Analysis and experimental verification of structure-thermal running stability for micro turbojet engine rotor

For the high speed rotor of a type of micro turbojet engine, thermal running stability was analyzed firstly, then high-precision dynamic balancing and overall dynamic balance checking in thermal state, as well as the damping structure and thermal insulation, were experimentally verified. The results show that, when the rotor imbalance is reduced, the rotor is kept steady with proper external damping. The average temperature of measuring points is reduced with the installation of heat shield for back bearing, which reduces the heat input for rotor support and its effect on the bearing stiffness and damping. The methods consequently improve the structure-thermal running stability of rotor, and enhance the stability and safety of the whole engine.