Pub Date : 2024-05-14DOI: 10.1177/09576509241254415
Shizhuo Peng, Chenheng Yuan, Jiang Lu
Enhanced methods of energy conversion present a viable solution for addressing energy load challenges. This study introduces a vibrating combustion engine designed to enhance energy conversion efficiency by harnessing flexible dynamics and variable asymmetric motion. However, the consideration of its unique dynamic effects has emerged as a pivotal challenge in fuel-air mixing and combustion research. This study introduces a fuel spray and mixing simulation method that facilitates the reciprocal exchange of coupling parameters between the combustion and dynamics models. It iterates the simulation outcomes of motion and combustion to predict mixture formation. Subsequently, the method is employed to explore the impact of injection position on fuel spray and mixture formation. Results show that there is an optimum injection position for the operation frequency, and retarding or advancing leads to slow compression and weak gas motion for fuel spray and mixing, although retarded injection provides high in-cylinder gas pressure and temperature. The early injection generally causes long penetration, small droplet diameter, slight impingement, and fast evaporation, unless it is too early. The results further indicate that when IAP = 6 mm, a more uniform mixture can be attained at the beginning of combustion, leading to a thermal efficiency of up to 42.9% for the engine.
{"title":"Dynamic coupling effects of injection on spray and mixture formation in an asymmetrically vibrating combustion engine","authors":"Shizhuo Peng, Chenheng Yuan, Jiang Lu","doi":"10.1177/09576509241254415","DOIUrl":"https://doi.org/10.1177/09576509241254415","url":null,"abstract":"Enhanced methods of energy conversion present a viable solution for addressing energy load challenges. This study introduces a vibrating combustion engine designed to enhance energy conversion efficiency by harnessing flexible dynamics and variable asymmetric motion. However, the consideration of its unique dynamic effects has emerged as a pivotal challenge in fuel-air mixing and combustion research. This study introduces a fuel spray and mixing simulation method that facilitates the reciprocal exchange of coupling parameters between the combustion and dynamics models. It iterates the simulation outcomes of motion and combustion to predict mixture formation. Subsequently, the method is employed to explore the impact of injection position on fuel spray and mixture formation. Results show that there is an optimum injection position for the operation frequency, and retarding or advancing leads to slow compression and weak gas motion for fuel spray and mixing, although retarded injection provides high in-cylinder gas pressure and temperature. The early injection generally causes long penetration, small droplet diameter, slight impingement, and fast evaporation, unless it is too early. The results further indicate that when IAP = 6 mm, a more uniform mixture can be attained at the beginning of combustion, leading to a thermal efficiency of up to 42.9% for the engine.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"45 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140980962","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}
Pub Date : 2024-02-07DOI: 10.1177/09576509241231852
M. Lança, João Gomes, Diogo Cabral, S. Hosouli
One of the problems in using PV cells to extract energy from sunlight is the temperature effect on PV cells. As the solar panel is heated, the conversion efficiency of light to electrical energy is diminished. Moreover, successive temperature elevations can cause dilatations in the array of cells which may also contribute to the degradation of the receiver. Some of the operating temperature mitigation approaches may include air-flow ventilation. In this study, data obtained by experimental and numerical simulations of a collector with bifacial PV cells is compared to the expressions found in the literature for the estimation of the heat transfer coefficient. Forced ventilation was applied to the studied collector as it accounts for much better heat dissipation. A new correlation for the estimation of the heat transfer coefficient is developed for such a geometry, for inlet velocities ranging between 3 and 8 m/s. Values of heat transfer coefficient estimated in the present work have been compared with studies of other researchers.
