A Hybrid Approach for Full Numerical Simulation of Heat Exchangers

Understanding the details of flow and temperature fields is important in improving the performance of the heat exchangers. The full numerical solution of heat exchangers are computationally prohibitive because the flow and temperature fields must be simultaneously determined in at least two fluids and the solid surfaces separating the two fluids, making full simulation of heat exchangers practically nonexistent. As complicated as the flow is, there are certain characteristics of heat exchangers that if taken advantage of, make the numerical simulation of the heat exchangers more practical. In this paper, the idea of a hybrid approach is proposed, in which the nonlinear momentum equations for one or two channels are solved by using commercially available CFD codes. The velocity field is then inputted into a user-developed code for solving the linear energy equation for the entire heat exchanger. This is an efficient approach which has been successfully used to fully simulate a parallel flow heat exchanger.