Numerical Investigation Of Positive Displacement Rotary Lobe Pump With Twisted Rotors

The lobe pump is non-contact displacement pump with advantages of simple structure, lightweight and being available for transporting wide range viscosity medium. It is widely used insewage treatment, food, mining industry and agriculture. However, the problem of leakage andflow pulsation has hampered the development and application of the lobe pump. Leakage makesthe output flow rate reduced and then makes the lobe pump efficiency reduced. The flowpulsation is the source of pressure pulsation. Pressure pulsation will produce vibration and noiseand impact the performance and stability of the mechanical system. Thereby, reducing the flowpulsation vibration and noise can improve stability and performance of the mechanical system.With the extensive application of the lobe pump, the need of improving lobe pumpperformance is becoming urgent, in order to reduce the pulsation and noise of lobe pump andimprove the mechanical stability of the overall system, the three-dimensional flow fieldcharacteristics are obtained by performing numerical simulation of flow in a lobe pump and thenthe causes of the lobe pump pulsation and influencing factors are analyzed. This paper provides areference for further reducing lobe pump pulsation, noise and improving lobe pumpperformance. The main contents of this paper are as follows:1. The3D modeling software Pro/E was used to build parametric models of lobe pump withvarious rotors. Finally the models for numerical simulation are obtained.2. In order to solve the problem, the spring smoothing and local remeshing algorithm ofdynamic mesh technique is used. The dynamic flow pattern and flow pulsation of lobe pump areinvestigated. Finally, the disadvantages and disadvantages of different CFD software to solve thelobe pump model are discussed.3. By comparing the simulated results of various lobe pump model at different operatingconditions, the impact of the twist angle, lobes number of rotors, structure of the inlet region andoperating conditions on the internal flow characteristics and flow pulsations of lobe pump isdiscussed.4. By comparing the lobe pump efficiency with different transmission medium, the impact ofmedium viscosity on the lobe pump efficiency was revealed. It provides reference for areasonable selection of lobe pump in different operational conditions and improvement of lobepump efficiency.