Numerical Investigation of Liquid Jet Impingement for Power Electronics Cooling in Electrified Transportation

Thermal management of power electronic modules in electric vehicles is essential for prolonged life and reliability. Overheating of power modules can cause the semiconductor devices to fail or to have reduced functions. Currently, the strategies to cool power modules in electric vehicles include serpentine-style coolant channels, heat spreading over thick baseplates or horizontal flow through fins. However, as advances in semiconductor technology are achieved, more advanced cooling strategies must be employed. Jet impingement is a potential solution due to its improved thermal management performance compared to traditional methods. In this work, simulations are performed to investigate the effect of jet geometry on heat transfer, while maintaining an acceptable pressure drop. Also, a proposed method is investigated for characterizing the temperature distribution of the power module and is compared to the traditional, bulk heating characterization method. The proposed method locally heats different locations on the top side of the DBC (direct bonded copper), instead of heating the entire surface. This localized heating method is tested with the designs under investigation, which study two jet diameter sizes and different nozzle geometries. The orifice geometries include chamfers, straight orifices and both square and circular jets. A Computational Fluid Dynamics (CFD) model is developed to predict the performance of these geometries and an experimental validation is performed from experiments found in the literature. It was found that the traditional method of characterizing jet impingement could lead to inaccurate temperature distributions within the power module.