Dynamics of the Fluid-Structure Coupling Model of a Direct-Acting Relief Valve

To explain the sudden jump of pressure for a direct-acting relief valve used by torpedo pump as the variation of water depth, a 2-DOF fluid-structure coupling dynamic model is developed. A nonlinear differential pressure model at valve port is applied to model the axial vibration of fluid, and a nonlinear wake oscillator model is used to excite the valve element in the vertical direction; meanwhile, the contact nonlinearity between the valve element and valve seat is also taken into consideration. Based on the developed dynamical model, the water depths for the sudden jumps of pressure can be located precisely when compared with the experimental signals, and the corresponding vibration conditions of the valve element in both the axial and vertical directions are explored. Subsequently, in order to eliminate the sudden jumps of pressure, the result of numerical simulation suggests to decrease the pump inlet pressure from 0.8 MPa to 0.4 MPa, which is verified to be effective by the corresponding experimental test, and thus the proposed dynamical model is further verified.