together is 89% of the total capital investment and hence thermo - economic factor is highest for these components.
{"title":"Thermodynamic and Thermo - economic Analysis of a Solar Integrated Double Turbine Kalina Cycle for varying Solar Flux Conditions","authors":"Devi Parvathy S, James Varghese","doi":"10.1115/1.4062922","DOIUrl":"https://doi.org/10.1115/1.4062922","url":null,"abstract":"\u0000 Kalina cycle is established as a reliable low-grade energy cycle working on solar, geothermal and other waste heat recovery sources. This work aims to develop a novel methodology for optimizing a Kalina cycle according to the solar irradiation. A comprehensive analysis of performance is conducted by varying the parameters of the Kalina system, modeled with high and low pressure turbines. The present work implements and analyses the performance of a multi turbine Kalina cycle with cylindrical parabolic collectors for energy input at different time, on a particular day, for a location. The proposed cycle is modeled to simulate the working. The dependency of parameters - separator pressure, concentration of ammonia in boiler, intermediate separator temperature and vapor fraction at condenser side turbine exit - on the system performance is investigated. Optimization is conducted using genetic algorithm with net power as objective function for different solar irradiations. The optimized power values are 282.62, 246.75, 222.31 and 180.0 kW for solar influxes 507.7, 461.8, 413.9 and 321.0 W/m 2 respectively. The results show that the proposed model can be adopted for better performance. A thermo – economic analysis of an optimized output is conducted to conclude on capital investment and operation cost for sustainable power production. The analysis yields highest cost rate of exergy destruction of 58936.41$/yr for the boiler. The investment cost the turbines together is 89% of the total capital investment and hence thermo - economic factor is highest for these components.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"76 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86438652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A comprehensive computational study for the assessment of a horizontal solar calciner is presented. The heat and mass transfer models that have been developed give valuable insight and enlighten the fundamental principles that rule the solar-aided CaCO3 decomposition. The obtained computational data are appropriately interpreted and serve as guidelines in order to establish the operational framework of the solar reactor. Additionally, this set of predictive models identifies the optimum values of the key parameters that boost the performance of the process. The models have been validated comparing the computational results with the experimental data and the calciner performance is evaluated considering the overall process efficiency.
{"title":"Computational assessment of a novel solar calciner","authors":"M. Syrigou","doi":"10.1115/1.4062921","DOIUrl":"https://doi.org/10.1115/1.4062921","url":null,"abstract":"\u0000 A comprehensive computational study for the assessment of a horizontal solar calciner is presented. The heat and mass transfer models that have been developed give valuable insight and enlighten the fundamental principles that rule the solar-aided CaCO3 decomposition. The obtained computational data are appropriately interpreted and serve as guidelines in order to establish the operational framework of the solar reactor. Additionally, this set of predictive models identifies the optimum values of the key parameters that boost the performance of the process. The models have been validated comparing the computational results with the experimental data and the calciner performance is evaluated considering the overall process efficiency.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"13 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87815880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flat Heat Pipes (FHP) are commonly used as passive cooling system in portable electronic gadgets due to their compact profile. The present study investigates the effect of different working fluids on the thermal performance of a miniature flat heat pipe (FHP) under different orientations and condenser cooling mechanisms. Deionized (DI) water, acetone, ethanol, and methanol are chosen as working fluids in the FHP. Five different inclinations (0° (Horizontal), 30°, 45°, 60° and 90° (Vertical)) and two different condenser cooling methods (natural convection and forced convection with fan cooling) are considered in this experimental study. The FHP thermal performance is quantified in terms of overall temperature difference, thermal resistance, and effective thermal conductivity. The results indicate that comparatively higher effective thermal conductivity values are obtained for methanol and acetone heat pipes at low heat loads and under natural convection. At higher heat loads, the ethanol heat pipe had higher effective thermal conductivity values for the same condenser cooling method. For the case of forced convection cooling mode, the methanol heat pipe had enhanced thermal performance as compared to the other three fluids for all heat load ranges and different inclinations. Due to the higher boiling point of water, as a working fluid water is not suitable in most of the experimental trials except at high heat load under forced convection cooling and in a horizontal orientation.
