Computational Modeling of Twin Screw Pumps for Thermal Management Applications

Electrification has become less of a catchphrase and increasingly commonplace when discussing today’s locomotives. Engineers developing thermal management strategies (both component suppliers and system-level analysts) must be armed with effective tools to design and analyze essential components such as coolant pumps and study their behavior in an actual system.

 

This study focuses on the analysis of twin screw pumps for cooling battery packs in hybrid and battery electric vehicles via three different approaches—experimental measurements, a one-dimensional (1D) thermodynamic chamber model, and a three-dimensional (3D) computational fluid dynamics (CFD) model. Experimental measurements are conducted to quantify the coolant’s volume flow rate and estimate hydraulic power consumption over a range of operating speeds and pump discharge pressures. While these measurements provide some insight into the overall internal leakages and pumping efficiencies, more comprehensive tests at a higher cost are required to fully understand the detailed thermodynamic processes occurring within the pump. Two computational modeling approaches are presented and extensively validated against these measurements. The 1D chamber model demonstrates a good agreement of all measured quantities at a very low computational cost. It also provides useful information regarding the relative importance of the various leakage paths along with the working processes and pressure pulsations. This makes it an effective tool to quickly analyze operating conditions where test data may not be available and iterate toward improved designs via parametric analysis. A 3D CFD yields very good agreement compared to the measured results and provides a more complete picture with greater spatial accuracy that is sacrificed in the 1D approach. However, this is available at a significantly higher computational cost. A combination of both methodologies can guide engineers in designing screw pumps for optimal performance.

 

In this study SCORG was used as geometry calculation preprocessing tool. The SCORG mesher provides pre-generated rotor grids which are then used by the CFD solver during run time for mesh deformation calculations.