Heat Transfer Engineering, Vol.36, No.16, 1397-1408, 2015
Numerical Investigation of the Inlet Baffle, Header Geometry, and Triangular Fins Effects on Plate-Fin Heat Exchangers Performance
In this study, the optimal location of baffle in the header of air-to-air plate heat exchangers and the geometry of the header and the effects of triangular fins arrays on the effectiveness were numerically investigated for different flow rates and Reynolds numbers on different models. The main purpose of inlet baffle and geometry changes is to improve the pattern of flow distribution and assist flow uniformity. The investigations show that the optimal location of the inlet baffle with high Reynolds numbers has an insignificant effect on effectiveness, while with Reynolds numbers 250-3000, the effectiveness is affected significantly by baffle location. On the other hand, the reduction in flow gradients by changes in geometry can improve flow distribution. Moreover, investigations show that the increase in fin density (fins/mm) up to a specific value can enhance the effectiveness. In the present study, the Colburn j-factor behavior versus different Reynolds numbers, velocity distributions, pressure drops, and velocity vectors is examined.