Abstract

Since 2008, advanced Computational Fluid Dynamic (CFD) simulations have been run in R&D department of Pierburg Pump Technologies, using a transient 3-D simulation analysis performed with PumpLinx Simerics software, in order to investigate the fluid-dynamic field inside the pump and the behaviour of the fluid. Starting from 2011, in PPT the CFD simulations are also used to predict detailed performance of the pump reproducing the phenomenon of waves reflection and pressure fluctuation. By way of example, in this article, we will show the results obtained for a pump of 20cc/rev installed on a diesel engine of 2000cc.
To run this type of simulation, is necessary to evaluate and fix a set of criteria:
-Multiphase fluid: oil, air and vapor;
-Percentage of aeration level;
-Evaluation of Courant number and speed of sound;
-Boundary condition: calculation and sensitivity analysis;
-Mesh grid sensitivity analysis;
-Sample frequency;
-Close cavity with rigid walls.
The comparison between calculation and tests demonstrates that numerical prediction are in good agreement with experimental data. This allow us to optimize the positioning of pressure sensors and accelerometers, integrating experimental tests and CFD analysis.
The advantages of this method are a clear description of the fluid-dynamic field throughout the fluid domain of the pump and just for its high accuracy and reliance, provide the input data for potential subsequent acoustic/vibrational analysis and investigation. The disadvantages are basically two: the possibility of analyzing the effect of a single variable at a time and the high computational cost also with powerful computational resources that means weighting the use of this powerful simulation method only in cases of particular interest or need.