Numerical investigation of the effect of swirling flow caused by twisted tape in impinging jet's nozzle on heat transfer: Application in cooling of electronic components and turbine blades

Abstract

BackgroundIn this article, the impinging jets (IJ) with the swirling flow coming out of the nozzle, which is created by twisted tape, were studied. MethodsTwisted tapes (TT) are considered in two models, in the T1 model, one twisted tape is in the center of the nozzle, and the T2 model, four TTs at the edge of the nozzle were placed at the same distance. The results show that this type of IJ creates an asymmetric distribution in heat transfer (HT) on the surface and increases the HT in certain directions when the nozzle is close to the impingement surface compared to normal IJ. At a low Reynolds number (Re), the swirling flow almost reduces the HT. However, when Re increased, the swirling flow's effects on Nusselt number (Nu) became higher, and at relatively close proximity to the impingement surface, it increased the HT in comparison to the comparable normal IJ. The effect of the whirling flow is less and the Nu distribution becomes more symmetrical as the nozzle's distance from the impingement surface increases. Significant findingsThe effect of the swirling flow of the T1 model on HT is greater than that of the T2 model. In the T2 model, a slight decrease in HT was generally observed.