A series of experimental tests are performed for the pulsating jet impingement heat transfer by varying the Reynolds number (5000 ≤ Re ≤ 15000), operation frequency (5 Hz ≤ f ≤ 40 Hz) and dimensionless nozzle-to-surface distance (2 ≤ H/d ≤ 10) while fixing the duty cycle as DC = 0.5. The maximum uncertainty in the measurement of Nusselt number is estimated to be about ±7%. Meanwhile, numerical simulations are performed to demonstrate the instantaneous flow field of the pulsating jet impingement. Particular attention is paid to examine the influence of transmission chamber on the pulsating jet impingement heat transfer. The results show that by using an additional transmission chamber, the pulsating jet impingement heat transfer is enhanced. For example, the circumferentially-averaged Nusselt number around the stagnation point (x/d ≤ 2) is increased up 8%~16% by the adding of a transmission chamber in related to the baseline case under Re = 10000 and H/d = 6. Due to the presence of transmission chamber, the exiting jet velocity profile at the orifice outlet is varied. In related to the baseline case, the transmission chamber makes the time-averaged ejecting velocity in the central zone increase but decrease in the edge zone. As the peak velocity in the central zone of orifice outlet is effectively increased by the use of transmission chamber, the jet impinging velocity approaching to the target surface is also strengthened, resulting in a stronger jet impingement in the vicinity of the stagnation point.

中文翻译：

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对流传热在平坦的目标表面上受到附加喷射腔的脉冲射流冲击

一系列的实验性测试通过改变雷诺数（5000≤为脉动射流冲击热传递执行 重新 ≤15000），动作频率（5赫兹≤  ˚F  ≤40赫兹）和无量纲的喷嘴到表面的距离（2≤  ħ /  d≤10），同时将占空比固定为DC = 0.5。估计努塞尔数的最大不确定性约为±7％。同时，进行了数值模拟，以证明脉动射流冲击的瞬时流场。要特别注意检查传输室对脉冲射流冲击传热的影响。结果表明，通过使用附加的传输室，脉冲射流撞击传热得到增强。例如， 在Re  = 10000和H / d的情况下，通过增加与基准情况有关的传输腔，使停滞点（x / d≤2）周围的圆周平均Nusselt数增加8％〜16％。 = 6.由于存在传动腔，因此节流孔出口处的射流速度分布会发生变化。与基线情况有关，传输腔使中心区域中的时间平均喷射速度增加，而边缘区域中的平均速度下降。由于通过使用传输室有效地提高了孔口出口中心区域的峰值速度，因此接近目标表面的射流撞击速度也得到了增强，从而在停滞点附近产生了更强的射流撞击。