{"title":"Effect of Working Fluid, Orientation and Cooling Mode on Thermal Performance of Miniature Flat Heat Pipe","authors":"J. Rathod, V. Lakhera, A. Shukla","doi":"10.1115/1.4062920","DOIUrl":"https://doi.org/10.1115/1.4062920","url":null,"abstract":"\u0000 Flat Heat Pipes (FHP) are commonly used as passive cooling system in portable electronic gadgets due to their compact profile. The present study investigates the effect of different working fluids on the thermal performance of a miniature flat heat pipe (FHP) under different orientations and condenser cooling mechanisms. Deionized (DI) water, acetone, ethanol, and methanol are chosen as working fluids in the FHP. Five different inclinations (0° (Horizontal), 30°, 45°, 60° and 90° (Vertical)) and two different condenser cooling methods (natural convection and forced convection with fan cooling) are considered in this experimental study. The FHP thermal performance is quantified in terms of overall temperature difference, thermal resistance, and effective thermal conductivity. The results indicate that comparatively higher effective thermal conductivity values are obtained for methanol and acetone heat pipes at low heat loads and under natural convection. At higher heat loads, the ethanol heat pipe had higher effective thermal conductivity values for the same condenser cooling method. For the case of forced convection cooling mode, the methanol heat pipe had enhanced thermal performance as compared to the other three fluids for all heat load ranges and different inclinations. Due to the higher boiling point of water, as a working fluid water is not suitable in most of the experimental trials except at high heat load under forced convection cooling and in a horizontal orientation.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"55 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83769895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Achraf Nedjar, A. Chaker, R. Absi, Yousra Lahmer, R. Bennacer
This work presents a numerical study on the performance of a stand-alone adsorption cooling system based on the silica gel/water couple driven by hybrid photovoltaic/thermal (PVT) collectors. This system is intended for the conservation of perishable agricultural products which require air-conditioned premises to preserve them. The weather conditions are those of North Africa (Algiers). Considering above, this paper aims at analyzing the PVT-Adsorption system with energy storage to guarantee a stabilized production and increase the solar coverage. TRNSYS was used to simulate the system taking into account hourly series of irradiation and ambient temperature covering one year. The performance study reveals that the DualSun PVT hybrid collectors used provide optimal annual production and that the adsorption cooling system offers more reliable production during summer. The temperature difference between the inside and outside of the cooled enclosure balances supply and demand. The loss analysis of the storage device indicates that losses depend, on the one hand, on the interior / exterior temperature difference of the storage tank with more significant values during the summer season. On the other hand, the losses also depend on the volume of the storage tank which was optimized in order to limit the heat exchange with the surroundings.
{"title":"Performance study of PVT system for cold production by adsorption in a Mediterranean climate: Foodstuffs preservation","authors":"Achraf Nedjar, A. Chaker, R. Absi, Yousra Lahmer, R. Bennacer","doi":"10.1115/1.4062866","DOIUrl":"https://doi.org/10.1115/1.4062866","url":null,"abstract":"\u0000 This work presents a numerical study on the performance of a stand-alone adsorption cooling system based on the silica gel/water couple driven by hybrid photovoltaic/thermal (PVT) collectors. This system is intended for the conservation of perishable agricultural products which require air-conditioned premises to preserve them. The weather conditions are those of North Africa (Algiers). Considering above, this paper aims at analyzing the PVT-Adsorption system with energy storage to guarantee a stabilized production and increase the solar coverage. TRNSYS was used to simulate the system taking into account hourly series of irradiation and ambient temperature covering one year. The performance study reveals that the DualSun PVT hybrid collectors used provide optimal annual production and that the adsorption cooling system offers more reliable production during summer. The temperature difference between the inside and outside of the cooled enclosure balances supply and demand. The loss analysis of the storage device indicates that losses depend, on the one hand, on the interior / exterior temperature difference of the storage tank with more significant values during the summer season. On the other hand, the losses also depend on the volume of the storage tank which was optimized in order to limit the heat exchange with the surroundings.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"85 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84960735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Che, H. Han, Xianlin Wu, Lei Huang, Hongyang Zheng
The Body-mounted fluid tube radiator (BMFTR) is a highly efficient heat rejection device for spacecraft. However, the heat rejection rate of the BMFTR is negatively impacted by the presence of solar panels mounted on the exterior of the spacecraft. In this study, a heat transfer model for the BMFTR was developed, and a simulation method was created to investigate the effect of solar panels on the radiator's performance. The accuracy of both the heat transfer model and simulation method was verified using on-orbit data from the China Tianhe module. It was found that external heat is absorbed by the solar panels, which in turn reduces the performance of the radiator. Furthermore, the decrease in the heat rejection rate was quantitatively evaluated, and it was found to be closely related to the spacecraft's attitude and the view factor between the solar panel and the radiator. The findings of this study on the impact of solar panels on the BMFTR's performance are meaningful for future research on spacecraft radiators and on-orbit operations.
