Abstract：A bidirectional fluid-structure interaction simulation method for the leakage mechanism of spiral slit was proposed by using numerical simulation and data fitting method. Using this method, the deviations in the leakage calculation results of the progressing cavity pump(PCP)by the unidirectional fluid-structure interaction method and bidirectional fluid-structure interaction method were compared. The calculation results show that the smaller the gap, the greater the deviation. When the gap is 0.5 mm, the difference between the two results is 20.3%, indicating that the rigid-flexible screw pump spiral slot leakage must be solved using the bidirectional fluid-structure interaction to obtain accurate results. The finite element analysis of the three-dimensional PCP model was carried out by using the bidirectional fluid-structure interaction method. The effects of initial clearance, fluid medium viscosity, single-stage chamber pressure difference, and inlet and outlet pressure on the leakage of PCP were studied. The results show that the leakage increases with the increase of initial clearance and decreases with the increase of viscosity of the fluid medium. The influence of inlet and outlet pressure change on PCP leakage is very small and can be ignored. The pressure difference between the chambers results in the deformation of the rubber stator, which causes the gap to be formed. This sap changes linearly with the increase of the pressure difference. The volumetric efficiency of the PCP with different lifting pressures was calculated by the bidirectional fluid-structure interaction method, and the error was within ±5% when compared with the experimental results.
