Turbocharger Heat Transfer Modeling Under Steady and Transient Conditions

Abstract

In the field of automotive propulsion, environmental issues (need for drastic reduction of greenhouse gases) and diminishing fossil fuels supplies enhance the need to reduce fuel consumption. To reach this goal, a possible solution is downsizing. Unfortunately, the degradation of the transient performance of the engine limits the expected benefits of downsizing. Engine manufacturers try to improve turbocharger matching using simulation. However, the literature and experiments on a turbocharger test bench show that, contrary to general opinions, heat transfer can influence the turbocharger performance. Thus it seems essential to determine and correlate the different types of heat transfer phenomena occurring in a turbocharger. First a complete experimental characterization of turbocharger heat transfer is performed in steady and transient conditions. The experimental results are used to correlate turbocharger heat transfer coefficients. Then, the equivalent heat transfer resistance method is explained. The correlations obtained are then used in this method to calculate all heat transfer interactions within the turbocharger and transferred to the surroundings in steady and transient conditions. In each case, comparisons between numerical and experimental results are performed to verify the quality of the method proposed.