Investigation Of Impact Of Non-Uniform Airflow On The Performance Of Parallel Flow Condenser

In recent years, aluminum parallel flow heat exchangers have received much attentionand interest, not just in automotive filed but also in the heating, ventilation, air conditioningand refrigeration （HVAC&R） industry. There is a plain tendency that many conventionaltypes of heat exchangers will be replaced. When parallel-flow condenser was designed, theairflow was always assumed to be uniform. However, that is not the case. In this paper, westudied the impact of non-uniform airflow on parallel flow condenser.Firstly, simulation model for uniform airflow was built with appropriate correlations.The finite volume method （FVM） was adopted to divide the condenser into many segments.Exit parameters were calculated with NTUmethod according to every segment.Simulation results were compared with20groups of test data. The root mean square error（RMS） of heat transfer, condenser outlet refrigerant temperatures and outlet refrigerantpressures are±5.99%、±5.65%and±5.66%respectively.Subsequently, air flow field outside p the condenser was simulated with computationalfluid dynamics （CFD）. Porous model in Fluent was applied to parallel condenser. Viscousresistance factor C1and inertia resistance factor C₂were obtained by fitting the pressuredrop–velocity experimental data.Finally, comparing with other scholar’s study on finned tube heat exchanger, a modelis proposed to evaluate the effect of non-uniform airflow on parallel-flow condenser. Fourtypes of two-dimensional velocity distributions were adopted to study the impact of airmal-distribution and measure the impact of non-uniform airflow in different direction. Thenfor every airflow profile, performances for four types refrigerant mass flow rate weresimulated. It turned out that mal-distribution of airflow affected the heat flow rate,refrigerant pressure drop, as well as the theoretic fan power consumption. The capacitydegradation and pressure drop increment are in connection with the degree ofnon-uniformity of airflow and the refrigerant mass flux. The maximum capacitydegradation was found to be1%for the least refrigerant mass flux, and6%for themaximal.