Pub Date : 2024-04-29DOI: 10.1177/09576509241250128
Sergio M Moreno-Buesa, Emilio Muñoz-Cerón, Gustavo Nofuentes Garrido, Slawomir Gulkowski, Juan de la Casa Higueras, Jorge Aguilera Tejero
Bifacial solar technology has experienced exponential growth in recent years and its trend is increasing for the coming years. Considering the advantages that it offers over monofacial technology such as its current price equivalence, the increase in performance thanks to the production of the rear face and the consecutive reduction of the LCOE, it is logical that more and more photovoltaic plants with this technology are been installed. Nowadays, there are some regulatory gaps regarding bifacial technology and, due to this growing trend, it is necessary to study, research and implement the optimal way to evaluate these systems. This article has experimented with a 3.3 kW bifacial photovoltaic system, divided into two strings with different configurations, whose monitoring system has all the instrumentation included in the IEC 61,724 standard, with the addition that it has several rear irradiance sensors arranged in different locations of the system to evaluate the variability of this parameter. After an experimental campaign of 9 months, a power estimation analysis and the calculation of the PR and PR25°C have been carried out using the different rear irradiance sensors. The variability of this parameter depending on the location of the sensor has affected the results in such a way that the RMSE committed in the power estimation has varied between 10.22% and 2.63%, while the PR and PR25°C of the system has oscillated between 0.84 for the most unfavorable case and 0.95 in the most favorable case. Assumed the great variability between performance ratios, it is necessary to establish a specific normative standard for the evaluation of Bifacial PV systems.
{"title":"Characterization of bifacial technology Pv systems","authors":"Sergio M Moreno-Buesa, Emilio Muñoz-Cerón, Gustavo Nofuentes Garrido, Slawomir Gulkowski, Juan de la Casa Higueras, Jorge Aguilera Tejero","doi":"10.1177/09576509241250128","DOIUrl":"https://doi.org/10.1177/09576509241250128","url":null,"abstract":"Bifacial solar technology has experienced exponential growth in recent years and its trend is increasing for the coming years. Considering the advantages that it offers over monofacial technology such as its current price equivalence, the increase in performance thanks to the production of the rear face and the consecutive reduction of the LCOE, it is logical that more and more photovoltaic plants with this technology are been installed. Nowadays, there are some regulatory gaps regarding bifacial technology and, due to this growing trend, it is necessary to study, research and implement the optimal way to evaluate these systems. This article has experimented with a 3.3 kW bifacial photovoltaic system, divided into two strings with different configurations, whose monitoring system has all the instrumentation included in the IEC 61,724 standard, with the addition that it has several rear irradiance sensors arranged in different locations of the system to evaluate the variability of this parameter. After an experimental campaign of 9 months, a power estimation analysis and the calculation of the PR and PR<jats:sub>25°C</jats:sub> have been carried out using the different rear irradiance sensors. The variability of this parameter depending on the location of the sensor has affected the results in such a way that the RMSE committed in the power estimation has varied between 10.22% and 2.63%, while the PR and PR<jats:sub>25°C</jats:sub> of the system has oscillated between 0.84 for the most unfavorable case and 0.95 in the most favorable case. Assumed the great variability between performance ratios, it is necessary to establish a specific normative standard for the evaluation of Bifacial PV systems.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"21 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140837442","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}
Pub Date : 2024-04-20DOI: 10.1177/09576509241247601
Jinyuan Shi
A high-precision availability prediction, availability monitoring, and availability improvement method for in-service nuclear power plants has been proposed. The calculation formula for availability characteristic quantities and categories of planned maintenance for nuclear power plants are introduced. For nuclear power plants that have been in operation for less than 5 years, an availability prediction method based on statistical data is adopted to predict the equivalent availability factor of nuclear power plants. For nuclear power plants with operation years greater than or equal to 5 years, an availability prediction method based on power function and polynomial is adopted to predict the equivalent availability factor of nuclear power plants, and an accuracy verification method of availability prediction for nuclear power plants is provided. Based on availability prediction values and qualification criteria for availability monitoring, the availability monitoring of nuclear power plants is carried out. The optimization for numbers of planned maintenance days and newly added unplanned maintenance days based on different planned maintenance years promote the availability improvement of nuclear power plants. The relative error of availability prediction for an 1000 MW nuclear power plant and application example of optimized maintenance measures for different planned maintenance years are provided. The results show that the availability prediction method based on power function has high prediction accuracy and conforms to the availability trend of nuclear power plants. Based on the high-precision prediction results of availability, optimizing the number of planned maintenance days for different planned maintenance years can promote the availability improvement of in-service nuclear power plants.