{"title":"Thermal performance of three concentrating collectors with bifacial PV cells. Part II – parametrical study","authors":"M. Lança, João Gomes, Diogo Cabral, S. Hosouli","doi":"10.1177/09576509241231852","DOIUrl":"https://doi.org/10.1177/09576509241231852","url":null,"abstract":"One of the problems in using PV cells to extract energy from sunlight is the temperature effect on PV cells. As the solar panel is heated, the conversion efficiency of light to electrical energy is diminished. Moreover, successive temperature elevations can cause dilatations in the array of cells which may also contribute to the degradation of the receiver. Some of the operating temperature mitigation approaches may include air-flow ventilation. In this study, data obtained by experimental and numerical simulations of a collector with bifacial PV cells is compared to the expressions found in the literature for the estimation of the heat transfer coefficient. Forced ventilation was applied to the studied collector as it accounts for much better heat dissipation. A new correlation for the estimation of the heat transfer coefficient is developed for such a geometry, for inlet velocities ranging between 3 and 8 m/s. Values of heat transfer coefficient estimated in the present work have been compared with studies of other researchers.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"99 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139794766","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}
Pub Date : 2024-02-07DOI: 10.1177/09576509241231852
M. Lança, João Gomes, Diogo Cabral, S. Hosouli
One of the problems in using PV cells to extract energy from sunlight is the temperature effect on PV cells. As the solar panel is heated, the conversion efficiency of light to electrical energy is diminished. Moreover, successive temperature elevations can cause dilatations in the array of cells which may also contribute to the degradation of the receiver. Some of the operating temperature mitigation approaches may include air-flow ventilation. In this study, data obtained by experimental and numerical simulations of a collector with bifacial PV cells is compared to the expressions found in the literature for the estimation of the heat transfer coefficient. Forced ventilation was applied to the studied collector as it accounts for much better heat dissipation. A new correlation for the estimation of the heat transfer coefficient is developed for such a geometry, for inlet velocities ranging between 3 and 8 m/s. Values of heat transfer coefficient estimated in the present work have been compared with studies of other researchers.
{"title":"Thermal performance of three concentrating collectors with bifacial PV cells. Part II – parametrical study","authors":"M. Lança, João Gomes, Diogo Cabral, S. Hosouli","doi":"10.1177/09576509241231852","DOIUrl":"https://doi.org/10.1177/09576509241231852","url":null,"abstract":"One of the problems in using PV cells to extract energy from sunlight is the temperature effect on PV cells. As the solar panel is heated, the conversion efficiency of light to electrical energy is diminished. Moreover, successive temperature elevations can cause dilatations in the array of cells which may also contribute to the degradation of the receiver. Some of the operating temperature mitigation approaches may include air-flow ventilation. In this study, data obtained by experimental and numerical simulations of a collector with bifacial PV cells is compared to the expressions found in the literature for the estimation of the heat transfer coefficient. Forced ventilation was applied to the studied collector as it accounts for much better heat dissipation. A new correlation for the estimation of the heat transfer coefficient is developed for such a geometry, for inlet velocities ranging between 3 and 8 m/s. Values of heat transfer coefficient estimated in the present work have been compared with studies of other researchers.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"52 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139854595","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}
Pub Date : 2024-02-06DOI: 10.1177/09576509241232037
Joonhyung Kim, Munseong Kwon, Jaewoo Park, Sunghyuk Park, Woong Hwang
Rotary compressors applied to heating and cooling cycles accounts for a large proportion of the total energy consumed in the system. Therefore, improving compressor efficiency is crucial in order to reduce energy consumption. Design review and improvement efforts have primarily focused on compression and discharge parts with high pressure. However, due to the limitations in design improvements for the compression and discharge parts, enhancements for other components are necessary to further increase compressor efficiency. In this study, the design of the suction part of the rotary compressor was modified using FSI (Fluid-Structure Interact) analysis scheme. In order to improve the design of the suction shape, new suction shape types were devised as alternatives to the existing through type. Both the newly devised C-type and E-type suction shapes presented an increase in cooling capacity due to reduced suction resistance, with the E-type demonstrating greater improvement compared to the C-type. Consequently, a verification of the effect based on the detailed design dimensions was further conducted for the E-type suction shape. The final selected improved model increased the suction flow rate by approximately 2.5% compared to the base model. This indicates that significant improvement for the compressor efficiency can be achieved through modifying designs in parts other than the compression and discharge sections. In addition, a design improvement process was established to analyze internal flow using FSI analysis.
