CFD Analysis of a Centrifugal Pump Controlling a Vehicle Coolant Hydraulic System: a Comparison between MRF and Transient Approaches

Centrifugal pumps are widely used in different thermal fluid systems in automobile industries. Computational fluid dynamics (CFD) analysis of such a thermal fluid system depends on the accurate component modeling of the system components. This paper presents CFD analysis of a centrifugal pump with two different approaches: Transient (moving grid) and the steady state - Multiple Reference Frame (MRF) methods using a commercial CFD solver Simerics MP+®. In addition, flow and pressure drop data obtained using CFD simulations of a vehicle coolant hydraulic system was compared to results from rig test data. The Transient method incorporates the real motion of the pump blades geometry and temporal flow solutions are obtained for instantaneous positions of the blade geometry. In MRF approach, the flow governing equations for the stationary zone are solved in the absolute/inertial reference frame, whereas flow in the moving zone is solved in the relative/non-inertial reference frame. This study presents a comparison of the Transient and MRF CFD simulation results of a standalone centrifugal pump, for a range of points on the pump curve, and the favorable comparison to the standalone pump tests. Having validated the standalone pump, a complete vehicle coolant hydraulic system incorporating the centrifugal pump is numerically investigated using the MRF approach and compared with the test data. The numerical prediction of flow rates and pressure drops across different components of the coolant system shows close proximity with the test data.