Predicting the flow distribution in compact parallel flow heat exchangers

This paper presents a computationally efficient flow network model to predict the flow distribution in compact multi-channel parallel flow heat exchangers. Compact U-type and Z-type heat exchangers with nine parallel channels were used as test case on which the model was validated to within 4-8% in terms of non-dimensional flow distribution ratio. The model was used to perform a sensitivity analysis of flow mal-distribution with changes in operational and geometric boundary conditions. The results show that the tube to header area ratio is an important global parameter for controlling mal-distribution. As the area ratio increases, flow mal-distribution becomes more pronounced and more sensitive to increased Reynolds number and decreased parallel pipe length.