{"title":"Availability monitoring and improvement method for in-service nuclear power plants based on high-precision prediction of availability","authors":"Jinyuan Shi","doi":"10.1177/09576509241247601","DOIUrl":"https://doi.org/10.1177/09576509241247601","url":null,"abstract":"A high-precision availability prediction, availability monitoring, and availability improvement method for in-service nuclear power plants has been proposed. The calculation formula for availability characteristic quantities and categories of planned maintenance for nuclear power plants are introduced. For nuclear power plants that have been in operation for less than 5 years, an availability prediction method based on statistical data is adopted to predict the equivalent availability factor of nuclear power plants. For nuclear power plants with operation years greater than or equal to 5 years, an availability prediction method based on power function and polynomial is adopted to predict the equivalent availability factor of nuclear power plants, and an accuracy verification method of availability prediction for nuclear power plants is provided. Based on availability prediction values and qualification criteria for availability monitoring, the availability monitoring of nuclear power plants is carried out. The optimization for numbers of planned maintenance days and newly added unplanned maintenance days based on different planned maintenance years promote the availability improvement of nuclear power plants. The relative error of availability prediction for an 1000 MW nuclear power plant and application example of optimized maintenance measures for different planned maintenance years are provided. The results show that the availability prediction method based on power function has high prediction accuracy and conforms to the availability trend of nuclear power plants. Based on the high-precision prediction results of availability, optimizing the number of planned maintenance days for different planned maintenance years can promote the availability improvement of in-service nuclear power plants.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"101 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140630721","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}
In this paper, the unsteady flow and pressure pulsation in 11-stage centrifugal pump were analyzed based on large eddy simulation. The performances from the numerical simulation agreed with the ones from the experiment. The numerical results show that large pressure gradient area appears on trailing edge of blade pressure surface, and large vorticity intensity area appears on blade suction surface and trailing edge. The vortexes in the impeller passage decrease obviously with the increase of flow rate from 0.4 Q to 1.2 Q. As the stage increase, there is a local high pressure area at the tongue and it affects the fluid backflow. The main frequency of the pulsation at the impeller inlet is the blade passing frequency ( fBPF), and the main frequency at the impeller outlet and the interface is 2 fBPF. Due to interstage interference, the main frequency of the second impeller includes blade passing frequency of the first stage impeller (5 fn) and its own blade passing frequency (7 fn). With the increase of the stages, the rule of pulsation gradually tends to be consistent.
{"title":"Analysis of unsteady flow and pressure pulsation of multistage centrifugal pump based on actual size","authors":"Baoling Cui, Yingbin Zhang, Yakun Huang, Zuchao Zhu","doi":"10.1177/09576509241248212","DOIUrl":"https://doi.org/10.1177/09576509241248212","url":null,"abstract":"In this paper, the unsteady flow and pressure pulsation in 11-stage centrifugal pump were analyzed based on large eddy simulation. The performances from the numerical simulation agreed with the ones from the experiment. The numerical results show that large pressure gradient area appears on trailing edge of blade pressure surface, and large vorticity intensity area appears on blade suction surface and trailing edge. The vortexes in the impeller passage decrease obviously with the increase of flow rate from 0.4 Q to 1.2 Q. As the stage increase, there is a local high pressure area at the tongue and it affects the fluid backflow. The main frequency of the pulsation at the impeller inlet is the blade passing frequency ( f<jats:sub>BPF</jats:sub>), and the main frequency at the impeller outlet and the interface is 2 f<jats:sub>BPF</jats:sub>. Due to interstage interference, the main frequency of the second impeller includes blade passing frequency of the first stage impeller (5 f<jats:sub>n</jats:sub>) and its own blade passing frequency (7 f<jats:sub>n</jats:sub>). With the increase of the stages, the rule of pulsation gradually tends to be consistent.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"7 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140626728","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}
Pub Date : 2024-04-17DOI: 10.1177/09576509241248213
Erol Kurt, Mustafa Demirci, Mustafa İlbaş
Heat transfer problem is explored for a new-designed low power generator. A self-cooling mechanism of the generator is designed and implemented for the forced convection via a fan being on the generator rotor. In addition, air is naturally directed towards the lateral parts of the machine in air gaps between stator and rotors. The designed fan has 16 blades with 65 degrees. The CFD and experimental self-cooling analyses are performed to focus on the flow velocities and temperature measurements. In this study, it has been aimed to compare heat transfers by the natural convection and by the forced convection. For this reason, besides Rayleigh ( Ra), Nusselt ( Nu), Grashof ( Gr) and Reynolds ( Re) numbers, heat transfer terms on the small winding coil, which is important heat source for the generator, are calculated for natural and forced convection. They are also clarified experimentally and theoretically. The heat transfer at 300 rpm varies between 0.04 W and 0.30 W by time for forced convection and varies between 0.21 W and 0.30 W by time for natural convection, whereas, it increases up at 1000 rpm from 0.50 W to 1.49 W by time for forced convection and from 0.02 W to 0.45 W by time for natural convection. It is proven that the proposed cooling system operates efficiently and the proposed self-cooling method can be used for other axial flux machines, too.
