Numerical Simulation And Optimal Design Of Spring Safety Valve Based On CFD

Pressure relief valve(PRV)is an important component in the pressure-bearing equipment.The normal operation of the safety valve is of great significance to the life and reliability of the entire pressure-bearing system.This paper mainly uses a combination of numerical simulation and experimental research to study the lift force and outlet flow of the PRV.Through research,a turbulence model that can be used to predict the valve disc lift and outlet flow of the safety valve is determined and used for subsequent safety valves optimized design of valve disc structure.I hope that the research in this paper can provide some help to the engineering designers of safety valves.The research content of this paper is as follows:(1)A two-dimensional CFD model of the PRV was established.And the six turbulence models in the Fluent software were used to predict the lift force and outlet flow at different valve disc openings.The prediction results show that the lift force errors predicted by the six turbulence models at small openings are small,but the prediction errors at medium and large openings are large.There is not much difference in the prediction of the outlet flow of the pressure relief valve between the six turbulence models,but the difference between the predicted outlet flow under the large opening degree and the predicted outlet flow under the small opening degree is smaller.(2)A test device for the lift force of the PRV was built,and a data acquisition system for the test device was written based on LabVIEW.The test results show that the test device has good repeatability and can accurately measure the lift force of the safety valve at different pressures and different valve disc openings.Through the test device,the lift force at different valve disc openings at the inlet pressures of 3.0 bar,3.5 bar,and 4.0 bar were measured.By comparing the test data and the simulation data,the error of the SST(4eq)turbulence model was found to be the smallest.The RKE turbulence model has the largest error.Therefore,it is determined that the SST(4eq)turbulence model has the highest accuracy among the six turbulence models.The turbulence model can predict the lift force and outlet flow at different pressures and different valve disc openings,which can be used for the subsequent optimal design of the valve disc structure.(3)An optimized model of the valve disc structure of the safety valve was established to optimize the design of the valve disc of the safety valve,with the outlet flow of the safety valve as the objective function,and the valve disc radius,valve disc depth and valve discthickness of the safety valve as design variables.And the Latin hypercube sampling(LHS)method was used for experimental design and CFD simulation of the design point was used to obtain the outlet flow of the design point.The RBF model was used to fit the test point data,and the genetic algorithm was used to optimize the fitted model.The CFD calculation of the optimized structure was re-calculated,and the results showed that the outlet flow of the optimized design safety valve increased by 21.43% compared with the original design,which can accelerate the discharge of the medium in the pressure equipment.