用于加热和冷却循环的旋转式压缩机在系统总能耗中占很大比例。因此，提高压缩机的效率对于降低能耗至关重要。设计审查和改进工作主要集中在高压的压缩和排放部件上。然而，由于压缩和排放部件的设计改进存在局限性，因此有必要对其他部件进行改进，以进一步提高压缩机的效率。在本研究中，使用 FSI（流体-结构相互作用）分析方案对旋转式压缩机吸气部分的设计进行了改进。为了改进吸气形状的设计，设计了新的吸气形状类型来替代现有的直通型。新设计的 C 型和 E 型吸气形状都由于减少了吸气阻力而提高了冷却能力，其中 E 型吸气形状比 C 型吸气形状有更大的改进。因此，根据详细的设计尺寸，对 E 型吸气形状的效果进行了进一步验证。最终选定的改进型比基本型的吸气流量提高了约 2.5%。这表明，通过修改压缩和排气部分以外的其他部分的设计，可以显著提高压缩机的效率。此外，还建立了一个设计改进流程，利用 FSI 分析法对内部流动进行分析。
{"title":"Design improvement for suction shape in rotary compressor","authors":"Joonhyung Kim, Munseong Kwon, Jaewoo Park, Sunghyuk Park, Woong Hwang","doi":"10.1177/09576509241232037","DOIUrl":"https://doi.org/10.1177/09576509241232037","url":null,"abstract":"Rotary compressors applied to heating and cooling cycles accounts for a large proportion of the total energy consumed in the system. Therefore, improving compressor efficiency is crucial in order to reduce energy consumption. Design review and improvement efforts have primarily focused on compression and discharge parts with high pressure. However, due to the limitations in design improvements for the compression and discharge parts, enhancements for other components are necessary to further increase compressor efficiency. In this study, the design of the suction part of the rotary compressor was modified using FSI (Fluid-Structure Interact) analysis scheme. In order to improve the design of the suction shape, new suction shape types were devised as alternatives to the existing through type. Both the newly devised C-type and E-type suction shapes presented an increase in cooling capacity due to reduced suction resistance, with the E-type demonstrating greater improvement compared to the C-type. Consequently, a verification of the effect based on the detailed design dimensions was further conducted for the E-type suction shape. The final selected improved model increased the suction flow rate by approximately 2.5% compared to the base model. This indicates that significant improvement for the compressor efficiency can be achieved through modifying designs in parts other than the compression and discharge sections. In addition, a design improvement process was established to analyze internal flow using FSI analysis.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"141 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139859666","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}
Pub Date : 2024-02-06DOI: 10.1177/09576509241232037
Joonhyung Kim, Munseong Kwon, Jaewoo Park, Sunghyuk Park, Woong Hwang
Rotary compressors applied to heating and cooling cycles accounts for a large proportion of the total energy consumed in the system. Therefore, improving compressor efficiency is crucial in order to reduce energy consumption. Design review and improvement efforts have primarily focused on compression and discharge parts with high pressure. However, due to the limitations in design improvements for the compression and discharge parts, enhancements for other components are necessary to further increase compressor efficiency. In this study, the design of the suction part of the rotary compressor was modified using FSI (Fluid-Structure Interact) analysis scheme. In order to improve the design of the suction shape, new suction shape types were devised as alternatives to the existing through type. Both the newly devised C-type and E-type suction shapes presented an increase in cooling capacity due to reduced suction resistance, with the E-type demonstrating greater improvement compared to the C-type. Consequently, a verification of the effect based on the detailed design dimensions was further conducted for the E-type suction shape. The final selected improved model increased the suction flow rate by approximately 2.5% compared to the base model. This indicates that significant improvement for the compressor efficiency can be achieved through modifying designs in parts other than the compression and discharge sections. In addition, a design improvement process was established to analyze internal flow using FSI analysis.
