Flow irregularity and wear optimization in epitrochoidal gerotor pumps

The Gerotor pumps have a vast number of applications in industries and automobiles. The flow rate irregularity and wear rate proportional factor influence on the lifetime of the Gerotor pumps. In this paper, the optimization problem cost functions and constraints have been developed according to volumetric, dynamic and geometric properties. In order to have general optimum solution and reduce number of design variables, all variables have changed to non-dimensional variables by using the outer rotor lobe center radius which causes the non-dimensional cost functions too. The multi-objective optimization problem has been changed to single objective optimization problem by using a multi-objective optimization classical method. The single objective optimization problem has been solved by using of a mixed integer nonlinear optimization algorithm. The optimization programming has been implemented for several values of number of the outer rotor teeth, non-dimensional displacement and rotors width. On the other hand the influence of varied parameter such as number of outer rotors teeth, the value of non-dimensional displacement and non-dimensional rotor width have been surveyed on each of cost functions. The results show in constant input torque, as using greater number of outer rotor teeth up to critical value improves the wear of teeth. Also optimum value of flow rate irregularity in odd values of outer rotor teeth is smaller than even ones. At last for having better comparison, two sample commercial pumps have been optimized. The results show both wear rate proportional factor and flow irregularity have been significantly improved.

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