| Butterfly cam rotor pump is a new type of rotor pump developed to meet the needs of slurry grinding fluid transportation in pulp industry.Because its rotor adopts a new type of butterfly structure,its hydraulic performance is still unclear.In this paper,The dynamic grid technology,RNG 6)- turbulence model and SIMPLEC algorithm of Fluent software were used to simulate the internal flow field of double-leaf butterfly cam rotor pump,and the numerical simulation results were analyzed.The internal flow principle of the cam rotor pump was obtained,which can provide reference for further research on butterfly cam rotor pump.The main work and achievements of this paper are as follows:(1)Taking the double-leaf butterfly cam rotor as the research object,the dynamic and static coordinate system of the two rotors is established by using the method of bipolar coordinate function,and the profile equation of the double-leaf butterfly cam rotor is obtained according to the engagement theorem of the rotor.(2)According to the drawn rotor profile,the original model of the rotor pump was established.According to the analysis of the numerical simulation results,it can be seen that the local high pressure in the pump is caused by the existence of trapped liquid chamber in the original model of the rotor pump.Local high pressure in the pump causes uneven force on the rotor of the rotor pump,causes vibration and noise of the rotor pump,affects the service life of the rotor pump,increases the torque ripple of the rotor shaft and reduces the efficiency of the motor;the flow ripple at the outlet of the rotor pump causes vibration and noise of the pipeline and its accessories,and damages the pipeline;therefore,with the studying on the rotor profile,inter-rotor clearance,the speed of the butterfly cam rotor pump and the pressure difference between inlet and outlet,which influence the flow fluctuation at the outlet of the rotor pump and the force acting on the rotor,the radial force acting on the rotor and the torque of the rotor shaft are obtained,and the volumetric efficiency of the rotor pump is calculated accordingly.(3)The single variable method was used to study the rotor pump.The results show that with the increase of the radius of the tip corner of the rotor,the pressure of the trapped cavity in the pump decreases,the radial force fluctuation amplitude of the rotor and the torque fluctuation amplitude of the rotor decrease,the volume efficiency of the pump increases first and then decreases,and the fluctuation trend of the two adjacent peaks of the flow fluctuation at the outlet of the pump is opposite.The outlet flow characteristic is the best when the radius of cusp fillet of the rotor of the model pump studied in this paper is 2-3 mm.With the increase of rotor clearance,the pressure of trapped liquid chamber in pump decreases,the amplitude of radial force fluctuation and torque fluctuation of rotor decreases,but the volume efficiency of pump decreases sharply and the operation efficiency of pump decreases.When the demand is satisfied,the smaller clearance value should be selected.With the increase of rotational speed,the pressure of trapped liquid chamber increases,and the amplitude of the flow fluctuation at the outlet of the pump increases.The volume efficiency of the pump increases.With the pressure difference between the inlet and outlet of the pump increasing,the pressure in the trapped chamber increases,the amplitude of the flow fluctuation at the outlet of the pump decreases,and the volume efficiency of the pump decreases.(4)In order to study the wear characteristics of different particles on the internal wall of the rotor pump,Mixture mixed model was used to simulate the whole flow field of the rotor pump.The solid velocity and solid volume fraction contour and velocity vectors of the axial section of the pump at different time were compared and analyzed when the volume fraction of solid medium conveyed was 3% and the particle size was 0.3 mm under the rated working conditions.The local wear strength of the butterfly cam rotor pump is qualitatively studied by Finnie cutting model.The results show that the particles have severe cutting wear on the tip of the rotor,followed by the wall of the pump chamber,while the wall of the suction chamber rotor is mainly attacked by particles.The wear in the inlet pipe is not significant,and there is a certain intensity of local wear on the wall of the outlet pipe.When solid volume fraction is 3%,solid particle size is 0.1 mm,0.2 mm,0.3 mm and 0.4 mm respectively,and solid particle size is 0.3 mm,solid volume fraction is 1%,3%,5% and 10%,respectively,the wear distribution area in the pump does not change significantly with the increase of solid volume fraction and particle size,while the wear strength increases,and the external characteristics of the pump do not change significantly. |
PDF Full Text Request