研究探讨了新型低功率发电机的传热问题。设计并实现了发电机的自冷却机制，通过发电机转子上的风扇进行强制对流。此外，空气通过定子和转子之间的气隙自然流向机器的侧面部分。设计的风扇有 16 片叶片，叶片角度为 65 度。CFD 和实验自冷却分析主要针对流速和温度测量。本研究的目的是比较自然对流和强制对流的传热效果。因此，除了瑞利数（Ra）、努塞尔特数（Nu）、格拉肖夫数（Gr）和雷诺数（Re）之外，还计算了自然对流和强制对流在小型绕组线圈（发电机的重要热源）上的传热项。此外，还从实验和理论上对其进行了澄清。在 300 rpm 转速下，强制对流的传热系数在 0.04 W 和 0.30 W 之间变化，自然对流的传热系数在 0.21 W 和 0.30 W 之间变化，而在 1000 rpm 转速下，强制对流的传热系数从 0.50 W 增加到 1.49 W，自然对流的传热系数从 0.02 W 增加到 0.45 W。事实证明，建议的冷却系统运行高效，建议的自冷却方法也可用于其他轴流式机器。
{"title":"Implementation of heat transfer techniques for an axial flux permanent magnet generator design","authors":"Erol Kurt, Mustafa Demirci, Mustafa İlbaş","doi":"10.1177/09576509241248213","DOIUrl":"https://doi.org/10.1177/09576509241248213","url":null,"abstract":"Heat transfer problem is explored for a new-designed low power generator. A self-cooling mechanism of the generator is designed and implemented for the forced convection via a fan being on the generator rotor. In addition, air is naturally directed towards the lateral parts of the machine in air gaps between stator and rotors. The designed fan has 16 blades with 65 degrees. The CFD and experimental self-cooling analyses are performed to focus on the flow velocities and temperature measurements. In this study, it has been aimed to compare heat transfers by the natural convection and by the forced convection. For this reason, besides Rayleigh ( Ra), Nusselt ( Nu), Grashof ( Gr) and Reynolds ( Re) numbers, heat transfer terms on the small winding coil, which is important heat source for the generator, are calculated for natural and forced convection. They are also clarified experimentally and theoretically. The heat transfer at 300 rpm varies between 0.04 W and 0.30 W by time for forced convection and varies between 0.21 W and 0.30 W by time for natural convection, whereas, it increases up at 1000 rpm from 0.50 W to 1.49 W by time for forced convection and from 0.02 W to 0.45 W by time for natural convection. It is proven that the proposed cooling system operates efficiently and the proposed self-cooling method can be used for other axial flux machines, too.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"127 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615401","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}
Pub Date : 2024-04-17DOI: 10.1177/09576509241248482
Junyang Yu, Dingding Qin, Chongjia Guo, Peng Sun, Wenguang Fu
Crosswind and angle of attack are critical factors that influence the safe operation of civil aviation engines, which are also essential criteria in the certification of civil engine airworthiness. Conducting research on the effects and mechanisms of angle of attack and crosswind on the integrated characteristics and flow field of nacelle and fan holds significant engineering value. In this study, a high-bypass-ratio turbofan engine serves as the research subject, and the influence of crosswind and angle of attack coupling on the nacelle intake and fan components is analyzed using numerical simulations. The numerical research findings indicate that both individual angle of attack and crosswind, as well as their combination, lead to a specific range of total pressure distortion in the inlet. At an angle of attack of 25°, the extent and degree of circumferential total pressure distortion formed on the aerodynamic interface exhibit minor variations under different crosswind inflow conditions. Under two operating conditions involving left crosswind and right crosswind, both characterized by an angle of attack of 25° and a wind speed of 20 m/s, the combined effects of crosswind and angle of attack on the fan and outlet guide vane (OGV) components are mainly concentrated at the blade tip. These influencing factors collectively lead to total pressure distortion in the inlet flow field, resulting in the interaction between tip leakage flow and passage shock waves. At the same angle of attack, there are differences in the impact of total pressure distortion caused by crosswinds in two directions on the fan. Under the same operating conditions, the total pressure distortion induced by the right crosswind has a greater impact on OGV.
