Dynamic Characteristics Research Of Control Ring Seal Based On Dynamic Mesh And Calculation Of Wet Critical Speed Of Rotor System

With the development of the industry, Rotor system develop towards high speed, high power, Traditional rotating machinery have been unable to meet the demand of the quickening productivity; However, increasing speed will bring a series of problems, such as, affecting the stability of rotor system, leading to vibration of the rotor system, etc, And vibration will affect the efficiency of the equipment, even lead to damage of equipment. Because of there are many small annular clearance in multistage centrifugal pump and its complex structure, fluid in clearance will lead the exciting force on the rotor, and to change the dynamic characteristics of the rotor. In this paper, a ten- stage centrifugal pump was regarded as the research object. Calculating pressure field and velocity field of cylindrical and conical seal in computational fluid dynamics software FLUENT; Analyzing The change of spillage along with differential pressure in cylindrical and conical seal, Comparing sealing performance of the two seals. Analyzing the influence of eccentric, differential pressure, axial sealing length and rotating speed of the rotor on the sealing performance; Calculating the dynamic coefficients of the front seal and back seal of multiple-stage centrifugal pump with moving reference frame, and calculating the dynamic coefficients of conical ring seal who has the same geometry size and hydraulic diameter with the front seal. Comparing the dynamic coefficients of cylindrical seal and conical seal;Proposing a new method of calculating the dynamic characteristics of damping coefficients which is based on dynamic grid technology. Using dynamic grid method to calculate the rotor dynamic characteristics of the cylindrical ring seal and comparing the results with that of Lindsey’s experiment and moving reference frame, verifying the exactness of the moving grid method;Compiling the program of calculating the critical speed of rotating rotor system in Matlab.Calculating the critical speed of rotor system with the control ring seal and conical ring seal, comparing and analyzing the results. Verifying the correctness of the Matlab program in ANSYS, comparing the calculation results of the two methods.Comparing the critical speed of considering seal support and not considering seal support, and analyzing the influence of fluid in seal clearance on rotor dynamic characteristics of multistage centrifugal pump.The results show that, for the cylindrical and conical ring seal with the same geometric parameters and hydraulic diameter, Conical sealing ’s performance is better than that of the cylinder control ring seal, stiffness of conical sealing ring is bigger, the critical speed of rotor system with conical ring seal is greater than that with cylindrical ring seal, rotor system with conical ring seal is more stable and smaller possibility to violent vibration; Rotor system ’s "dry" and "wet" critical speed is very different, the influence of fluid in clearance on the rotor dynamic characteristics should not be ignored...