Research on enhancing impingement structure heat transfer capability based on secondary impingement

Abstract

Impingement structure, renowned for its compact design and exceptional heat transfer capabilities, finds widespread application in diverse cooling systems. The presence of ribs and the prevailing crossflow conditions exert a significant influence on the flow and heat transfer characteristics of the impingement. This study employs the $k-w\text{SST}$ turbulence model to numerically investigate the performance of a single-nozzle impingement with a ribbed target. Experimental validation, conducted using the steady-state copper block method, ensures the accuracy of the numerical simulations. By delving into the secondary impact phenomenon induced by the ribs, a step rib configuration is proposed to enhance heat transfer. The optimal rib arrangement under varying crossflow conditions is also explored. The findings reveal that step ribs can effectively elevate the $N{u}_{wave}$ and the $N{u}_{pave}$ by 7.67 % and 25.47 %, compared to a smooth target. This improvement underscores that the enhancement in heat transfer performance is not solely attributed to an increased heat transfer area but also benefits from favorable aerodynamic effects. The optimal rib placement varies with different crossflow conditions. Under low crossflow conditions, the most advantageous rib positioning coincides with the region influenced by the crossflow stagnation point. Conversely, at high crossflow conditions, the optimal rib placement is upstream of the impingement jet.