应用于有机朗肯循环的新型小流量低转速离心膨胀机特性研究
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摘要
相对于向心式膨胀机动辄数万转的转速,离心式透平能在较低的转速条件下实现较高的功率输出。本文以适用于有机朗肯循环(ORC)的某小流量低转速离心式透平膨胀机为研究对象,以R134a作为工作介质,用数值模拟的方法对新型透平膨胀机的气动特性进行了研究;采用CFX软件计算了该膨胀机在3 000 r/min转速下的工作特性曲线,并重点分析了在膨胀比1.7的工况下,叶片不同叶高位置的速度分布、表面压力分布、压力损失系数以及动叶内部流场马赫数云图。结果表明:该膨胀机能够在3 000 r/min转速下实现4.0的膨胀比,因此有效降低了轴承的转速和负荷;然而,由于静叶叶型设计不合理,静叶流道内出现了堵塞现象,同时叶顶间隙对动叶性能有较大的影响,这些均对离心膨胀机的性能产生了影响。本文研究结果将为离心式膨胀机的优化改进提供理论基础。
Compared with the concentric expander which always has very high rotating speed, the centrifugal turbine can achieve higher power output at a lower rotational speed. This article takes a new type of centrifugal expander with small flow rate and low rotating speed which is suitable for organic Rankine cycle(ORC) system as the research object, to study the aerodynamic characteristics. The new centrifugal expander applies R134a as the working fluid, its performance curve at 3 000 r/min is numerically investigated by the CFX software. The velocity distribution, surface pressure distribution, pressure loss coefficient and Mach cloud of internal flow field in the rotor blade are analyzed at the total pressure expansion ratio of 1.7. The results show that, the centrifugal expander can achieve the total pressure expansion ratio of 4.0 at 3 000 r/min while effectively reducing the bearing speed and loading. The choked flow phenomenon occurs in the stator blade flow channels because the blade type is not well designed. The performance of the centrifugal expander is deteriorated by the occurrence of the leakage flow of the rotor. The numerical results can be used to further optimize the centrifugal expander.
Compared with the concentric expander which always has very high rotating speed, the centrifugal turbine can achieve higher power output at a lower rotational speed. This article takes a new type of centrifugal expander with small flow rate and low rotating speed which is suitable for organic Rankine cycle(ORC) system as the research object, to study the aerodynamic characteristics. The new centrifugal expander applies R134a as the working fluid, its performance curve at 3 000 r/min is numerically investigated by the CFX software. The velocity distribution, surface pressure distribution, pressure loss coefficient and Mach cloud of internal flow field in the rotor blade are analyzed at the total pressure expansion ratio of 1.7. The results show that, the centrifugal expander can achieve the total pressure expansion ratio of 4.0 at 3 000 r/min while effectively reducing the bearing speed and loading. The choked flow phenomenon occurs in the stator blade flow channels because the blade type is not well designed. The performance of the centrifugal expander is deteriorated by the occurrence of the leakage flow of the rotor. The numerical results can be used to further optimize the centrifugal expander.
引文
[1]姜亮,朱亚东,徐建,等.低温余热发电系统中涡轮膨胀机的优化研究[J].节能技术,2012,30(5):400-404.JIANG Liang,ZHU Yadong,XU Jian,et al.Optimization study of turbo-expander in power generation system recovering low-temperature waste heat[J].Energy Conservation Technology,2012,30(5):400-404.
[2]刘易霖,吴钦木,陈湘萍.浅谈利用中低品位热源的有机朗肯循环发电技术[J].节能技术,2017,35(1):12-15.LIU Yilin,WU Qinmu,CHEN Xiangping.Discussion on ORC power generation technologies by applying low/medium grade thermal sources[J].Energy Conservation Technology,2017,35(1):12-15.
[3]潘登,高乃平,谢飞博,等.有机朗肯循环涡旋膨胀机性能试验研究[J].流体机械,2014,42(5):10-14.PAN Deng,GAO Naiping,XIE Feibo,et al.Experimental research on the performance of scroll expander used in organic Rankine cycle[J].Fluid Machinery,2014,42(5):10-14.
[4]刘茜,刘莉娜,王令宝,等.采用涡轮膨胀机的有机朗肯循环系统优化[J].新能源进展,2017,5(1):23-31.LIU Xi,LIU Lina,WANG Lingbao,et al.Optimization of an organic Rankine cycle system with turboexpander[J].Advances in New and Renewable Energy,2017,5(1):23-31.
[5]马新灵,孟祥睿,魏新利,等.有机朗肯循环低品位热能发电系统向心透平的设计与性能研究[J].中国电机工程学报,2014,34(14):2289-2296.MA Xinling,MENG Xiangrui,WEI Xinli,et al.Design and performance study of radial inflow turbine used on organic Rankine cycle waste heat power generation system[J].Proceedings of the CSEE,2014,34(14):2289-2296.
