Simulation of a vane cell oil pump

For some time now, regulated vane cell oil pumps have been used when necessary in engines for Mercedes-Benz passenger cars. This new technology requires adjustment to the established simulation methods in order to achieve optimum efficiency and operational reliability.

The kinematics of vane cell pumps is based on a combination of translatory and rotary motion. The challenge for simulations lies in the substantial change in chamber volume in conjunction with a virtually incompressible fluid and complex inflow and outflow geometries. A basic requirement for these simulations is the calculation of an operating point for the pump, consisting of speed and temperature, within a suitable period of time.

The problem is solved by means of systematic modeling in the CATIA CAD system and the semi-automatic creation of control point tables. The simulation is run in JavaScript. Depending on the result of the morphing stage, it may be necessary to conduct remeshing. In addition, a prepared mesh is used in the case of specified angle increments. This procedure ensures high mesh quality during the simulation. The calculation is performed using the segregated flow model and adjusted relaxation parameters. This system allows for rapid modeling, meaning that a new geometry can be calculated within one to two weeks.

Transient flow phenomena are described for an operating point during inflow into the pumping chamber and during the pump’s displacement process. Any cavitation observed can be explained with the aid of the speed and pressure distributions calculated on component surfaces. The calculated pressure pulsation on relevant component surfaces is used as an entry load for kinematics and structural calculations.

This presentation describes the setup of the simulation model for a vane cell pump at a constant speed and the results of the first calculations. It also gives an outlook on further improvements to the method and expansions to the application. The results have been evaluated by means of selected observations and measurements from the test.

Speaker: 
Thomas Fischer
Ulrich Stubbemann
Jan Fischer
Kai Fellmann
Speaker Company: 
Daimler AG
Ground TransportationGround Transportation - Sub-IndustryAutomotive