In this paper a two-dimensional numerical model for a minichannel evaporator is implemented. This model takes into account the variation of wall (fin and tube) temperature and moist air properties (temperature and humidity ratio) in both longitudinal and transverse directions. The validation of the current model is done with a well-defined analytical case, the results of both cases show a very good agreement and consistency. A case study from literature has been chosen to compare between the current model results, and the results from traditional ε-NTU method with adiabatic fin-tip assumption which used generally by many authors for modeling and analyzing the evaporator performance. The tube wall temperature is varied from 1.4 °C to 17 °C, under constant inlet air temperature and humidity ratio. These conditions allow different scenarios for the tube and fin (totally wet, totally dry, or partially wet). Deviations in results between the current model and the traditional ε-NTU approach are noticed, especially under partially wet fin condition. These deviations are mainly due to the assumptions which normally adopted by the ε-NTU method and fin theory such as; no variation in moist air temperature and humidity ratio along the direction between tubes, the whole segment (tube and fin) is usually assumed to be either completely dry or wet and no accounting for partially wet scenario.
展开▼
