3D CFD Study of the Effect of Inlet Air Flow Maldistribution on Plate-Fin-Tube Heat Exchanger

Plate fin and tube heat exchanger are used extensively in heating, ventilating, and air conditioning as well as in refrigeration systems. Non uniform inlet air flow distribution has a substantial effect on heat exchanger performance. This study presents the results of three-dimensional (3D) Computational Fluid Dynamics simulations aim to investigate the effect of inlet air flow maldistribution on the thermos hydraulic performance of heat exchanger. Validation of the computation results with experimental data found in the literature has a shown a very good agreement. Different computation test cases with variety of inlet air flow distribution on in line and staggered plate fin and tube heat exchangers were run to systematically analyse their effects on system performance. The CFD results confirmed the importance of the influence of inlet fluid flow non uniformity on heat exchanger efficiency. Results indicate up to 50% improvement or deterioration in the colburn j-factor are found compared to the baseline case of heat exchanger with a uniform inlet air velocity profile. The 3D CFD method employed by this study has great potential for use in, first, assessments of correlations centred on air flow maldistribution and, second, efforts to optimally design the headers of heat exchangers in order to minimise inlet flow maldistribution and maximise overall system performance.