Study on heat transfer performance of shaft seal in HTR-PM circulator

For HTR-PM circulator, it is vertical layout. Its impeller is coaxial with the motor, the impeller locates in bottom chamber and the motor locates in upper chamber. Impeller works in high temperature up to 300℃, but motor cannot work in temperature over 150℃. Therefore, the shaft runs through both high-temperature zone and low-temperature zone. A kind of separator structure is designed to separate these two temperature zones. A shaft seal is needed to lay between the rotary shaft and the stationary separator structure. Its role is to reduce leakage, prevent high-temperature gas from leaking to low-temperature zone, and then ensures the normal operation of motor and other electrical components. For the shaft seal of HTR-PM circulator, its inlet temperature is much higher than usual rotatory seals and its outlet temperature is much lower than the inlet temperature. High temperature has great influence on the performance of the shaft seal. Some related numerical studies will be described. It would be helpful to optimize the performance and design of the shaft seal. (author)