Numerical Prediction of Laminar Characteristics of Fluid Flow and Heat Transfer in Finned-Tube Heat Exchangers

Abstract

This study is performed to determine the characteristics of fin and tube heat exchanger for the plain and wavy fin configurations considering in lined and staggered tube arrangements for laminar flow regime. This analysis has been conducted using Commercial Computational Fluid Dynamics Code ANSYS CFX-11. The results are expressed in terms of friction factor (f) and the Colburn factor (j) and efficiency index (j/f).The code was validated by comparing the results obtained with the previously investigated experimental data. The effects of different geometrical parameter such as Longitudinal pitch, Transverse Pitch, Fin Pitch, Wavy angle on the heat transfer and the pressure drop were investigated. This study reveals that the flow distinction between plain and wavy fin has a profound influence on the heat transfer and pressure drop performance. It was observed that, increasing the longitudinal and transverse pitch causes a decrease in the thermal and hydraulic performance of the heat exchanger for low Reynolds Number problem. The result for the fin pitch study indicated that decrease in the fin pitch causes a decrease in both heat transfer and friction characteristics significantly.

Keywords: Friction factor, Colburn factor, Efficiency index, longitudinal pitch, transverse pitch, fin pitch.