Research and Experiment of Auxiliary Bearing for Helium Circulator of HTR-PM

The research and application of the unlubricated auxiliary bearing is very important in certain special circumstances, such as in the nuclear power station, aeroplane engine and so on. Active magnetic bearing (AMB) is replacing ordinary mechanical bearings as the perfect supporting scheme for the helium circulator of high-temperature gas-cooled reactor-pebble bed module (HTR-PM) of China. Because it has several advantages: free of contact, no lubrication and controllability very well, etc. The auxiliary bearing is used to support the circulator rotor when the AMB fails to work, but oil or grease can’t be applied for this auxiliary bearing. And it must support the dropping rotor and bear the great impact force and friction heat. The design of the auxiliary bearing is one of the challenging problems in the whole system. A new design plan of auxiliary bearing is proposed in this paper. This auxiliary bearing is composed of angular contact ceramic ball bearing designed by special technology. Two pairs of bearing will be distributed on both ends of the rotor. Each pair of bearing arrangement is face to face. The rotor’s length of helium circulator of HTR-PM is about 3.3 m, its weight is about 4000 kg and the rotating speed is 4000 r/min. It is difficult to analyze the falling course of the rotor. The preliminary analysis and experiment of the dropping rotor was done in this paper. The auxiliary bearing’s life will be evaluated. And the buffer shim is also studied to reduce the impact force by simulation in this paper. The scheme of auxiliary bearing and the experimental results offer the important base for this new auxiliary bearing style, and offer the protector design of the helium circulator with AMB for HTR-PM.