Temperature Field Study on the of Natural Convection and Its Effect on the Critical Speeds in a High Pressure Rotor System

The coupling fluid flow-thermal model of natural convection heat in a High-Pressure Rotor (HPR) of the aero engine was established with Computational Fluid Dynamics (CFD) method. The temperature distributions and flow fields of the HPR with different shutdown time were studied. Then, the temperature distributions of the HPR during the hot start-up with different shutdown time were calculated. Moreover, the effects of hot start-up and shutdown temperature fields on the critical speeds of the HPR were carried out. The results show that the flow rule in the cavity of HPR is different from that in a quadrate cavity and presents diversity and complexity of flow. During 40-90 min of shutdown time, the temperature difference of the HPR is more than 20°C. When the shutdown time reaches to 60 min, the first critical speed of the HPR is decreased by 22.3% from 2256 to 1768 rpm.