Rotational speed is one of the important parameters that impact lifting capacity of full-metal single 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 rotational speed value of the pump in condition of the same inlet pressure .Lastly drawing outlet pressure change curves to evaluate the concrete effect of rotational speed on the performance of the pump. The results indicate that the lifting capacity of the pump and pressure bearing capacity of single stage increase with the rotational speed increasing. The centrifugal performance of the full metal single screw pump is more obvious. So it needs to give full consideration to the effect of rotational speed on characteristics of screw pump in the process of screw pump designing and using, especially the selection of pump series and rotational speed .Increasing the rotational speed of the screw pump can not only reduce the pump series and the structural size, but also can reduce the load torque, improve the reliability of drive system.Now,most of 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[1]. 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[2]. Rotational speed is the main parameter in the designing and using of full metal screw pump ,so in order to help improve the screw pump performance and for further study of the basic theory of metal screw pump, this paper will focus on the study of effect of rotational speed on the pump performance .
