Model based design and numerical analysis of a downsized centrifugal pump for engine cooling applications

The water pump is the crucial component of the engine cooling system. It is usually designed using a roughly methodology based on the maximum power of the engine, and this results in an overdesign of the pump itself, if the real operating points during a driving mission is considered. An improper design can cause the engine to overheat or operate below optimal temperatures, or it can stress too much the control devices, negatively impact engine efficiency. Hence, designing an effective water pump is essential. In this work, a model based procedure to design the pump in a proper engine working point is considered. The procedure starts with an estimation of the engine thermal needs in different working conditions and on a driving cycle. Hence, a flow rate can be targeted, and a pressure drop of the cooling circuit estimated, in order to have the specifics of the design of the pump. The model is able to evaluate all the hydraulic losses of the pump in its impeller and volute. The geometry generated has been refined and finally investigated through numerical CFD analysis. Subsequently, the turbulent flow field of the pump was analyzed in terms of static pressure, velocity, and kinetic energy distribution. The pump head and flow rate delivered were simulated using CFD techniques and compared with experimental results, assessing also the efficiency of the pump and the loss distribution. Finally, the pump performance has been evaluated along a driving cycle, in order to assess the energy absorbed during a real operating condition.