| With the continuous exploitation of land oil,many land-based oil and gas wells have entered the post-mining,as a result offshore oil exploitation has become increasingly common.More than 40% of the world's oil and gas reserves will be come from the ocean in the future.China has rich offshore oil and gas resources,and developing potential of the resources is great.The demands for offshore oil and gas resources increase year by year in China.As the core component of underwater oil and gas mixed transportation system,the nationalization of underwater multiphase pump becomes more and more pressing.To improve subsea production efficiency,the theoretical study of twin screw multiphase pump's rotor profile is made in this paper.The simulation analysis on the flow field in the pump has been carried out by using CFD technology.An experimental test rig has been set up to study the characteristics of the twin screw multiphase pump in the article.Twin screw multiphase pump is a kind of volume type rotor pump,depending on the volume change caused by the sealed cavity,which is formed by the screw and bushing,to inhale and discharge the fluid.Screw,acting as the core element of the twin screw pump,the profile type determines all the property indexes of the twin screw pump.First of all,the geometry and meshing characteristics of the rotor profile is analyzed in the paper.The composition of the initial profile is analyzed emphatically.The coordinate transformation and enveloping principle are used to deduce the conjugate profile of the initial.The equations of the meshing line for the rotor profile is obtained,and the space meshing characteristics of the rotors has been analyzed.Secondly,based on the equations of the rotor profile,three-dimensional model of the flow field in the pump is established.In this paper,the computational fluid dynamics(CFD)method is used to simulate the three-dimensional transient dynamic simulation of the flow field of a twin-screw pump for the first time.The pressure area and velocity area inside the pump are analyzed with finite element method.The characteristics curve of the pump is drawn.The change rules of the characteristics of the pump under different viscosity are gained.The characteristics of three different profiles is simulated and compared.Thirdly,the twin screw pump experimental test rig has been set up.Transportation of pure liquid and gas-liquid mixed of twin screw pump is completed.The characteristics curve of the pump under different velocity and different void fractions has been drawn.Through compare,the result of pure liquid transportation experiment consistent with the simulation,which proves the correctness of the simulation method.The change rules of the characteristics of the pump under different void fractions are gained through the gas-liquid mixed transportation experiment.Finally,according to the theory analysis,simulation and experiment,the final results are elucidated. |
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