{"title":"Effect of solar panel on performance of spacecraft body-mounted fluid tube radiator","authors":"B. Che, H. Han, Xianlin Wu, Lei Huang, Hongyang Zheng","doi":"10.1115/1.4062867","DOIUrl":"https://doi.org/10.1115/1.4062867","url":null,"abstract":"\u0000 The Body-mounted fluid tube radiator (BMFTR) is a highly efficient heat rejection device for spacecraft. However, the heat rejection rate of the BMFTR is negatively impacted by the presence of solar panels mounted on the exterior of the spacecraft. In this study, a heat transfer model for the BMFTR was developed, and a simulation method was created to investigate the effect of solar panels on the radiator's performance. The accuracy of both the heat transfer model and simulation method was verified using on-orbit data from the China Tianhe module. It was found that external heat is absorbed by the solar panels, which in turn reduces the performance of the radiator. Furthermore, the decrease in the heat rejection rate was quantitatively evaluated, and it was found to be closely related to the spacecraft's attitude and the view factor between the solar panel and the radiator. The findings of this study on the impact of solar panels on the BMFTR's performance are meaningful for future research on spacecraft radiators and on-orbit operations.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"107 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76844863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present work provides a reliable computational framework to investigate the laminar and turbulent forced convection of sodium and sodium-potassium (Na, NaK) in miniature heat sinks with hydraulic diameters between 1 and 5 mm. Na and NaK flow and heat transfer are studied numerically for a wide range of Reynolds numbers from 600 to 9,000 in three sharp-cornered miniature heat sinks with rectangular, pentagonal, and hexagonal cross-sections. For a fixed surface area to volume ratio in all three heat sinks and for both Na and NaK, it is observed that the rectangular minichannel heat sink provides the highest heat transfer rates. The rectangular miniature heat sink is shown to have a 280% higher convective heat transfer rate in comparison with the pentagonal heat sink. Moreover, the obtained convective heat transfer coefficients for NaK are almost 20% higher than the ones for Na in the investigated pentagonal heat sink in both laminar and turbulent flow regimes. At the same flow Peclet number in the studied rectangular and hexagonal heat sinks, both Na and NaK provide nearly identical average Nusselt numbers while NaK shows higher local and average Nusselt numbers compared to Na at the same Reynolds number.
