Simulation Study for the Effect of Oil Viscosity on Performance of Full Metal Single Screw Pump

摘要

The oil viscosity affects the pump filling coefficient, so it is the important parameter affecting lifting performance of metal screw pump. Firstly using the finite volume method to establish a full-metal single screw pump 3D model, secondly using FLUENT software to calculate outlet pressure changes with different series of oil viscosity in condition of the same inlet pressure.Lastly Drawing outlet pressure change curves to evaluate the concrete effect of oil viscosity on the performance of the pump . The results indicate that the oil viscosity affects liquid filling coefficient of pump. As the viscosity increases, the outlet pressure of the pump increases, the leakage of the pump output decreases, thereby lifting capacity and volumetric efficiency of the pump improve. The traditional rubber stator is cast one layer rubber that is of double helix surface in the metal enclosure, which can be used together with the metal rotor whose outer surface is plated by hard chrome, while working, the stator can be easily damaged because of the swelling, temperature expansion, and easy to aging of the rubber. As the stator is connected with the tubing, while the stator is damaged and we need to replace a new one, we should disassemble both the poles and string, and it leads to a high cost and the stator can not be used any more, which is apparently a great waste of resource. Besides, that the rubber in the inner surface is hard to clear is also one reason leading to the useless of the stator. Full-metal single screw pump can avoid these shortcomings for its stator and rotor are made of metal materials and they take way of clearance fit. This can ensure the screw pump develops the higher working efficiency in normal operation. However the full-metal single screw pump developed quite late, its theoretical study and basic theory is less and not mature. Viscosity is the important factor that affect volumetric efficiency of the pump , so this paper will use the CFD software to simulate and analyze the effect of the oil viscosity on the pump performance.