Sensitivity Analysis And Optimization Design Of Structure Parameters Of Labyrinth Control Valve

Control Valve is an important control element widely used in industrial processes such as pipeline transportation,petrochemical industry,hydropower and nuclear power.Its quality directly determines whether the entire system control process is timely and effective.Labyrinth control valve is a regulator valve with multi-stage pressure reduction.The labyrinth flow channel structure on the disc of the valve core can make the labyrinth control valve have some good characteristics under the working condition of high pressure difference,such as anticavitation,noise reduction and vibration reduction,which can improve the reliability and service life of the valve.In order to clearly understand the flow characteristics of the local flow field in the labyrinth control valve and the influence of the structural parameters of the labyrinth path on the pressure reduction effect,the Computational Fluid Dynamics(CFD)method was used in this paper to carry out a simulation of the internal flow field of half geometric model of the labyrinth control valve.And the flow characteristics of the local flow field in the labyrinth control valve were analyzed.The results show that the local flow velocity and pressure change in the labyrinth flow path is opposite,and the fluid pressure in the flow channel of the same serial number on the disc of the valve core gradually decreases from the disc 1 to the disc 10,and the fluid speed is reduced first and then increased;In the valve core of the labyrinth control valve,the mass flow rate of the fluid increases exponentially from disc 1 to disc 10,but the value of the flow coefficient between the discs in the valve core is approximately equal.Then,based on the related research work of the labyrinth control valve,four labyrinth path structural design parameters were selected,and a Latin Hypercube Sampling(LHS)method was applied to select 45 training sample points and 10 test sample points,and using numerical simulation to calculate the pressure difference between the inlet and the outlet and the maximum fluid speed of the labyrinth flow paths designed by using these sample points.Based on the data obtained from the simulation,a variety of surrogate models are constructed,and the accuracy of the Kriging(KRG)surrogate model is highest,its decision coefficient values are 0.9388 and 0.9435,and its root mean square error value is also the smallest;Combined with surrogate model technology,the individual sensitivity index and the total sensitivity index of key structural design parameters of the labyrinth flow path in the valve core of the labyrinth control valve were calculated by applying Sobol Global Sensitivity Analysis(GSA)method.The results show that the two structural parameters of flow path width and flow path depth of the labyrinth flow path have the greatest influence on the pressure difference between the inlet and the outlet and the maximum fluid speed of the labyrinth flow path.Finally,the four structural design parameters of the labyrinth flow path were optimized using the multi-objective genetic algorithm NSGA-II based on the previous Kriging surrogate model,and then an acceptable one was selected from the obtained Pareto optimal solution set.According to these parameters,the three-dimensional model of the labyrinth flow path was established,and then the internal flow field was numerically calculated.Compared with the original model,the pressure difference between the inlet and the outlet of the optimized labyrinth flow path structure increased from 3e5 Pa to 1.58e6 Pa.Therefore,the pressure reduction ability of the optimized labyrinth path is greatly improved.