Study of miniature high speed turboexpander with gas lubricated bearing

A new miniature static gas bearing turboexpander with a shaft diameter of 6 mm, a wheel diameter of 9 mm, and a designed rotation speed of 300000 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 342000 r/min reaching 15% over-speed. Moreover, the temperature drop can be 42°C within 45 minutes when the driving pressure increases from 0 to 0.27 MPa at the room temperature of 23°C for the prototype without recuperators. The experimental verification shows that the mechanical and thermodynamic performance of the prototype can meet the requirement.