In this tutorial, we will simulate a gear pump that drives a flow of water. This tutorial makes use of the Immersed Solids capability of ANSYS CFX in order to model a solid that moves through a fluid. For more details see CFX Tutorial chapter 27.

gear pump

Details of Gear Pump Model with inner and outer Rotor

 

The outlet has an average relative static pressure of 7000 Pa; the relative total pressure at the inlet is 0 Pa. The inner rotor (gear) rotates at a rate of 7 rev/s; the outer rotor rotates at 6 rev/s. The diameter of the fluid region between the rotors is approximately 7.3 cm.

An immersed solid domain is used to model the inner rotor, a rotating fluid domain to model the water immediately surrounding the inner rotor, and a stationary fluid domain to model the water in the inlet and outlet channels. To model the stationary pump housing (not shown in the figure), a counter-rotating wall condition is applied to the top (high Z) surface of the rotating fluid domain, on the non-overlap portion (which lies between the inlet and outlet channels). To model the upper surfaces of the teeth of the outer rotor, a rotating wall condition is applied on the non-overlap portions of the lower (low Z) surfaces of the inlet and outlet chambers.

 

Video 1: Video Animation of rotating Gear Pump