微型气浮轴承高速透平膨胀机的研制

study of Miniature High Speed Turboexpander with Gas Lubricated Bearing

为了发展微型气体轴承高速透平,在优化设计的基础上,研制了国内首台轴径为6 mm、叶轮直径为9 mm、设计转速为300 000 r/min的微型气体轴承透平膨胀机.对研制样机进行了全面介绍,阐述了该研制样机的结构设计特点,并对研制样机进行了初步的机械性能和热力性能考核.通过转子起浮试验,系统机械性能、热力性能的连续运转及超速试验考核,结果显示:所研制的样机振动小、运转平稳、效率高,最高转速超过342 000 r/min,满足超速15%的要求;在室温为23℃、无回热器的情况下,当进气压力从0升到0.27 MPa的45 min升速时间内,温降就达42℃,具有降温速度快,降温效果显著的特点.由于其机械及热力性能均达到预期要求,因此为今后进一步发展我国微型高速气体轴承透平机械奠定了坚实基础.

A new miniature static gas bearing turboexpander with a shaft diameter of 6mm,a wheel diameter of 9mm,and a designed rotation speed of 300 000 r/min was developed on the basis of optimum design.The structure characteristics of the prototype developed were investigated.The preliminary mechanical and thermodynamic performance of the prototype was experimentally examined.The results show that the prototype has obvious features such as small vibration,stable operation and high efficiency,and the prototype can run at more than 342 000 r/min reaching 15% over-speed.Moreover,the temperature drop can be 42 ℃ within 45 minutes when the driving pressure increases from 0 to 0.27 MPa at the room temperature of 23 ℃ for the prototype without recuperators.The experimental verification shows that the mechanical and thermodynamic performance of the prototype can meet the requirement.