{"title":"Numerical study on the influence of inlet distortion on integrated nacelle fans based on coupling crosswind and angle of attack","authors":"Junyang Yu, Dingding Qin, Chongjia Guo, Peng Sun, Wenguang Fu","doi":"10.1177/09576509241248482","DOIUrl":"https://doi.org/10.1177/09576509241248482","url":null,"abstract":"Crosswind and angle of attack are critical factors that influence the safe operation of civil aviation engines, which are also essential criteria in the certification of civil engine airworthiness. Conducting research on the effects and mechanisms of angle of attack and crosswind on the integrated characteristics and flow field of nacelle and fan holds significant engineering value. In this study, a high-bypass-ratio turbofan engine serves as the research subject, and the influence of crosswind and angle of attack coupling on the nacelle intake and fan components is analyzed using numerical simulations. The numerical research findings indicate that both individual angle of attack and crosswind, as well as their combination, lead to a specific range of total pressure distortion in the inlet. At an angle of attack of 25°, the extent and degree of circumferential total pressure distortion formed on the aerodynamic interface exhibit minor variations under different crosswind inflow conditions. Under two operating conditions involving left crosswind and right crosswind, both characterized by an angle of attack of 25° and a wind speed of 20 m/s, the combined effects of crosswind and angle of attack on the fan and outlet guide vane (OGV) components are mainly concentrated at the blade tip. These influencing factors collectively lead to total pressure distortion in the inlet flow field, resulting in the interaction between tip leakage flow and passage shock waves. At the same angle of attack, there are differences in the impact of total pressure distortion caused by crosswinds in two directions on the fan. Under the same operating conditions, the total pressure distortion induced by the right crosswind has a greater impact on OGV.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"7 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615523","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}
Flue gas recirculation has emerged as a promising low-NOx emission technology in advanced gas turbines, while the slower oxidation rate induced by the low oxygen content could potentially cause combustion instability. We conducted an experimental investigation in a single-nozzle swirl combustor to examine the impact of oxygen content, inlet flow rate as well as temperature on combustion instability under oxygen-lean conditions. The results show that reducing oxygen content from 23.3% to 21% leads to reduced amplitudes of pressure pulsation and exothermic pulsation, indicating improved combustion stability. However, further reduction in oxygen content to 18.6% causes a decrease in the combustion reaction rate, resulting in an increase in the amplitude of pressure pulsation. As the oxygen content drops to below 18.6%, the exothermic intensity decreases, which results in a decrease in the amplitude of pressure pulsation. Besides, under oxygen-lean conditions, increasing the inlet temperature is conducive to reducing the amplitude of pressure pulsation and enhancing combustion stability. Additionally, as the incoming flow rate increases from 7.4 to 9.9 m/s, the refined fuel atomization and improved uniformity of oil-gas mixing contributed to decreased pressure pulsation amplitude. Nonetheless, when the incoming flow rate further increases to 12 m/s, the amplitude of exothermic and pressure pulsation increases.
