Study on the mechanism of enhanced heat transfer through punched vortex generators in the frame of convective transport equation of heat flux

In this work, the impact of the perforation technique of vortex generators on both local and overall heat transfer enhancement under laminar flow was examined in the frame of convective transport equation of heat flux. The research findings revealed that the intensity of heat flux transmission along the x-y-z directions was altered by the perforation method, with the z-direction experiencing the most significant influence. In the intermediate region between the two vortex generators and the near wall region, perforation did not alter the heat transfer behavior. At the position across the hole, the heat transfer rate was enhanced first and then inhibited since the fluid velocity changed. However, the increment in fluid velocity at the hole does not always facilitate heat flux transmission. Near the bottom surface, the jet flow achieved heat transfer enhancement by increasing fluid velocity. Conversely, near the top edge of the perforation, the jet flow enhanced heat transfer by augmenting the velocity gradient. Moreover, the jet flow generated by the perforations reduced the contribution of the longitudinal vortices' velocity to heat flux transmission, resulting in a decline in overall heat transfer.