Study of Hydrodnamic Pumping Effects of Fixed Axis Rotation in Eccentric Annular Flow Field

Hydrodynamic effect is one of the key phenomena in journal bearing lubrication. Many researches have been carried out on the supporting force of journal bearing, the motion of suspension shaft and the lubrication effect. This paper studies the hydrodynamic effect from another point of view, that is, the pumping effect caused by the rotation of the eccentric shaft with fixed axis. The clearance between the rotor and the stator is divided into two sections by the inlet port and the outlet port. Their mathematical models are established and studied in polar coordinates. The pressure distribution and pumping flowrate in the flow field are studied theoretically. Under the conditions analyzed in this paper, an output flow larger than 90 ml/s could be generated, overcoming a load pressure of 0.5 MPa. In addition, the pressure distribution and pumping flowrate of the mechanism are affected by the pumping outlet orientation. According to the analysis results of the output angle range from π/8 to 3π/4, when the pump outlet angle is set near 3π/8 to π/2, the pumping flowrate reaches the maximum value of 91.83 ml/s, and nearly half 48% of the inflow liquid can be pumped out to the outlet.