Modeling and optimization of the delivery fluctuation of gear pumps

¹ National Technical University of Athens, School of Mechanical Engineering, Laboratory of Machine Design, 9 Iroon Polytechneiou, 15780 Athens, Greece
² School of Pedagogical and Technological Education, Department of Mechanical Engineering Educators, Iraklio Attikis, 14121 Athens, Greece

^* Corresponding author: etsolakis@central.ntua.gr

Abstract

Presented work aims to minimize the delivery fluctuation of a gear pump through geometrical optimisation of the tooth flank. Therefore, instead of examining various configurations, which would reduce the flow ripple ad hoc, the current study suggests the dependence the delivery fluctuation to the tooth flank profile. Taking into account the secondary derivative of the tooth profile, the optimisation process is able to also affect the secondary delivery fluctuation, which is connected to the compression of the fluid over the meshing cycle. Bezier-Bernstein polynomial curves were used to model the tooth flank in order to satisfy the objective function. A dependency between the total length of the path of contact curve and the flow ripple was found. It is stated in this work that for every design point on a closed path of gear set, there is a threshold on the contact length, over which the resulted flow ripple starts to deviate from the optimum value. That conclusion was used to further enhance the optimisation algorithm. The presented optimum gear profile design was evaluated through a comparative study between every design point and the corresponding solution of the existing state of the art in terms of delivery fluctuation.