Research On The Cavitation Erosion Of Throttle Nozzle In Well Testing

The throttle valve is the key equipment for controlling and regulating throttle flow and well pressure in well testing and production processes.Due to its good sealing performance,strong over-current capability,fast response,and strong anti-pollution ability,it has been widely used.When the oil passes through the valve port position,the speed is redistributed and the vortex is easily generated.With the fluid medium changing from liquid phase to gas phase,the cavitation phenomenon occurs.With the expansion of the flow area at the rear of the throttle,the velocity of the fluid decreases and the gas-phase bubbles collapse successively due to the pressure rising.When the collapse occurs near the taper valve spool and the surface of the valve body?the high pressure generated by the continuously collapsed vacuole in the water stream repeatedly acts on the spool and the valve body surface,resulting in causing damage to the surface of the spool and the valve body,and is often accompanied by vibration,noise,and performance degradation,affecting the normal operation and service life of the valve.Due to the accuracy of the calculation results depends on the accuracy of the calculation model in the cavitation flow simulation calculation,this paper first validates and corrects the calculation model,and compares it with experimental data to verify its accuracy in cavitation flow simulation.Then,the cavitation flow law inside the conical throttle nozzle was studied using a validated calculation model and method.At the same time,a quantitative prediction model of cavitation damage was proposed.Finally,on the basis of the above research,a conical throttle nozzle was proposed.The results show that the cavitation flow is calculated using the RNG k-e turbulence model,the Schnerr-Sauer(SS)model,and the enhanced wall function model The simulation results are in good agreement with the experimental data.The calculation converges faster and the flow is provided.The field information is more detailed;the detailed cavitation flow field characteristics and pressure,velocity,flow lines,cavitation area,etc.in the throttle nozzle were accurately simulated using the modified cavitation model;based on the wall shear stress mechanism,the cavitation damage quantitative prediction model was put forward and the position of the cavitation risk point of the throttle nozzle was accurately located.The new structure of the throttle nozzle was put forward,and the optimized structure was verified to have excellent performance in suppressing cavitation.