Study of heat transfer and flow field of coaxial round and swirl impinging jets on flat and finned plates via experimental and numerical approaches

Impingement jets are a promising cooling technique for achieving uniform and high heat transfer. This study investigates the heat transfer and flow fields of coaxial round and swirl jets on flat and finned impingement plates, both experimentally and numerically. Experimental and numerical studies are carried out under different parameters and states. Coaxial nozzle geometry, the dimensionless nozzle-to-plate distance (H/D = 0.8–3.2), fin length (0, 2, and 6 mm), flow rate ratio (Q*=0.176–0.823) and restricted and unrestricted jet depending on the presence or absence of blocking plate are taken into consideration as parameters and states. The total flow rate is constant at 85 L/min for all cases. The results show that uniform heat transfer on a flat impingement plate can be achieved for specific parameters. The average Nusselt number (Nu) increases with high Q* and low H/D. Moreover, changes in Nu with respect to variations in H/D are more pronounced at higher flow rate ratios. Although the impingement plates with fins increase the heat transfer, they negatively affect the uniformity of heat transfer on impingement plate. The formation and positioning of recirculation zones in the flow field are affected by the impingement plate geometry, fin length, H/D, and blocking plate. This study is important because it presents an innovation considering the combined effects of coaxial impinging jets and finned impingement plates on heat transfer and flow fields. High and uniform heat transfer is possible for certain parameters and states studied. These results can be guided in electronic device cooling and thermal management systems. © 2025 Elsevier Ltd