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Airflow maldistribution in heat exchangers and air channels is a common problem in HVAC&R systems. Furthermore, in the refrigeration field, temperature and velocity maldistribution downstream the evaporator can reach the discharge air grille, negatively influencing the heat removal from the exposed goods. In the present paper, the effect of the flow maldistribution in the air channel of an open refrigerated display cabinet is studied by means of computational fluid dynamics simulations. An equivalent thermal approach is presented: in combination with the equivalent resistance approach, it allows a drastic reduction of computational effort. This thermal CFD model allows to evaluate the 3D effects of the maldistribution in terms of temperature, heat transfer coefficients, and cooling power in the full channel model. Discussion of the results is reported. [ABSTRACT FROM AUTHOR]

The combined heat and mass transfer mechanisms owing to the temperature and humidity ratio differences and their influence on the efficiency of different exponential type porous fin configurations are analyzed in this paper. The closed-form temperature solutions for an exponential impermeable dry fin as obtained in an earlier publication (Turkyilmazoglu, 2012) are extended here to the case where the surface of the fin is fully wet and porous. A comparison with the traditional straight porous fins proves that the fin tip temperature and efficiency of the exponential porous wet fins are much better than those of corresponding to the straight porous wet fins. [ABSTRACT FROM AUTHOR]