小型全动压低温透平膨胀机设计与实验研究

Design and experimental study on a small cryogenic turboexpander with aerodynamic gas bearing

通过自主研发低温空气透平膨胀机,主轴轴径为22 mm,叶轮进口直径为36.2 mm,采用径向-止推全动压箔片空气轴承。在空气制冷机实验台上对膨胀机性能进行测试,针对膨胀机通流部分开展了数值模拟,并将数值模拟与实验的结果进行了对比,模拟和实验的等熵效率变化趋势一致,平均误差为3%。在实验中,膨胀机在进口温度283.2 K,进口压力0.26 MPa的工况下,转速能稳定达到112200 r/min,流量可达0.21 kg/s,能获得7.75 kW的制冷量。

A small cryogenic air turboexpander equipped with a radial-thrust aerodynamicgas bearing was designed and developed.The journal diameter of turboexpander is 22 mm and the inlet diameter of impeller is 36.2 mm.The performance of the turboexpander was tested on an air refrigerator test rig.The numerical simulations were conducted on the flow passage of the turboexpander,and the simulated results were compared with the experimental data.The variations of isotropic efficiency of the simulations and experiments were found to be similar,and the average error between the simulation and experiment results is 3%.In the experiment,the rotating speed of the turboexpander reached 112200 r/min under the inlet temperature of 283.2 K and the inlet pressure of 0.26 MPa.At this time,the mass flow rate was 0.21 kg/s,with a cooling capacity of 7.75 kW.