低温氦气向心透平变工况特性研究
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摘要
以低温氦气为流动工质,采用实际气体模型计算工质物性,进行低温氦气向心透平的气动设计与性能研究。运用数值模拟方法,对所设计的氦气透平膨胀机进行设计和非设计工况下的三维稳态流场分析。结果显示:在设计工况下,流道内的流场合理,气动性能符合设计要求;在变工况条件下,随着转速的增大,效率先增大后减小,在设计转速时最大。漩涡的出现会导致透平效率迅速下降。当转速一定时,随着膨胀比的增大,质量流量近似线性的增大,效率先增大后减小,在设计膨胀比时最大;转速的减小可使最大效率点对应的膨胀比减小;转速的变化对流量几乎没有影响;随着入口温度增大,质量流量逐渐降低,效率先增大后降低,在设计入口温度下最大。
The aerodynamic design and performance research of a radial-flow turbine stage were conducted using cryogenic helium as the flow medium and using real gas model for calculation of the physical properties of the working medium. Based on the CFD simulation method,the analysis of three-dimensional steady-state flow field for the designed cryogenic helium radial inflow turboexpander stage was carried out under both the design and off-design conditions. The results show that: under the design conditions, the flow field was reasonable in the flow path and the aerodynamic performance met the design requirements. Under the off-design conditions,the efficiency first increased and then decreased with the increase of rotating speed and achieved maximum at the design rotating speed. The appearance of vortex would lead to the rapid decline of the efficiency of the turboexpander under the off-design conditions. When the rotating speed is constant,the mass flow rate increased linearly with the increase of expansion ratio,and the efficiency increased at first,then decreased and achieved maximum at the design expansion ratio. The decrease of rotating speed can make the expansion ratio reduced corresponding to the maximum efficiency point. The change of rotating speed had little influence on flow rate. The mass flow rate decreased gradually with the increase of inlet temperature,and the efficiency first increased,then decreased and achieved maximum at the design inlet temperature.
The aerodynamic design and performance research of a radial-flow turbine stage were conducted using cryogenic helium as the flow medium and using real gas model for calculation of the physical properties of the working medium. Based on the CFD simulation method,the analysis of three-dimensional steady-state flow field for the designed cryogenic helium radial inflow turboexpander stage was carried out under both the design and off-design conditions. The results show that: under the design conditions, the flow field was reasonable in the flow path and the aerodynamic performance met the design requirements. Under the off-design conditions,the efficiency first increased and then decreased with the increase of rotating speed and achieved maximum at the design rotating speed. The appearance of vortex would lead to the rapid decline of the efficiency of the turboexpander under the off-design conditions. When the rotating speed is constant,the mass flow rate increased linearly with the increase of expansion ratio,and the efficiency increased at first,then decreased and achieved maximum at the design expansion ratio. The decrease of rotating speed can make the expansion ratio reduced corresponding to the maximum efficiency point. The change of rotating speed had little influence on flow rate. The mass flow rate decreased gradually with the increase of inlet temperature,and the efficiency first increased,then decreased and achieved maximum at the design inlet temperature.
引文
[1]付豹.EAST氦制冷机气体轴承氦透平膨胀机研制[D].北京:中国科学院大学,2015.
[2]李艳,李海波,顾春伟.有机工质向心透平气动设计与变工况性能预测[J].工程热物理学报,2013,34(1):63-66.
[3]王仲奇,秦仁.透平机械原理[M].北京:机械工业出版社,1981:143-147
[4]谭鑫,李银各,林显巧,等.离心式透平的变工况特性研究[J].工程热物理学报,2016,37(6):1201-1207.
[5]韩中合,吴伟铭,王智.有机朗肯循环向心透平变工况特性与调节方式研究[J].汽轮机技术,2014(6):417-420.
[6]Qiu X,Baines N.Performance prediction for high pressure-ratio radial inflow turbines[C].ASME Turbo Expo 2007:Power for Land,Sea and Air,2007:945-956.
[7]Sauret E,Gu Y.Three-dimensional off-design numerical analysis of an organic Rankine cycle radialinflow turbine[J].Applied Energy,2014,135(C):202-211.
[8]舒士甄.叶轮机械原理[M].北京:清华大学出版社,1991:172-175
[9]李燕生,陆桂林.向心透平与离心压气机[M].北京:机械工业出版社,1987:151-157.
[2]李艳,李海波,顾春伟.有机工质向心透平气动设计与变工况性能预测[J].工程热物理学报,2013,34(1):63-66.
[3]王仲奇,秦仁.透平机械原理[M].北京:机械工业出版社,1981:143-147
[4]谭鑫,李银各,林显巧,等.离心式透平的变工况特性研究[J].工程热物理学报,2016,37(6):1201-1207.
[5]韩中合,吴伟铭,王智.有机朗肯循环向心透平变工况特性与调节方式研究[J].汽轮机技术,2014(6):417-420.
[6]Qiu X,Baines N.Performance prediction for high pressure-ratio radial inflow turbines[C].ASME Turbo Expo 2007:Power for Land,Sea and Air,2007:945-956.
[7]Sauret E,Gu Y.Three-dimensional off-design numerical analysis of an organic Rankine cycle radialinflow turbine[J].Applied Energy,2014,135(C):202-211.
[8]舒士甄.叶轮机械原理[M].北京:清华大学出版社,1991:172-175
[9]李燕生,陆桂林.向心透平与离心压气机[M].北京:机械工业出版社,1987:151-157.