Flow Field Simulation And Structural Design Of Gerotor Pumpwith Arc-Cycloid Profile

Gerotor pump with Arc-Cycloid profile is widely used in lubrication system ofvehicles, marines and other equipments due to its compact structure, smooth operation,low flux pulse and high volume efficiency. Currently, domestic gerotor pumps arebasically developed by imitation or analogy method, theory and development processaren’t adequate for the design of gerotor pump. The former researches about gerotorpump are mainly focus on the design theory, but little attention is paid to thepracticability of research results, so that there are still lots of investigations onimproving the instructive significance for the engineering practice should be carried out.In response to those issues, design methods and theory of gerotor pump werestudied by means of theoretical derivation and simulation, and then experiment wascarried out to verify the correctness of the simulation. Form a perspective of productdesign, the modeling process of internal and external rotors was packed into software,structure parameters and technical performance requirements which were mostconcerned by users of gerotor pump were taken into account in design to ensure thepracticability of research results. Dynamic interference-detection method and numericalprototyping technology were introduced to digitize the design process, which would behelpful to exclude design flaws and errors during design stage so as to improvedone-time success rate of product design. Meanwhile, in order to shorten the productdevelopment cycle, one feasible scheme of flow field simulation was needed forestimating flow field characteristics during design stage, which was used to analyzewhether the design scheme could satisfy the minimum performance requirement.Combining with principle of engagement, differential geometry andhydromechanics，working principle of gerotor pump and forming mechanism ofinternal and external rotors were discussed, and Simulation for internal flow field ofgerotor pump were also developed based on the theory of hydromechanics. Maincontents of this research could be listed as follows:①Basing on the envelope theory, the equations of internal rotor’s profile werededuced, the influence of short-amplitude cycloid profile’s radii of curvature wasinvestigated. The restraint method for avoiding top-cutting of internal rotor’s profilewas discussed; According to geometrical characteristic of gerotor pump, optimizationmethod for fetching best generating coefficient and arc-diameter coefficient were adopted, and then optimal design to the initial development program.②Structure of porting plate played an important impact on gerotor pump’svolumetric efficiency, so that improvement efforts was made to develop a new kind ofseal curve which could help to promote gerotor pump’s volumetric efficiency by fullytaking advantage of oil absorption inertia.③In order to pack the design process of internal and external rotors into softwareprogram, Visual Basic was used during the secondary development to3D modelingsoftware Solidworks, and then virtual assembly and interference analysis technologywere adopted to validate the correctness of rotors’ design, which could provideconvenience for high efficiency product design.④Recur to CFD software Fluent, dynamic mesh technology and user-definedfunctions for moving wall were introduced, and then3D flow field simulation to gerotorpump’s channel model was employed according to k-ε turbulence model. The settingmethods and the rules of key parameters in the application of dynamic mesh technologywere discussed to fetch an available program for performance prediction of gerotorpump during its new product R&D process. Meanwhile, experimental verification wasmade to confirm the simulation results, and then whether the design scheme was able tosatisfy technical performance requirement of gerotor pump could be determined.