Steady Flow Force Compensation and Test Research on Electrohydraulic Proportional Relief Valve

The pressure control accuracy of electrohydraulic proportional relief valve (EPRV) is affected by steady flow force. Thus, this paper investigates the method of designing a spool groove into the turbine bucket profile to compensate for the steady flow force maximally. The influence of steady flow force on the working pressure of the EPRV is analyzed. The calculation model of the steady flow force is deduced. Moreover, the computational fluid dynamics (CFD) model of the spool is established considering the fitting clearance between the spool and the valve body. The test bench is built to verify the CFD model. The turbine bucket profile is designed in the spool groove and optimized on the basis of the response surface method. Furthermore, the flow impact coefficient is defined and the compensation effect of the optimized spool to the steady flow force is tested. The results show that the absolute error value of the CFD simulation and test is smaller than 6.51%. When the working pressure is 0.5, 2, and 4 MPa, the flow impact coefficients of the optimized spool can be reduced by 100%, 59.15%, and 26.72%, respectively, compared with the original spool, indicating that the optimized spool can obviously compensate the steady flow force and improve the control accuracy of the EPRV.