Performance Evaluation of an Internal Heat Exchanger Used in the Automobile Air Conditioning Systems

The performance of an internal heat exchanger (IHX) is modeled using computational fluid dynamics (CFD). The IHX is used in the automotive Mobile Air Conditioning System. The present work focuses on building a model using CFD to describe the flow, temperature patterns, and heat transfer within the tubes of the IHX. It investigates the variation of mass flow rate at inlet of the tube with respect to the outlet of the IHX. The CFD results offer an acceptable range of agreement with experiment. The temperature of the flow increased as the mass flow rates were increased, as did the turbulence intensity and pressure. The liquid and gas vapor velocity profiles showed larger velocity gradients near the walls of the IHX than at the middle of the tubes where flow was nearly uniform. A correlation function model between parameters with mass flow rate was created. This model can be used and built upon to evaluate a number of different conditions. It is concluded that CFD simulations is useful for providing additional understanding about flow patterns and heat transfer rates for optimizing the efficiency of IHX designs.