A two-dimensional numerical study of heat transfer in a finned tube assembly during axisymmetric dehumidification

This paper presents the analysis of two-dimensional heat transfer in an ann ular finned tube assembly during the process of dehumidification All possib le fin surface conditions, namely, dry, fully wet, and partially wet, have been studied and fin efficiency under these conditions have been modeled Co mputations have been carried out using a control volume-based finite-differ ence method and compared with past one-dimensional analytical studies and a vailable experimental data. The parameters that influenced the heat transfe r rate in the finned tube structure are ratio of fin and wall thermal condu ctivities, ratio of fin thickness to fin pitch, ratio of wall thickness to fin pitch, ratio of fin length to fin pitch, cold fluid Blot number, ambien t Blot number, the relative humidity and dry bulb temperature of the incomi ng air, and the cold fluid temperature inside the coil. It was found that t he heat transfer increased with increment in both dry bulb temperature and the relative humidity of the air. The fin efficiency changed rapidly with r elative humidity under partially wet condition. The results suggest that co il performance can be very significantly altered by the condensation phenom enon on the fin surface and designs with dry fin data may not be adequate. The present results are expected to be very useful for the design of dehumi difier (cooling) coils for air conditioning applications.