[6]孙志强,易思阳,郭美茹,等.利用中低温余热的回热有机朗肯循环性能分析[J].热能动力工程,2015,30(1):24-30.SUN Zhiqiang,YI Siyang,GUO Meiru,et al.Performance analysis of regenerative organic Rankine cycle using low and medium temperature residual heat[J].Thermal Energy Engineering,2015,30(1):24-30.
[7]王大彪,段捷,胡哺松,等.有机朗肯循环发电技术发展现状[J].节能技术,2015,33(3):235-242.WANG Dabiao,DUAN Jie,HU Busong,et al.Status of organic Rankine cycle power generation technology[J].Energy Conservation Technology,2015,33(3):235-242.
[8]PINI M,PERSICO G,CASATI E,et al.Preliminary design of a centrifugal turbine for organic Rankine cycle applications[J].Journal of Engineering for Gas Turbines&Power,2013,135(4):110.
[9]PERSICO G,PINI M,DOSSENA V,et al.Aerodynamic design and analysis of centrifugal turbine cascades[C]//ASME Turbo Expo.2013:V06CT40A019.
[10]PERSICO G,PINI M,DOSSENA V,et al.Aerodynamics of centrifugal turbine cascades[J].Journal of Engineering for Gas Turbines&Power,2015,137(11):112602(1-11).
[11]PINI M,SPINELLI A,PERSICO G,et al.Consistent look-up table interpolation method for real-gas flow simulations[J].Computers&Fluids,2015,107:178-188.
[12]BAHAMONDE S,PINI M,SERVI C D,et al.Active subspaces for the optimal meanline design of unconventional turbomachinery[J].Applied Thermal Engineering,2017,127:1108-1118.
[13]李银各,谭鑫,林显巧,等.离心式透平的热力设计与分析[J].工程热物理学报,2016,37(10):2103-2109.LI Yinge,TAN Xin,LIN Xianqiao,et al.Thermal design and analysis of centrifugal turbine[J].Journal of Engineering Thermophysics,2016,37(10):2103-2109.
[14]刘菁,单鹏.分立式导向器离心涡轮气动改型设计与流场分析[J].航空动力学报,2008(6):1047-1053.LIU Jing,SHAN Peng.Pneumatic retrofit design and flow field analysis of centrifugal turbine with discrete guide[J].Journal of Aerospace Power,2008(6):1047-1053.
[15]李昀竹,裴刚,李晶,等.小型涡轮在有机朗肯循环系统中的性能测试与分析[J].热能动力工程,2012,27(1):28-32.LI Yunzhu,PEI Gang,LI Jing,et al.Performance test and analysis of small turbine in organic Rankine cycle system[J].Thermal Energy Engineering,2012,27(1):28-32.
[16]李艳,连红奎,顾春伟.有机朗肯循环系统及其透平设计研究[J].工程热物理学报,2010,31(12):2014-2018.LI Yan,LIAN Hongkui,GU Chunwei.Design and study of organic Rankine cycle(ORC)and turbine for ORC[J].Journal of Engineering Thermophysics,2010,31(12):2014-2018.
[17]曾军,王丽.某5级低压涡轮全三维计算分析[J].航空动力学报,2012,27(7):1441-1447.ZENG Jun,WANG Li.Full three-dimensional computational analysis of a 5-stage low-pressure turbine[J].Aviation Dynamics Daily,2012,27(7):1441-1447.
[18]曹惠玲,欧金平.基于CFX的涡轮叶片流场及温度场的数值模拟[J].中国民航大学学报,2014,32(5):11-14.CAO Huiling,OU Jinping.Numerical simulation of flow field and temperature field of turbine blade based on CFX[J].Journal of China Civil Aviation University,2014,32(5):11-14.
[19]NITHESH K G,CHATTERJEE D,CHEOL O H,et al.Design and performance analysis of radial-inflow turbo expander for OTEC application[J].Renewable Energy,2016,85(1):834-843.
[2]刘易霖,吴钦木,陈湘萍.浅谈利用中低品位热源的有机朗肯循环发电技术[J].节能技术,2017,35(1):12-15.LIU Yilin,WU Qinmu,CHEN Xiangping.Discussion on ORC power generation technologies by applying low/medium grade thermal sources[J].Energy Conservation Technology,2017,35(1):12-15.
[3]潘登,高乃平,谢飞博,等.有机朗肯循环涡旋膨胀机性能试验研究[J].流体机械,2014,42(5):10-14.PAN Deng,GAO Naiping,XIE Feibo,et al.Experimental research on the performance of scroll expander used in organic Rankine cycle[J].Fluid Machinery,2014,42(5):10-14.
