Importance of Three-Dimensional Vehicle Heat Exchanger Modeling

This article demonstrates, via a comprehensive study, the necessity of using a 3D computational fluid dynamics (CFD) approach for heat exchanger (HTX) modeling within underhood vehicle simulation. The results are presented as the difference between 1D and 3D CFD approaches with a focus on auxiliary fluid (e.g., coolant) temperature prediction as a function of primary fluid (e.g., air) inlet conditions. It has been shown that the 1D approach could significantly underpredict auxiliary fluid inlet temperature due to neglecting the spatial distribution of primary fluid velocity magnitude. The resultant difference in the auxiliary fluid flow HTX inlet temperature is presented and discussed as a function of the uniformity index (UI) of the primary fluid flow velocity magnitude. In addition, the 3D HTX model’s importance is demonstrated in an industrial example of full 3D underhood simulation.