{"title":"Experimental study on combustion stability of a gas turbine model combustor under oxygen-lean conditions","authors":"Shunchuang Qin, Minwei Zhao, Zhihao Zhang, Hui Tang, Ningbo Zhao, Xiao Liu, Hongtao Zheng, Fuquan Deng","doi":"10.1177/09576509241246027","DOIUrl":"https://doi.org/10.1177/09576509241246027","url":null,"abstract":"Flue gas recirculation has emerged as a promising low-NOx emission technology in advanced gas turbines, while the slower oxidation rate induced by the low oxygen content could potentially cause combustion instability. We conducted an experimental investigation in a single-nozzle swirl combustor to examine the impact of oxygen content, inlet flow rate as well as temperature on combustion instability under oxygen-lean conditions. The results show that reducing oxygen content from 23.3% to 21% leads to reduced amplitudes of pressure pulsation and exothermic pulsation, indicating improved combustion stability. However, further reduction in oxygen content to 18.6% causes a decrease in the combustion reaction rate, resulting in an increase in the amplitude of pressure pulsation. As the oxygen content drops to below 18.6%, the exothermic intensity decreases, which results in a decrease in the amplitude of pressure pulsation. Besides, under oxygen-lean conditions, increasing the inlet temperature is conducive to reducing the amplitude of pressure pulsation and enhancing combustion stability. Additionally, as the incoming flow rate increases from 7.4 to 9.9 m/s, the refined fuel atomization and improved uniformity of oil-gas mixing contributed to decreased pressure pulsation amplitude. Nonetheless, when the incoming flow rate further increases to 12 m/s, the amplitude of exothermic and pressure pulsation increases.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"20 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140569495","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 objective of the paper is to investigate the internal flow characteristics inside the inducer under the gas-water condition using a combination of experiment and numerical simulations. Gas-water mixing is achieved by an annular gas mixing device and visualized by high-speed imaging technology. Meanwhile, the shear stress transport (SST) k- ω model coupled with the VOF model is applied to investigate the gas phase distribution. Numerically simulated inducer energy characteristics and internal gas-phase distribution are in good agreement with experimental data. The results show that the mixed gas-liquid flow inside the inducer exhibits three flow patterns: wavy flow, bubbly flow, and plug flow. For the wavy flow, a series of wavy structures on the blade surface and gas-pocket bubbles near the blade rim are observed. From wavy flow to bubbly flow, uniform bubble streams on the blade surface and spiraling strip bubbles near the edge of the blade are observed. For plug flow, bubble accumulation results in a bullet-shaped plug, and the strip-shaped bubbles near the blade rim are more obvious. In the same axial position of the inducer, the proportion of gas phase is increasing as the flow coefficient increases, thus affecting the inducer performance. The main frequency amplitude of the pressure pulsations gradually rise when the flow pattern changes from wavy to plug flow.
{"title":"A combined experimental and computational investigation of an inducer’s characteristics with gas-water two-phase flow","authors":"Jie Chen, Yong Wang, Houlin Liu, Lilin Lv, Yanhong Mao, Linglin Jiang","doi":"10.1177/09576509241240012","DOIUrl":"https://doi.org/10.1177/09576509241240012","url":null,"abstract":"The objective of the paper is to investigate the internal flow characteristics inside the inducer under the gas-water condition using a combination of experiment and numerical simulations. Gas-water mixing is achieved by an annular gas mixing device and visualized by high-speed imaging technology. Meanwhile, the shear stress transport (SST) k- ω model coupled with the VOF model is applied to investigate the gas phase distribution. Numerically simulated inducer energy characteristics and internal gas-phase distribution are in good agreement with experimental data. The results show that the mixed gas-liquid flow inside the inducer exhibits three flow patterns: wavy flow, bubbly flow, and plug flow. For the wavy flow, a series of wavy structures on the blade surface and gas-pocket bubbles near the blade rim are observed. From wavy flow to bubbly flow, uniform bubble streams on the blade surface and spiraling strip bubbles near the edge of the blade are observed. For plug flow, bubble accumulation results in a bullet-shaped plug, and the strip-shaped bubbles near the blade rim are more obvious. In the same axial position of the inducer, the proportion of gas phase is increasing as the flow coefficient increases, thus affecting the inducer performance. The main frequency amplitude of the pressure pulsations gradually rise when the flow pattern changes from wavy to plug flow.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"92 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140569374","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}
Pub Date : 2024-04-01DOI: 10.1177/09576509241242907
Ying-li Zhang, Xiang-ji Yue, Fan Yang, Jia-nan Ding, Jia-hua Hong, De-chun Ba
The scroll compressor is a kind of positive-displacement compressor applied in refrigeration systems, heat pump systems, and air conditioner systems. Using the spring smoothing method and considering the heat transfer, the numerical simulation model of the scroll compressor is established under standard working conditions. The results show that the CFD model is well validated by the experiment result. The compressor performance and the working process are analyzed. The pre-compression and the over-compression phenomenon are also studied. Moreover, the temperature distribution and velocity distribution of gas flow in the compressor are illustrated. The result shows that the pre-compression can improve the performance of the scroll compressor and the optimization of the suction channel geometry can provide a smoother suction process. Under the combined effect of the pre-compression and heat transfer, the refrigerating capacity is increased by approximately 0.54 kW and the volume efficiency is increased by approximately 2.2%. The additional power loss due to over-compression is 47.6615 W, and the setting of over-compression discharges can reduce the pressure and power loss. This study is helpful to the performance prediction and the structural optimization of the scroll compressor.