用于加热和冷却循环的旋转式压缩机在系统总能耗中占很大比例。因此，提高压缩机的效率对于降低能耗至关重要。设计审查和改进工作主要集中在高压的压缩和排放部件上。然而，由于压缩和排放部件的设计改进存在局限性，因此有必要对其他部件进行改进，以进一步提高压缩机的效率。在本研究中，使用 FSI（流体-结构相互作用）分析方案对旋转式压缩机吸气部分的设计进行了改进。为了改进吸气形状的设计，设计了新的吸气形状类型来替代现有的直通型。新设计的 C 型和 E 型吸气形状都由于减少了吸气阻力而提高了冷却能力，其中 E 型吸气形状比 C 型吸气形状有更大的改进。因此，根据详细的设计尺寸，对 E 型吸气形状的效果进行了进一步验证。最终选定的改进型比基本型的吸气流量提高了约 2.5%。这表明，通过修改压缩和排气部分以外的其他部分的设计，可以显著提高压缩机的效率。此外，还建立了一个设计改进流程，利用 FSI 分析法对内部流动进行分析。
{"title":"Design improvement for suction shape in rotary compressor","authors":"Joonhyung Kim, Munseong Kwon, Jaewoo Park, Sunghyuk Park, Woong Hwang","doi":"10.1177/09576509241232037","DOIUrl":"https://doi.org/10.1177/09576509241232037","url":null,"abstract":"Rotary compressors applied to heating and cooling cycles accounts for a large proportion of the total energy consumed in the system. Therefore, improving compressor efficiency is crucial in order to reduce energy consumption. Design review and improvement efforts have primarily focused on compression and discharge parts with high pressure. However, due to the limitations in design improvements for the compression and discharge parts, enhancements for other components are necessary to further increase compressor efficiency. In this study, the design of the suction part of the rotary compressor was modified using FSI (Fluid-Structure Interact) analysis scheme. In order to improve the design of the suction shape, new suction shape types were devised as alternatives to the existing through type. Both the newly devised C-type and E-type suction shapes presented an increase in cooling capacity due to reduced suction resistance, with the E-type demonstrating greater improvement compared to the C-type. Consequently, a verification of the effect based on the detailed design dimensions was further conducted for the E-type suction shape. The final selected improved model increased the suction flow rate by approximately 2.5% compared to the base model. This indicates that significant improvement for the compressor efficiency can be achieved through modifying designs in parts other than the compression and discharge sections. In addition, a design improvement process was established to analyze internal flow using FSI analysis.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"221 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139799672","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}
Pub Date : 2024-02-05DOI: 10.1177/09576509241231023
Haohao Wang, Limin Gao, Guang Yang, Baohai Wu
The probability-based uncertainty quantification (UQ) methods require a large amount of sampled data to construct the probability distribution of uncertain input parameters. However, it is a common situation that only limited and scarce sampled data are available in engineering applications due to expensive tests. In the present paper, the Data-Driven Polynomial Chaos (DDPC) method is adopted, which can propagate input uncertainty in the case of scarce sampled data. The calculation accuracy and convergence of the self-developed DDPC method are validated by a nonlinear test function. Subsequently, the DDPC method is applied to investigate the uncertain impact of stagger angle errors on the aerodynamic performance of a subsonic compressor cascade. A family of manufacturing error data of stagger angles was obtained from the real compressor blades. Based on the limited measurement data, the DDPC method combined with Computational Fluid Dynamics (CFD) simulation is employed to quantify the performance impact of the compressor cascade. The results show that the performance dispersion under off-design conditions is more prominent than that under design conditions. The actual aerodynamic performance deviating from the nominal performance is not a small probability event, and the probability of deviating from the nominal loss coefficient and exit flow angle by more than 1% can reach up to 47.6% and 36.8% under high incidence i = 7°. Detailed analysis shows that stagger angle errors have a significant effect on the flow state near the leading edge, resulting in variations in separation bubble size and boundary layer thickness.
