NUMERICAL SIMULATION OF UNSTABLE MODES FOR A SAFETY VALVE

When designing pressure regulators, one needs to have a complete understanding of gasdynamic processes. The numerical algorithm for three-dimensional gas-dynamic modeling of a full cycle of spring safety valve operation is proposed, which allows one to significantly reduce the computing time. Grid reconfiguration during CFD modeling is provided by interpolation procedure using previously calculated grids. Calculations show that gas-dynamic numerical simulation should account for a three-dimensional structure of the unsteady flow and the motion of the disc. These factors are taken into account when calculating full cycle of the valve on a coarse grid with the use of correction functions for the force and flow characteristics of the valve. The correction functions are calculated by the false transient method in the three-dimensional formulation. Cyclograms of the valve operation demonstrate satisfactory agreement of the experimental and numerical simulation results. The agreement in the variation of gas-dynamic forces with time is observed, except for the transitional regime before the valve starts to close. In the main work area, the calculated values of the reduced force belong to a confidence interval.