Multi Parameter Erosion Analysis Of Underwater Throttle Valve

The underwater throttle valve is an indispensable part of underwater Christmas tree.It plays the role of adjusting the output speed and controlling the flow of production units,and can control the start-up and shut-down of oil and gas wells.The working environment of the throttle valve is very poor,and it is under high pressure during operation.The liquid carrying sand particles flowing at high speed will cause erosion to the throttle valve.The primary reason for the failure of the throttle valve is erosion.Based on the theories of erosion and computational fluid dynamics,this thesis establishes the fluid region models of throttle valves with different structures.Considering various erosion related theories,the numerical model most suitable for the erosion simulation of throttle valve is selected.According to the calculation results,the specific erosion values and erosion characteristics of throttle valve body are obtained.For the three kinds of parameters affecting the erosion of throttle valve,namely opening degree,flow parameters and structural parameters,the research work is mainly carried out from the following aspects:(1)Create a throttle fluid area model and mesh it.According to the governing equations of computational fluid dynamics and discrete phase governing equations,the standard k-epsilon turbulence model is adopted in Fluent,and the flow field distribution characteristics and erosion characteristics in the throttle valve are obtained through simulation calculation.On this basis,a comprehensive analysis is carried out.(2)20 throttle valve models with different opening degrees are created for calculation respectively,so as to explore the characteristics of the flow field distribution of the throttle valve and the change of erosion results due to the opening degree.Finally,the characteristics that the pressure,velocity,average erosion rate and maximum erosion rate of the fluid at each position in the valve body are affected by the opening are obtained.Thus,the suitable opening range of throttle valve in practical operation is put forward.(3)The influence of fluid flow parameters on the erosion of throttle valve is studied by using the control variable method.The three flow parameters of fluid velocity,liquid sand content and sand particle diameter are studied respectively.Each flow parameter is compared with five groups of erosion simulation,and finally the flow parameters and actual working conditions that are most suitable for the operation of underwater throttle valve are obtained.(4)The models of 14 throttle valves with different structures are re-established to explore the influence of the structural parameters of the throttle valve on the flow field distribution and erosion of the valve body.The diameter of the inlet pipe section,the diameter of the outlet pipe section,the number of orifices and the angle between the orifices and the horizontal plane are four structural parameters,and each structural parameter is compared with four or five groups of erosion simulation.Based on this,the optimization suggestions of throttle valve design are put forward.