{"title":"Computational framework development for heat transfer studies in liquid metal-cooled small-scale heat sinks with non-circular cross-sections","authors":"M. Pourghasemi, N. Fathi","doi":"10.1115/1.4062833","DOIUrl":"https://doi.org/10.1115/1.4062833","url":null,"abstract":"\u0000 The present work provides a reliable computational framework to investigate the laminar and turbulent forced convection of sodium and sodium-potassium (Na, NaK) in miniature heat sinks with hydraulic diameters between 1 and 5 mm. Na and NaK flow and heat transfer are studied numerically for a wide range of Reynolds numbers from 600 to 9,000 in three sharp-cornered miniature heat sinks with rectangular, pentagonal, and hexagonal cross-sections. For a fixed surface area to volume ratio in all three heat sinks and for both Na and NaK, it is observed that the rectangular minichannel heat sink provides the highest heat transfer rates. The rectangular miniature heat sink is shown to have a 280% higher convective heat transfer rate in comparison with the pentagonal heat sink. Moreover, the obtained convective heat transfer coefficients for NaK are almost 20% higher than the ones for Na in the investigated pentagonal heat sink in both laminar and turbulent flow regimes. At the same flow Peclet number in the studied rectangular and hexagonal heat sinks, both Na and NaK provide nearly identical average Nusselt numbers while NaK shows higher local and average Nusselt numbers compared to Na at the same Reynolds number.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"77 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85472557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kevin J. DeMarco, M. Polanka, Brian T. Bohan, J. L. Rutledge
The ultra-compact combustor (UCC) aims to decrease the length of gas turbine combustors using a unique design geometry which wraps a combustion chamber around the central axial flow. This distinctive design enables an out of the box type of cooling scheme to be investigated for the turbine inlet vanes, termed the hybrid guide vane (HGV) in the UCC. The leading edge of the HGV experiences only compressor exit air as combustion products do not interact with the vane upstream of the 14% axial chord location. Previous studies were conducted which computationally evaluated the viability of taking in freestream flow through the HGV stagnation region for use as coolant. Based on these studies, a six vane HGV was manufactured which incorporated a solid vane and five hollow vanes. Each of these vanes incorporated different features to vary the size of the internal plug, trailing edge exit, and film cooling holes. In the present study, the cooled HGV was experimentally analyzed using pressure, thermocouple, and infrared (IR) thermography measurements to evaluate internal coolant flowrates and pressure loss along with cooling performance. Furthermore, the vanes were compared to isolate the impact of design differences on vane cooling. It was found that the location of the internal plug and incorporation of film cooling holes had a minor impact on coolant flow and cooling. Additionally, results showed exit area had the largest impact on surface temperature and coolant mass flow where the largest exit area allowed less restricted coolant flow resulting in the lowest average surface temperature. However, completely blocking the exit slot forced coolant to exit only through film cooling holes, stagnating the majority of the internal flow, resulting in surface temperatures higher than the uncooled, solid vane.
{"title":"Design Impacts on Ram Air Vane Cooling in an Ultra-Compact Combustor","authors":"Kevin J. DeMarco, M. Polanka, Brian T. Bohan, J. L. Rutledge","doi":"10.1115/1.4062703","DOIUrl":"https://doi.org/10.1115/1.4062703","url":null,"abstract":"\u0000 The ultra-compact combustor (UCC) aims to decrease the length of gas turbine combustors using a unique design geometry which wraps a combustion chamber around the central axial flow. This distinctive design enables an out of the box type of cooling scheme to be investigated for the turbine inlet vanes, termed the hybrid guide vane (HGV) in the UCC. The leading edge of the HGV experiences only compressor exit air as combustion products do not interact with the vane upstream of the 14% axial chord location. Previous studies were conducted which computationally evaluated the viability of taking in freestream flow through the HGV stagnation region for use as coolant. Based on these studies, a six vane HGV was manufactured which incorporated a solid vane and five hollow vanes. Each of these vanes incorporated different features to vary the size of the internal plug, trailing edge exit, and film cooling holes. In the present study, the cooled HGV was experimentally analyzed using pressure, thermocouple, and infrared (IR) thermography measurements to evaluate internal coolant flowrates and pressure loss along with cooling performance. Furthermore, the vanes were compared to isolate the impact of design differences on vane cooling. It was found that the location of the internal plug and incorporation of film cooling holes had a minor impact on coolant flow and cooling. Additionally, results showed exit area had the largest impact on surface temperature and coolant mass flow where the largest exit area allowed less restricted coolant flow resulting in the lowest average surface temperature. However, completely blocking the exit slot forced coolant to exit only through film cooling holes, stagnating the majority of the internal flow, resulting in surface temperatures higher than the uncooled, solid vane.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"34 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76926103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The trend of miniaturization and intgration of the electronic device has put forward higher requirements on efficiency of heat radiating, which can hardly be satisfied by the traditional forced convection heat dissipation method. In this paper, the strategy of topology optimization technique is adopted to greatly improve the heat dissipation efficiency of a semiconductor ignition device. The penalization method is used to implement the topology optimization process. Three kinds of objective functions of thermal compliance, temperature variance and geometric average temperature were separately applied in the topological optimization of two typical uniform heat generation cases, and the resulted topologically optimization results were analyzed and compared. Based on the two benchmark cases, the appropriate objective function was selected to conduct structural optimization of semiconductor bridge ignition devices with the aim of making the highest temperature in the design domain the lowest possible. Additionally, a parametric study on the effect of thermal conductivity on topology optimization results was conducted, which leads to a design suggestion beneficial for heat dissipation and material selection.
