Simulation Analysis Of Structural Performance Of Screw Drill Bypass Valve

As one of the main components of positive displacement motor,the working performance quality of the bypass valve directly related to the normal work of positive displacement motor.The service life of the bypass valve has great effect on the service life of the positive displacement motor.In the process of drilling operation,it can often appear the phenomenon of bypass valve,such as excessive erosion,piercing-caused leakage,may not close and open properly,all of these can cause bypass valve cannot work normally,great effects on the drilling operation.Take the bypass valve of(?)172 mm positive displacement motor as an example,the flow field characteristics of open and close state of bypass valve were simulated and analyzed by using Fluent software,the erosion resistance of bypass valve is analyzed by using discrete phase model.The main work contents are as follows:(1)on the basis of the research of current situation of the development of positive displacement motor,analysis and summarizes the current situation of research and application of bypass valve,summarizes the main problems,and puts forward the purpose of this study and research program.(2)The structural composition of positive displacement motor and bypass valve were studied,the working mechanics characteristics and the main failure reasons of bypass valve were analyzed.(3)The 3D simulation model of the interior flow field of bypass valve was established,the finite element mesh division of the 3D simulation model was completed in ANSYS software.According to the flow field characteristics of bypass valve,simulation parameters were set up in Fluent software.(4)Given the different drilling fluid flow,the interior flow field characteristics of the bypass valve were simulated and analyzed under different opening and closing conditions.The simulation results show that there is a large pressure and velocity gradient in the internal flow field of valve core of bypass valve.The drilling fluid velocity in the side hole channel of bypass valve is much high.And the bypass valve structure optimization measures are put forward according to the simulation results.(5)The drilling fluid erosion characteristics of bypass valve under different flow and sediment concentration by using discrete phase model.The simulation results show that the most serious erosion wear of bypass valve happen in the full open position.And the erosion wear rate associated with the flow,sediment concentration of drilling fluid.And the bypass valve structure optimization measures are put forward according to the simulation results.Combining with screw drill tool bypass valve samples and actual working condition,the application of CFD software for screw drilling tools by-pass valve opening and closing state of the flow field characteristics is analyzed,and according to the simulation results of screw drill tool bypass valve structure optimization,to better control the performance of the bypass valve work,enhance the working efficiency of the drilling process.At the same time,using the discrete phase model in CFD software,the bypass valve is most serious erosion wear parts for structure improvement,to improve the service life of the bypass valve has certain reference significance.