Innovative approach for longitudinal vortex generator design: Impact on thermal performance

This study conducts a numerical investigation to evaluate the influence of design parameters of the novel inclined delta winglet [NIDW] on heat transfer and friction factor characteristics within the range of Re = 5000-17500. The research aims to examine the impact of parameters associated with geometry and arrangement of NIDW, including attack angles (beta = 30 degrees, 45 degrees, 60 degrees), inclination angles (alpha = 30 degrees, 45 degrees, 60 degrees, 75 degrees), and transverse pitch ratios (P-t = 0.166 and P-t = 0.333). The primary approach encompasses numerical investigation employing visualizations, including Reynolds-averaged vorticity and velocity variations in turbulent flow, the contour maps, showcasing Nusselt number variations, temperature and heat transfer coefficient changes across heated surface, pressure loss variation as well as the depiction of the vortex structure based on the Q-criterion, are all presented to enhance the understanding of data attained by computational study. Visual representations and computational data are utilized to provide a full examination of the thermal performance of NIDW. The numerical findings lead to the conclusion that NIDW with lower inclination angle has a pronounced effect on reducing Darcy friction factor. A substantial increase in TEF values are attained in the range of 6.09 % at Re = 5000; 9.80 % at Re = 17500 for P-t = 0.333 in comparison to reference case of DW. Furthermore, the utmost thermal enhancement factor, TEF = 1.33, is attained with application of NIDW at alpha = 30 degrees, beta = 30 degrees and P-t = 0.166. The findings emphasize the significance of achieving a notable increase in TEF values in comparison to the reference case of DW, thereby highlighting the potential of NIDW to improve the thermal performance of solar air heaters.