{"title":"Topology Optimization Design for Heat Dissipation Performance of Semiconductor Ignition Device","authors":"Jia Chen, Xiaobing Zhang, Ruijie Zhu","doi":"10.1115/1.4062733","DOIUrl":"https://doi.org/10.1115/1.4062733","url":null,"abstract":"\u0000 The trend of miniaturization and intgration of the electronic device has put forward higher requirements on efficiency of heat radiating, which can hardly be satisfied by the traditional forced convection heat dissipation method. In this paper, the strategy of topology optimization technique is adopted to greatly improve the heat dissipation efficiency of a semiconductor ignition device. The penalization method is used to implement the topology optimization process. Three kinds of objective functions of thermal compliance, temperature variance and geometric average temperature were separately applied in the topological optimization of two typical uniform heat generation cases, and the resulted topologically optimization results were analyzed and compared. Based on the two benchmark cases, the appropriate objective function was selected to conduct structural optimization of semiconductor bridge ignition devices with the aim of making the highest temperature in the design domain the lowest possible. Additionally, a parametric study on the effect of thermal conductivity on topology optimization results was conducted, which leads to a design suggestion beneficial for heat dissipation and material selection.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"35 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89389780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The research work is carried out for deflagration and detonation combustion processes at different equivalence ratios of hydrogen–air mixtures in a pulse detonation combustor (PDC). Furthermore, the U-shape channel curvature radius and thickness effect on detonation wave propagation are also investigated. This numerical simulation has been done using a SIMPLE algorithm with the finite volume discretization method and laminar finite rate chemistry for volumetric reaction in the Ansys Fluent platform. The numerical result shows that the U-bend radius of R = 3.5 cm can enhance the faster deflagration-to-detonation transition. So far, the fully developed detonation wave was found near the curvature area of the detonation tube having a width of W = 8 cm. This enhanced detonation wave velocity reaches 2775 m/s, which is higher than the C-J detonation velocity. Furthermore, the entropy generation has been analyzed in two modes of the combustion process. The entropy generation number of 0.76 and 0.7 is obtained from the deflagration and detonation combustion processes. However, the entropy production rate is less in the detonation combustion process, but thermal entropy generation is more in the deflagration combustion process with a magnitude of 3.5 kJ/kg K for an equivalence ratio of φ = 1.5. A combustion efficiency of 78% is found in the detonation combustion process, which is comparatively higher than the deflagration process.
{"title":"Numerical Analysis on Detonation Wave and Combustion Efficiency of Pulse Detonation Combustor With U-Shape Combustor","authors":"Pinku Debnath, K. Pandey","doi":"10.1115/1.4062702","DOIUrl":"https://doi.org/10.1115/1.4062702","url":null,"abstract":"\u0000 The research work is carried out for deflagration and detonation combustion processes at different equivalence ratios of hydrogen–air mixtures in a pulse detonation combustor (PDC). Furthermore, the U-shape channel curvature radius and thickness effect on detonation wave propagation are also investigated. This numerical simulation has been done using a SIMPLE algorithm with the finite volume discretization method and laminar finite rate chemistry for volumetric reaction in the Ansys Fluent platform. The numerical result shows that the U-bend radius of R = 3.5 cm can enhance the faster deflagration-to-detonation transition. So far, the fully developed detonation wave was found near the curvature area of the detonation tube having a width of W = 8 cm. This enhanced detonation wave velocity reaches 2775 m/s, which is higher than the C-J detonation velocity. Furthermore, the entropy generation has been analyzed in two modes of the combustion process. The entropy generation number of 0.76 and 0.7 is obtained from the deflagration and detonation combustion processes. However, the entropy production rate is less in the detonation combustion process, but thermal entropy generation is more in the deflagration combustion process with a magnitude of 3.5 kJ/kg K for an equivalence ratio of φ = 1.5. A combustion efficiency of 78% is found in the detonation combustion process, which is comparatively higher than the deflagration process.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"11 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87104681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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