三维波纹板冲击/发散冷却结构流动及换热特性的数值研究

To further enhance the heat transfer potential of impingement cooling, an impingement/effusion cooling system in which the jet plate was designed as a three-dimensional corrugated shape is proposed based on a typical impingement/effusion system. The three-dimensional corrugated plate consists of a superposition of transverse (X) and longitudinal (Y ) sinusoidal wave systems, and the jet holes are arranged at the trough of the sinusoidal waves. The numerical simulation of the impingement/effusion system was conducted by utilizing the Realizable k-ε turbulence model based on the Reynolds time-averaged Navier-Stokes equation. The differences in flow and heat transfer coefficient between the three-dimensional corrugated plate and the flat plate were compared and the effect of wave amplitude (A) was studied. The jet Reynolds number based on the jet hole diameter (Re_d) and dimensionless wave amplitude (A/d), with a parameter range of 300<Re_d<3000 and 0.5<A/d<1.1 were studied respectively. Meanwhile, the hole pitch at the transverse and longitudinal direction and impingement distance are fixed as S/d=10.0, P/d=5.0 and H/d=3.0, respectively. Compared with the experimental results, the Realizable K-ε turbulence model gives accurate predictions for the line-averaged and area-averaged Nusselt numbers (Nu_Ave, Nu). The three-dimensional corrugated plate reduces the momentum loss before the jet impinges on the target (effusion) plate and significantly improves the heat transfer coefficient near the stagnation point. When A/d=0.8, the maximum improvement in the Nu_Ave within 1.5d from the stagnation point is 32.3%. With the increase of A/d, the heat transfer in the stagnation region is enhanced, but the heat transfer outside the stagnation region is unchanged. The improvement of changing A/d on Nu is affected by Re_d, and the improvement of Nu corresponding to the increase of Re_d from 300 to 3000 is reduced from 36.6% to 11.6%. With the increase of Re_d and A/d , the flow coefficient gradually increases and the flow coefficient of the three-dimensional corrugated plate is higher than that of the flat plate, but the improvement is less than 3%.