[4]刘茜,刘莉娜,王令宝,等.采用涡轮膨胀机的有机朗肯循环系统优化[J].新能源进展,2017,5(1):23-31.LIU Xi,LIU Lina,WANG Lingbao,et al.Optimization of an organic Rankine cycle system with turboexpander[J].Advances in New and Renewable Energy,2017,5(1):23-31.
[5]马新灵,孟祥睿,魏新利,等.有机朗肯循环低品位热能发电系统向心透平的设计与性能研究[J].中国电机工程学报,2014,34(14):2289-2296.MA Xinling,MENG Xiangrui,WEI Xinli,et al.Design and performance study of radial inflow turbine used on organic Rankine cycle waste heat power generation system[J].Proceedings of the CSEE,2014,34(14):2289-2296.
[6]孙志强,易思阳,郭美茹,等.利用中低温余热的回热有机朗肯循环性能分析[J].热能动力工程,2015,30(1):24-30.SUN Zhiqiang,YI Siyang,GUO Meiru,et al.Performance analysis of regenerative organic Rankine cycle using low and medium temperature residual heat[J].Thermal Energy Engineering,2015,30(1):24-30.
[7]王大彪,段捷,胡哺松,等.有机朗肯循环发电技术发展现状[J].节能技术,2015,33(3):235-242.WANG Dabiao,DUAN Jie,HU Busong,et al.Status of organic Rankine cycle power generation technology[J].Energy Conservation Technology,2015,33(3):235-242.
[8]PINI M,PERSICO G,CASATI E,et al.Preliminary design of a centrifugal turbine for organic Rankine cycle applications[J].Journal of Engineering for Gas Turbines&Power,2013,135(4):110.
[9]PERSICO G,PINI M,DOSSENA V,et al.Aerodynamic design and analysis of centrifugal turbine cascades[C]//ASME Turbo Expo.2013:V06CT40A019.
[10]PERSICO G,PINI M,DOSSENA V,et al.Aerodynamics of centrifugal turbine cascades[J].Journal of Engineering for Gas Turbines&Power,2015,137(11):112602(1-11).
[11]PINI M,SPINELLI A,PERSICO G,et al.Consistent look-up table interpolation method for real-gas flow simulations[J].Computers&Fluids,2015,107:178-188.
[12]BAHAMONDE S,PINI M,SERVI C D,et al.Active subspaces for the optimal meanline design of unconventional turbomachinery[J].Applied Thermal Engineering,2017,127:1108-1118.
[13]李银各,谭鑫,林显巧,等.离心式透平的热力设计与分析[J].工程热物理学报,2016,37(10):2103-2109.LI Yinge,TAN Xin,LIN Xianqiao,et al.Thermal design and analysis of centrifugal turbine[J].Journal of Engineering Thermophysics,2016,37(10):2103-2109.
[14]刘菁,单鹏.分立式导向器离心涡轮气动改型设计与流场分析[J].航空动力学报,2008(6):1047-1053.LIU Jing,SHAN Peng.Pneumatic retrofit design and flow field analysis of centrifugal turbine with discrete guide[J].Journal of Aerospace Power,2008(6):1047-1053.
[15]李昀竹,裴刚,李晶,等.小型涡轮在有机朗肯循环系统中的性能测试与分析[J].热能动力工程,2012,27(1):28-32.LI Yunzhu,PEI Gang,LI Jing,et al.Performance test and analysis of small turbine in organic Rankine cycle system[J].Thermal Energy Engineering,2012,27(1):28-32.
[16]李艳,连红奎,顾春伟.有机朗肯循环系统及其透平设计研究[J].工程热物理学报,2010,31(12):2014-2018.LI Yan,LIAN Hongkui,GU Chunwei.Design and study of organic Rankine cycle(ORC)and turbine for ORC[J].Journal of Engineering Thermophysics,2010,31(12):2014-2018.
[17]曾军,王丽.某5级低压涡轮全三维计算分析[J].航空动力学报,2012,27(7):1441-1447.ZENG Jun,WANG Li.Full three-dimensional computational analysis of a 5-stage low-pressure turbine[J].Aviation Dynamics Daily,2012,27(7):1441-1447.
[18]曹惠玲,欧金平.基于CFX的涡轮叶片流场及温度场的数值模拟[J].中国民航大学学报,2014,32(5):11-14.CAO Huiling,OU Jinping.Numerical simulation of flow field and temperature field of turbine blade based on CFX[J].Journal of China Civil Aviation University,2014,32(5):11-14.
[19]NITHESH K G,CHATTERJEE D,CHEOL O H,et al.Design and performance analysis of radial-inflow turbo expander for OTEC application[J].Renewable Energy,2016,85(1):834-843.