Optimal shape of the multi-passage branching system in a single-phase parallel-flow heat exchanger

A numerical simulation is performedto examine the heat andfluidflow characteristics of the branching system in a single-phase parallel-flow heat exchanger (PFHE) andto obtain its optimal shape. The relative importance of the design parameters [injection angle of the working fluid (Θ), inlet shape andlocation (Yc), andheight of the protruding flat tube (Yb)] is determined to decide the optimization sequence. The optimal geometric parameters are obtained as follows: Θ= –21°, Type A, Yc=0 and Yb=0. The heat transfer rate of the optimum model compared to that of the reference model is increased by about 55%. The optimal values of the parameters can be applicable to the Reynolds number ranging from 5000 to 20,000.