{"title":"A data-driven polynomial chaos method for uncertainty quantification of a subsonic compressor cascade with stagger angle errors","authors":"Haohao Wang, Limin Gao, Guang Yang, Baohai Wu","doi":"10.1177/09576509241231023","DOIUrl":"https://doi.org/10.1177/09576509241231023","url":null,"abstract":"The probability-based uncertainty quantification (UQ) methods require a large amount of sampled data to construct the probability distribution of uncertain input parameters. However, it is a common situation that only limited and scarce sampled data are available in engineering applications due to expensive tests. In the present paper, the Data-Driven Polynomial Chaos (DDPC) method is adopted, which can propagate input uncertainty in the case of scarce sampled data. The calculation accuracy and convergence of the self-developed DDPC method are validated by a nonlinear test function. Subsequently, the DDPC method is applied to investigate the uncertain impact of stagger angle errors on the aerodynamic performance of a subsonic compressor cascade. A family of manufacturing error data of stagger angles was obtained from the real compressor blades. Based on the limited measurement data, the DDPC method combined with Computational Fluid Dynamics (CFD) simulation is employed to quantify the performance impact of the compressor cascade. The results show that the performance dispersion under off-design conditions is more prominent than that under design conditions. The actual aerodynamic performance deviating from the nominal performance is not a small probability event, and the probability of deviating from the nominal loss coefficient and exit flow angle by more than 1% can reach up to 47.6% and 36.8% under high incidence i = 7°. Detailed analysis shows that stagger angle errors have a significant effect on the flow state near the leading edge, resulting in variations in separation bubble size and boundary layer thickness.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"21 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139805035","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}
Pub Date : 2024-02-05DOI: 10.1177/09576509241231023
Haohao Wang, Limin Gao, Guang Yang, Baohai Wu
The probability-based uncertainty quantification (UQ) methods require a large amount of sampled data to construct the probability distribution of uncertain input parameters. However, it is a common situation that only limited and scarce sampled data are available in engineering applications due to expensive tests. In the present paper, the Data-Driven Polynomial Chaos (DDPC) method is adopted, which can propagate input uncertainty in the case of scarce sampled data. The calculation accuracy and convergence of the self-developed DDPC method are validated by a nonlinear test function. Subsequently, the DDPC method is applied to investigate the uncertain impact of stagger angle errors on the aerodynamic performance of a subsonic compressor cascade. A family of manufacturing error data of stagger angles was obtained from the real compressor blades. Based on the limited measurement data, the DDPC method combined with Computational Fluid Dynamics (CFD) simulation is employed to quantify the performance impact of the compressor cascade. The results show that the performance dispersion under off-design conditions is more prominent than that under design conditions. The actual aerodynamic performance deviating from the nominal performance is not a small probability event, and the probability of deviating from the nominal loss coefficient and exit flow angle by more than 1% can reach up to 47.6% and 36.8% under high incidence i = 7°. Detailed analysis shows that stagger angle errors have a significant effect on the flow state near the leading edge, resulting in variations in separation bubble size and boundary layer thickness.
