Numerical Analysis of Geometry Influence on Heat Transfer in a Slotted Fin and Tube Heat Exchanger

Abstract

The influence of geometric characteristics on thermal and hydraulic performance of slotted fin and tube heat exchangers has been numerically analyzed. Numerical model of a slotted fin and tube heat exchanger has been developed and validated using the experimental data. Considered geometric parameters were fin pitch, fin thickness, and slots height. Air inlet velocities ranged from 1 to 4 m/s, corresponding to Reynolds numbers ranging from 558 to 2234. Total of 56 different cases have been numerically solved and results have been presented in terms of exchanged heat flux, average air outlet temperature, and pressure drop along the heat exchanger. The analysis showed that for the considered operating conditions, an increase in fin pitch results in a slightly higher exchanged heat flux and significant reduction of pressure drop, but after certain value further increase in fin pitch does not result in a noticeable augmentation of exchanged heat flux. Additionally, higher exchanged heat flux was achieved for greater fin thicknesses but causing higher air-side pressure drop. Finally, it was found that the slots height for which a heat exchanger will achieve the highest exchanged heat flux depends on air inlet velocity, however the pressure drop was lower in cases of smaller slots heights.