Numerical study on heat transfer by swirling impinging jets issuing from a screw-thread nozzle

摘要

To achieve uniform cooling at high heat transfer rates, a novel swirler with some circumferential screw grooves was developed to generate the swirling impinging jet (SIJ). Using the RNG k-ε turbulence model, the behavior of the flow field for the impinging jet in a confined cavity was analyzed, and the effects of jet spacing, swirl angle, and Reynolds number (Re) on the target wall heat transfer characteristics of the SIJ issuing from the screw-thread nozzle were studied. The numerical results showed that the designed swirler was effective to increase the radial uniformity of heat transfer compared to a multi-channel conventional impinging jet. A good result in terms of radial uniformity of local Nusselt number (Nu) was achieved in the case of θ = 60° and a suitable Re in the turbulent status for a small jet spacing of h/d_j ≤ 3.0.