{"title":"A data-driven polynomial chaos method for uncertainty quantification of a subsonic compressor cascade with stagger angle errors","authors":"Haohao Wang, Limin Gao, Guang Yang, Baohai Wu","doi":"10.1177/09576509241231023","DOIUrl":"https://doi.org/10.1177/09576509241231023","url":null,"abstract":"The probability-based uncertainty quantification (UQ) methods require a large amount of sampled data to construct the probability distribution of uncertain input parameters. However, it is a common situation that only limited and scarce sampled data are available in engineering applications due to expensive tests. In the present paper, the Data-Driven Polynomial Chaos (DDPC) method is adopted, which can propagate input uncertainty in the case of scarce sampled data. The calculation accuracy and convergence of the self-developed DDPC method are validated by a nonlinear test function. Subsequently, the DDPC method is applied to investigate the uncertain impact of stagger angle errors on the aerodynamic performance of a subsonic compressor cascade. A family of manufacturing error data of stagger angles was obtained from the real compressor blades. Based on the limited measurement data, the DDPC method combined with Computational Fluid Dynamics (CFD) simulation is employed to quantify the performance impact of the compressor cascade. The results show that the performance dispersion under off-design conditions is more prominent than that under design conditions. The actual aerodynamic performance deviating from the nominal performance is not a small probability event, and the probability of deviating from the nominal loss coefficient and exit flow angle by more than 1% can reach up to 47.6% and 36.8% under high incidence i = 7°. Detailed analysis shows that stagger angle errors have a significant effect on the flow state near the leading edge, resulting in variations in separation bubble size and boundary layer thickness.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"58 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139864755","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 axial compressor in compressed air energy storage (CAES) system needs to operate stably and efficiently within a wide working range. The stator gap plays a critical role in suppressing corner separation and enhancing blade throughflow. The primary objective of this study is to determine the optimal combination of stator gaps to further expand the stable working range of the compressor while ensuring high efficiency. In this study, the flow characteristics of different stator gaps of the five-stage axial compressor in a specific CAES system are researched numerically. Firstly, the impact of different stator gaps on the aerodynamic performance is analyzed. The stator gap effectively broadens the stable working range of the compressor, with the hub gap exhibiting greater potential for expansion compared to the shroud gap. Subsequently, a comparative analysis is conducted on the internal flow of the third stage stator under near-stall conditions. Different gap leakage forms different vortex structures, and the gap leakage can effectively eliminate the accumulation of low-energy fluid in the corner area, optimize the limit streamlines on the blade suction surface and the temperature distribution. The low-velocity area caused by different stator gaps is also different. Finally, energy loss and energy dissipation with different stator gaps are explored. The gap leakage flow results in high energy loss, and different stator gaps exhibit notable differences in distribution of the high energy loss regions. Different types of stator gaps exhibit consistent high energy dissipation areas, which include the leading-edge stagnation area, boundary layer area on blade surface, and wake area. It is important to note that the high energy loss area does not necessarily coincide with the high energy dissipation area. The combined application of two loss evaluation methods contributes to a more comprehensive investigation of the loss distribution characteristics of the compressor.
{"title":"Characteristics of the axial compressor with different stator gaps in compressed air energy storage system","authors":"Pengfei Li, Zhitao Zuo, Xin Zhou, Jingxin Li, Wenbin Guo, Haisheng Chen","doi":"10.1177/09576509241227290","DOIUrl":"https://doi.org/10.1177/09576509241227290","url":null,"abstract":"The axial compressor in compressed air energy storage (CAES) system needs to operate stably and efficiently within a wide working range. The stator gap plays a critical role in suppressing corner separation and enhancing blade throughflow. The primary objective of this study is to determine the optimal combination of stator gaps to further expand the stable working range of the compressor while ensuring high efficiency. In this study, the flow characteristics of different stator gaps of the five-stage axial compressor in a specific CAES system are researched numerically. Firstly, the impact of different stator gaps on the aerodynamic performance is analyzed. The stator gap effectively broadens the stable working range of the compressor, with the hub gap exhibiting greater potential for expansion compared to the shroud gap. Subsequently, a comparative analysis is conducted on the internal