Needle Valve Erosion, Deformation Failure Analysis

During gas drilling process, the service environment of needle valve is extremely severe, especially in drilling process of high-pressure oil and gas well. Due to effect of high pressure, the outlet velocity of valve port usually can be up to tens of meters per second; in addition, the fluid medium might contain solid particles and liquid droplets. When the large rock particles blocked by the valve port, the pressure in the front of valve will raise rapidly, fluid media will flow through a small gap between valve plug and valve body at a higher velocity, which leaded to erosion groove at the interface of valve parts and heave loss of metal. All that resulted in deformation and failure of needle valve because of perforation of valve body and structural damage of valve plug, even made the valve failure. Therefore, erosion is the major reasons caused deformation and failure of needle valve. To solve this problem, this paper employed computational fluid dynamics (CFD) methods and took computational fluid mechanics and structural mechanics as theoretical foundation,3D geometric model of a JLK adjustable throttle valve was established by using Design Modeler. Discrete phase model and fluid-solid coupling model and standard k-epsilon turbulence model were adopted to simulate the effects of different phases, inlet velocity, opening degree, particles diameter and concentration to the flow characteristics within needle valve and to erosion in the interface of valve and to deformation characteristics of valve body. This study has a great meaning on theory and in academic value, moreover, it also has a great potential to create greater economic benefits and application prospects.