氦透平膨胀机相似模化方法分析与实验验证  

Analysis and Experimental Verification of Similitude Modeling Method for Helium Turbo-expander

作　　者：张泽[1,2] 周楷淼[1] 付豹 陈双涛[1,2] 陈良[1,2] 侯予 ZHANG Ze;ZHOU Kaimiao;FU Bao;CHEN Shuangtao;CHEN Liang;HOU Yu(School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China;MOE key Laboratory of Cryogenic Technology and Equipment,Xi'an 710049,China;Institute of Plasma Physics,China Academy of Sciences,Hefei 230031,China)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049 [2]深低温技术与装备教育部重点实验室,西安710049 [3]中国科学院等离子体物理研究所,合肥230031

出　　处：《真空与低温》2023年第5期498-503,共6页Vacuum and Cryogenics

基　　金：国家自然科学基金(U21B2084)。

摘　　要：由于氦透平膨胀机在设计工况下进行低温性能测试的实验平台和配套设施很难满足要求,且低温工况较难达到,因此通常用膨胀机在空气中的实验来检验其性能,并通过相似模化方法得到膨胀机低温下的性能。通过分析工质在透平膨胀机中的流动及能量转化过程,发现特性比U1/CS、膨胀比P1/P2、马赫数Ma、雷诺数Re是影响膨胀机性能的关键参数。结合相似理论,以透平膨胀机变工况性能预测程序计算结果为依据,筛选出了以U1/CS为第一相似准则,以Ma、k^(−1)·Ma^(−2)、Ma·k^(−1)、k·Ma^(2)作为第二相似准则的四组相似准则数。以流体动力学计算结果为依据,从四组相似准则中选择出了模化误差最小的相似准则,即U1/CS与Ma·k^(−1)组合。结果表明:相似模化前后氦气与空气透平膨胀机间等熵效率的最大误差在±1.4%以内,且在内部流场预测(马赫数、速度分布)等方面具有良好的模化效果;氦透平膨胀机在设定工况下和空气透平膨胀机在相似模化工况下的等熵效率实验数据显示,两者变化趋势一致且误差小于1%。Because the test platform and supporting facilities for cryogenic performance testing of helium turbo-expanders under design conditions are difficult to meet,and the design conditions are difficult to achieve,the expander is usually tested in air to test its performance,and then the performance of the expander at cryogenic temperature is obtained by similarity modeling method.By analyzing the flow and energy conversion process of the working fluid in the turbo-expander,it is found that the characteristic ratio U1/CS,expansion ratio P1/P2,Mach number Ma,and Reynolds number Re are the key parameters that affect the performance of the expander.Based on similar theories and the calculation results of the turbo-expander performance prediction program under variable conditions,four groups of similarity criteria were selected with U1/CS as the first similarity criterion and Ma,k^(−1) Ma^(−2),Ma·k^(−1),k·Ma^(2) as the second similarity criterion.Based on the calculation results of computational fluid dynamics,the similarity criterion with the smallest modeling error is selected from the four sets of similarity criteria,namely the combination of U1/CS and Ma·k^(−1).Theoretical calculation results show that the maximum error of isentropic efficiency between helium and air turbo-expanders before and after similar modeling is within±1.4%,and it also has a good model in terms of internal flow field prediction(Mach number,velocity distribution),etc.Finally,experimental data of isentropic efficiency of helium turbo-expander under set working conditions and air turbo-expander under similar modeling conditions show that the variation trend is consistent,and the error is less than 1%.

关 键 词：氦气 透平膨胀机 相似理论 变工质 

分 类 号：TB653[一般工业技术—制冷工程]