flow of the third stage stator under near-stall conditions. Different gap leakage forms different vortex structures, and the gap leakage can effectively eliminate the accumulation of low-energy fluid in the corner area, optimize the limit streamlines on the blade suction surface and the temperature distribution. The low-velocity area caused by different stator gaps is also different. Finally, energy loss and energy dissipation with different stator gaps are explored. The gap leakage flow results in high energy loss, and different stator gaps exhibit notable differences in distribution of the high energy loss regions. Different types of stator gaps exhibit consistent high energy dissipation areas, which include the leading-edge stagnation area, boundary layer area on blade surface, and wake area. It is important to note that the high energy loss area does not necessarily coincide with the high energy dissipation area. The combined application of two loss evaluation methods contributes to a more comprehensive investigation of the loss distribution characteristics of the compressor.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"16 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139612469","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}
Pub Date : 2024-01-15DOI: 10.1177/09576509241227479
Yang Chen, Yujuan Zhao, Xiaodan Zhang, Yanhao Cao, Liangmou Li
In order to figure out the influence of water film on the performance of the turbomachinery, understand the mechanism of the interaction between the high-speed airflow and the water film in turbomachinery, and provide a reference for the design of the subsequent experiments and hollow stationary blade water removal by heating. The commercial software FLUENT with the Eulerian Wall Films model is used to establish a solution method for simulating the flow of water film on the blade. The accuracy of the solution method is verified by comparing it with the results of the water film thickness experiment on the surface of the plate. The distribution of the water film on the outer surface of the vane as well as the influence of the water film on the mainstream field are numerically studied in the condition of the wet steam mainstream. The results show that the gradient of water film thickness on the pressure surface is relatively gentle and is along the radial direction. The gradient of water film thickness on the suction side is along the axial direction, and the value is larger; There is a V-shaped water film agglomeration area on the suction surface near the trailing edge where the water film thickness is greater than 45.7 μm; The top areas on both the suction side and pressure side produce a local water film agglomeration area with the dual effect of the secondary flow and the centrifugal force of the mainstream; The water film flow on the blade surface has little influence of the steam velocity and the speed of the mainstream. The increase of local pressure on the surface leads to an increase in the pressure of the adjacent mainstream areas.
为了弄清水膜对透平机械性能的影响，了解透平机械中高速气流与水膜相互作用的机理，为后续实验设计和空心静止叶片加热除水提供参考。利用商业软件 FLUENT 的欧拉壁膜模型，建立了模拟叶片上水膜流动的求解方法。通过与叶片表面水膜厚度实验结果进行比较，验证了求解方法的准确性。在湿蒸汽主流条件下，对叶片外表面水膜的分布以及水膜对主流场的影响进行了数值研究。结果表明，压力面上的水膜厚度梯度相对平缓，且沿径向分布。吸气面上的水膜厚度梯度沿轴向，且数值较大；吸气面上靠近后缘处有一个水膜厚度大于 45.7 μm 的 V 形水膜聚集区；吸气面和受压面的顶部区域在二次流和主流离心力的双重作用下产生了局部水膜聚集区；叶片表面的水膜流对蒸汽速度和主流速度的影响较小。表面局部压力的增加会导致相邻主流区域压力的增加。
{"title":"Numerical study on the three-dimensional flow of water film on the outer surface of the hollow stationary blade","authors":"Yang Chen, Yujuan Zhao, Xiaodan Zhang, Yanhao Cao, Liangmou Li","doi":"10.1177/09576509241227479","DOIUrl":"https://doi.org/10.1177/09576509241227479","url":null,"abstract":"In order to figure out the influence of water film on the performance of the turbomachinery, understand the mechanism of the interaction between the high-speed airflow and the water film in turbomachinery, and provide a reference for the design of the subsequent experiments and hollow stationary blade water removal by heating. The commercial software FLUENT with the Eulerian Wall Films model is used to establish a solution method for simulating the flow of water film on the blade. The accuracy of the solution method is verified by comparing it with the results of the water film thickness experiment on the surface of the plate. The distribution of the water film on the outer surface of the vane as well as the influence of the water film on the mainstream field are numerically studied in the condition of the wet steam mainstream. The results show that the gradient of water film thickness on the pressure surface is relatively gentle and is along the radial direction. The gradient of water film thickness on the suction side is along the axial direction, and the value is larger; There is a V-shaped water film agglomeration area on the suction surface near the trailing edge where the water film thickness is greater than 45.7 μm; The top areas on both the suction side and pressure side produce a local water film agglomeration area with the dual effect of the secondary flow and the centrifugal force of the mainstream; The water film flow on the blade surface has little influence of the steam velocity and the speed of the mainstream. The increase of local pressure on the surface leads to an increase in the pressure of the adjacent mainstream areas.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":" 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139620299","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}
