Research On Simulation And Optimization Of BWZ-250 Pump Increasing Foam Pressure Equipment

Along with energy sources and geological sources'requirement increasing, geological drilling environment becomes more complex , in this case ,foam drilling is used extensively ,so foam increasing-pressure technique is promoted to the higher developing level. If the working efficiency of the equipment is boosted ,the increasing-pressure technique will be used in the deeper drilling hole ,and large economic benefit will be created. So it is necessary to study the equipment which is higher increasing-pressure ,smaller suitable dead area,appropriate shape .Foam drilling can be used in the more complex drilling environment .Foam drilling technique level can be improved ,and drilling cost is debased . This is benefit to raise China's foam drilling technique'competition in both domestic and international market.Based on BWZ-250 pump foam increasing-pressure equipment'former research, this thesis puts emphases on simulation and computation of dynamic flow field ,which combines inner flow of the increasing-pressure antrum with piston motion to analyse and show inner flow law. For the purpose of increasing the working efficiency ,the increasing-pressure equipment is changed from several aspects to minish the structural dead space。According to the results of computation fluid dynamics analysis,the optimized design is put forward. Following conclusions and innovations can be concluded from this research of paper:(1) The Finite Volume Method(FVM) is available in computing the inner flow field of BWZ-250 pump foam increasing-pressure equipment relatively exact computing results can acquire by simple supposition and computing mode for this paper .It's known that better precision is guaranteed by using following settings in comparing with the former experimental results: SIMPLE velocity-pressure coupling arithmetic. First order upwind difference discretization; standard k ?εturbulent model;Applying spring-based smoothing to control the piston movement, with specified shear applied for near-wall treatment.(2)By analyzing of entire process for the equipment with impulsion frequency 200r/min,stroke 100mm , the diameter of the piston crock piston cylinder,80mm,conlusion can be draw as follow:1) During stroke process, the piston moves rightward ,and liquid piston will go upwards. Compressed air will be compressed again ,the interface of air and liquid presents protruding curve .2) During return process, the piston moves leftward, and liquid piston will go down .compressed air and liquid will be inhaled in the equipment , ,the interface of air and liquid presents concave curve.3)In stroke process , the velocity of the piston will increase at all times ,but the extent will reduce gradually, and then the velocity will be steady. Liquid piston's movement changing follows the solid piston. The velocity of the interface center is 0.035m/s. The velocity of piston will reduce in return process .When the piston reaches left dead center, the velocity of the interface center is 0.003m/s.The law of the interface center velocity is sinusoid. (3)By analyzing ,the primary structural factors which influence the working efficiency is impulsion frequency, stroke ,the shape .aiming at four factors ,simulation is given.1) Impulsion frequency is designed to be 200r/min,116r/min,72r/min,42r/min, simulation shows impulsion frequency is smaller ,and stability of the liquid piston will be increased. 72r/min is suitable design.2)If stroke is big, liquid piston will go higher, more compressed air will be expelled from increasing-pressure crock. At last, it is suitable that the stroke is 110mm.3) The shape of the crock changes from column to taper, the top is designed to arc. The design is similar with the shape of the interface, which is beneficial to increasing liquid surface's steady.Dynamic mesh and two-phase model are used to simulate equipment'inner flow field, the state of two phases mediator is obtained. There is a great breakthrough comparing to early research, but it still need to be improved, such as model building, mesh meshing and flow field parameter set. In order to simulate impacting system more reasonably, experiment and CFD computing results should be combined to study in simulating more accurately. This thesis analyses the equipment inner flow field in theory. But the results need to be tasted by experiments.