STUDY ON BALANCE OF AXIAL FORCE IN HELIUM CIRCULATOR FOR HTR-PM

摘要

The helium circulator is one of the key equipment in the first loop of the High Temperature gas-cooled Reactor Pebble bed Module (HTR-PM) The active magnetic bearings are employed in the helium circulator, so that the inlet ring sealing clearance is about 5 to 10 times larger than that if the mechanical bearings are employed Bigger clearance results in bigger leakage flow and bigger axial force A new design of balance holes was proposed to reduce the axial aerodynamic force and the design principle was analyzed To investigate the axial aerodynamic force due to leakage flow, numerical simulation of fluid dynamic was conducted in the impeller with two kinds of inlet ring sealing clearance and four types of balance holes, respectively The calculation results shows that the balance holes with diameter 12mm have high performance and that the designed balance holes reduce effectively about 78% of the axial aerodynamic force The axial force was obtained from the measured real-time electric current of the axial active magnetic bearings in one helium circulator prototype The comparison of experimental data with the CFD analysis results showed that the new design of balance holes was successful