Pub Date : 2024-01-12DOI: 10.1177/09576509241227299
Y. Muralikrishna, Seerapu Siva Satyanarayana Reddy, M. Sahu, M. Mohan Jagadeesh Kumar
The present work aims at investigating, numerically, the heat transfer characteristics of transformer cooling system under forced circulation for three different winding configurations. The purpose of a transformer cooling system is to keep the hot spot temperature within the critical value for a long life of transformer, which increases with enhanced cooling of transformer windings. Thus, two different winding configurations are modeled by providing space within the windings (an intra-space model) and in between the windings (an inter-space model) to improve the fluid-solid interaction. A conventional winding, without spacing, is also modeled for comparative study. A 315 kVA, 3-phase core type transformer is taken as the base model from which the winding and core specifications are obtained analytically. Parameters chosen to measure the influence of winding configuration are local temperature distribution in the windings and core and maximum transformer temperature. Results are obtained for all three models with varying space for various cooling mediums like naphthenic oil, silicon oil, and synthetic ester oil at flow velocities ranging from 0.72 m/s to 2.16 m/s. It is observed that the gap between the windings, interspacing, decreases the secondary winding temperatures, while it increases the core and primary winding temperatures. However, the intra spacing configuration finds a drop in local temperatures at all locations of the transformer windings and core. The enhanced heat dissipation to the cooling agent, with intra spacing winding configuration, reduces the maximum transformer temperature. Contrasting to the above, the inter-space model has an adverse effect on maximum temperature at all widths of space considered. Quantitatively, the space within the transformer reduces the maximum temperature by 5% in comparison with the space between the windings. The increased velocity of the cooling medium, Naphthenic oil, from 0.72 m/s to 2.16 m/s reduces the maximum temperature by 4.5 units. The study made to know the role of cooling medium discloses that the synthetic ester oil shows better performance for reducing temperature values due to its highly viscous nature.
{"title":"A numerical study on effect of intra and inter spaced winding configuration on performance of oil forced transformer cooling system","authors":"Y. Muralikrishna, Seerapu Siva Satyanarayana Reddy, M. Sahu, M. Mohan Jagadeesh Kumar","doi":"10.1177/09576509241227299","DOIUrl":"https://doi.org/10.1177/09576509241227299","url":null,"abstract":"The present work aims at investigating, numerically, the heat transfer characteristics of transformer cooling system under forced circulation for three different winding configurations. The purpose of a transformer cooling system is to keep the hot spot temperature within the critical value for a long life of transformer, which increases with enhanced cooling of transformer windings. Thus, two different winding configurations are modeled by providing space within the windings (an intra-space model) and in between the windings (an inter-space model) to improve the fluid-solid interaction. A conventional winding, without spacing, is also modeled for comparative study. A 315 kVA, 3-phase core type transformer is taken as the base model from which the winding and core specifications are obtained analytically. Parameters chosen to measure the influence of winding configuration are local temperature distribution in the windings and core and maximum transformer temperature. Results are obtained for all three models with varying space for various cooling mediums like naphthenic oil, silicon oil, and synthetic ester oil at flow velocities ranging from 0.72 m/s to 2.16 m/s. It is observed that the gap between the windings, interspacing, decreases the secondary winding temperatures, while it increases the core and primary winding temperatures. However, the intra spacing configuration finds a drop in local temperatures at all locations of the transformer windings and core. The enhanced heat dissipation to the cooling agent, with intra spacing winding configuration, reduces the maximum transformer temperature. Contrasting to the above, the inter-space model has an adverse effect on maximum temperature at all widths of space considered. Quantitatively, the space within the transformer reduces the maximum temperature by 5% in comparison with the space between the windings. The increased velocity of the cooling medium, Naphthenic oil, from 0.72 m/s to 2.16 m/s reduces the maximum temperature by 4.5 units. The study made to know the role of cooling medium discloses that the synthetic ester oil shows better performance for reducing temperature values due to its highly viscous nature.","PeriodicalId":509769,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"51 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139531863","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：