{"title":"Transient flow and thermodynamics analysis of a scroll compressor based on CFD","authors":"Ying-li Zhang, Xiang-ji Yue, Fan Yang, Jia-nan Ding, Jia-hua Hong, De-chun Ba","doi":"10.1177/09576509241242907","DOIUrl":"https://doi.org/10.1177/09576509241242907","url":null,"abstract":"The scroll compressor is a kind of positive-displacement compressor applied in refrigeration systems, heat pump systems, and air conditioner systems. Using the spring smoothing method and considering the heat transfer, the numerical simulation model of the scroll compressor is established under standard working conditions. The results show that the CFD model is well validated by the experiment result. The compressor performance and the working process are analyzed. The pre-compression and the over-compression phenomenon are also studied. Moreover, the temperature distribution and velocity distribution of gas flow in the compressor are illustrated. The result shows that the pre-compression can improve the performance of the scroll compressor and the optimization of the suction channel geometry can provide a smoother suction process. Under the combined effect of the pre-compression and heat transfer, the refrigerating capacity is increased by approximately 0.54 kW and the volume efficiency is increased by approximately 2.2%. The additional power loss due to over-compression is 47.6615 W, and the setting of over-compression discharges can reduce the pressure and power loss. This study is helpful to the performance prediction and the structural optimization of the scroll compressor.","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"50 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140569496","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}
Pub Date : 2024-03-27DOI: 10.1177/09576509241238035
{"title":"Erratum to “Characteristics of the axial compressor with different stator gaps in compressed air energy storage system”","authors":"","doi":"10.1177/09576509241238035","DOIUrl":"https://doi.org/10.1177/09576509241238035","url":null,"abstract":"","PeriodicalId":20705,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy","volume":"14 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140312817","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}
Pub Date : 2024-03-20DOI: 10.1177/09576509241238273
Ankit Bhai Patel, K Viswanath
Literature indicates that there is lack of study related to the effects of axially skewed blades on the aerodynamic performance of axial flow fans. In this study rotors of various blade skews, namely, axial, circumferential and axial-circumferential types, are studied and their aerodynamic performances are compared to those of the baseline radial rotors of two types, namely, constant chord and varying chord. The skew in a blade can be considered as combination of sweep and dihedral. The skew change from the circumferential to axial type causes reversal of dihedral induced radial blade force and hence a reversal of meridional streamline curvature which in turn reverses the modulation of the end-wall loads. The inherent forward sweep in the forward skewed blades also modulates hub and tip loads. Thus, in a forward axial skew blade the forward sweep and positive dihedral combine favorably to unload the tip and to upload the hub. In the forward circumferentially skewed blades, forward sweep and the negative dihedral have mutually countering effects on end-wall load modulation. The highlight of this study is that it has demonstrated experimentally the unloading of the tip in the forward axially skewed blades which resulted in reduced losses and better performance including increased stall margin. Reduced tip loading was also verified from the casing pressure sensor measurements which showed weakening of tip vortex. The relative influence of sweep and dihedral on performance was additionally demonstrated in the axially-circumferentially skewed rotor of the constant chord type, with improvements attributable to higher sweep.
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