Optimization Design And Simulation Of A Tri-polar Parallel Compound Gear Pump

With the development of hydraulic transmission technology and pumps, the research and manufacture of new type gear pumps are increasingly important. As a new type of structure of gear pump, when compared with ordinary gear pump, the tri-polar parallel compound gear pump has better instantaneous flow and radial force characteristics, when compared with other new type of structure of gear pump, it has more simple structure and better manufacturability. So the tri-polar parallel compound gear pump has broad prospects of engineering application.Based on the instantaneous flow formula of ordinary gear pump and variation of meshing points displacements, the instantaneous flow of the tri-polar parallel compound gear pump has been researched, and the flow formula is derived. Under two conditions of the tooth number of driving gear is and isn't multiple of 3, the instantaneous flow characteristics is researched, and the wave curves are created by MATLAB. Then it is concluded that under the condition of the tooth number of driving gear isn't a multiple of 3, the tri-polar parallel compound gear pump has better instantaneous flow characteristics. Radial forces of gears are analyzed, it is concluded that the resultant radial forces of driving gears is zero, and the tri-polar parallel compound gear pump has good radial force characteristics.The optimization design of gear parameters of the tri-polar parallel compound gear pump is proceeded by taking the minimum volume of the pump body as the objective function. In the process of establishing objective function, the volume of pump body is described by using the mounting holes volume of addendum circle on the pump body. This description can more accurately reflect the volume of the pump body compared with others. A new three-dimensional step-by-step search algorithm is adopted to solve mathematical model of the optimization design by using MATLAB. Then the optimization result of gear parameters is obtained. A workable and effectual method for the optimization design of the tri-polar parallel compound gear pump by the objective function and the new three-dimensional step-by-step search algorithm, and it can be used for reference to the optimization design of ordinary gear pump.Based on the optimization result of gear parameters, the physical model of the tri-polar parallel compound gear pump is established. Then the flow field simulation of its 2-d simplified model is proceeded by using moving-grid technology of Fluent. This study has laid a foundation for further research about the flow field simulation of 3-d model of the tri-polar parallel compound gear pump and the ordinary gear pump.