Effect of air-side flow maldistribution on thermal-hydraulic performance of the multi-louvered fin and tube heat exchanger

For the complex mechanical turbulence by micro-louvered fins coupled with the problems of thermal interaction between air side and refrigerant side, the airflow distribution in such a compact fin-tube air-to-refrigerant heat exchanger is perceived as a compound and non-homogeneous behavior, which is always quite difficult to calculate. In this research, based on the finite volume method (FVM), a verified model and methodology for the cross-flow condenser modeling with multi-louvered fin and tube structure is developed, for evaluating the coupling effects on the performance of multi-louvered fin and flat tube heat exchangers under airflow maldistribution. Firstly, a simplified control volume is selected as the calculating domain, and is validated under uniform airflow with 20 groups of experimental data, including root-mean-square (RMS) errors of condenser capacities, outlet refrigerant temperatures and outlet refrigerant pressures of ±5.99%, ±5.65% and ±5.66% respectively. Secondly, four representative airflow patterns in two-dimensional velocity distributions are adopted to characterize the air velocity profiles, and their effect of airflow maldistribution on the consequent heat transfer and pressure drop. The results indicate that airflow maldistribution affects the condensation capacity, refrigerant pressure drop, as well as the theoretical fan power consumption. The maximum capacity reduction and pressure drop increment are 6% and 34 % respectively for these types of airflow maldistribution. This discussion may be attractive for a great potential in designing and sizing an optimum air arrangement for making the flow distribution more uniform in a significant level.