Packaging and testing of high speed rotor for MEMS gas turbine engines

A micro rotor with high rotation speed is of vital importance for MEMS gas turbine engine to achieve its higher power density and transfer energy with high efficiency. In this investigation, a micro silicon rotor, which is fabricated by one-time multi-depth silicon etching method and supported by a 3-wafers bearing system, is completed to reach high rotation speed. To ensure wafer bonding quality, a non-destructive method based on analyzing infrared images through multilayer wafers is proposed and practiced. After the rotor and its bearing system are packaged successfully, a platform which consists of the rotor, the 3-wafers bearing system, air supply and control systems is established for testing and optimizing performance of the high speed micro rotor. The platform's control scheme is closed-loop and is based on the principle of stiffness changing, in which the stiffness of the bearing system is varied by adjusting inlet pressure based on the rotation speed.