Enhancement of thermal and hydraulic performance of compact finned-tube heat exchanger using vortex generators (VGs): A parametric study

Abstract

In this study, a numerical analysis is conducted to investigate the influence of interrupted surfaces on compact heat exchangers (CHXs). The performance of CHXs in terms of heat transfer enhancement and pressure drop can be augmented by incorporating innovative passive techniques. In relation to that the influence of delta winglet vortex generators (DWVGs) on thermal-hydraulic features of heat exchanger is elucidated. The effect of vortex generators (VGs) with different number of rows (N), attack angles (θ) and configuration on heat transfer performance (j) and pressure drop (f) are demonstrated. Moreover, the influence of tube arrangements such as inline and staggered placement of tubes and different tube shape (circular, oval and rectangular) are also deduced. The optimum attack angle (θop) of VGs is concluded i.e. 1650, which provides higher transfer performance at moderate pressured drop (ΔP). Array of winglet rows gives comparatively higher heat transfer rate than one row of winglets and also common flow down (CFD) configuration of winglets are preferable over common flow up (CFU) configuration of winglets. Moreover, staggered tubes arrangement tends to provide relatively better thermodynamic features as compared to inline arrangement of tubes. Finally, it is concluded that oval and circular tubes deliver quite comparative act in terms of thermal and hydraulic performance as compared to rectangular tubes.