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燃机内部冷却的目标是采用更小的流量和压力损失实现通道对流传热系数的提高,并利用均匀的冷却减小热应力。本文采用数值模拟手段,研究了局部冲击冷却对带侧向出流的尾缘双流程通道传热和压损的影响。研究表明:动叶尾缘通道由于侧向出流,在页顶出现一个显著的大回流涡,当地传热系数低,易造成叶片局部温度和热应力偏高。通过在U型通道的隔板布置冲击子孔,可以有效地减小通道中分离涡的影响,提高通道末端的传热,并在对通道平均传热系数影响不大的前提下,显著降低通道阻力。使射流与靶面尽量垂直有助于达到最好的冷却效果。
The goal of internal cooling of the gas turbine is to increase the convective heat transfer coefficient of the channel with a smaller flow and pressure loss and reduce the thermal stress with uniform cooling. In this paper, numerical simulation is used to study the effect of local impact cooling on the heat transfer and pressure loss of the double-flow path with trailing edges. The results show that the trailing edge of the rotor blade has a large backflow vortex at the top due to lateral outflow, and the local heat transfer coefficient is low, which easily leads to the high local temperature and thermal stress of the blade. By arranging the impingement sub-holes on the partition of the U-shaped channel, the influence of the separation vortex in the channel can be effectively reduced, the heat transfer at the end of the channel can be increased, and the channel can be significantly reduced with little influence on the average heat transfer coefficient of the channel resistance. As far as possible perpendicular to the jet and the target surface helps to achieve the best cooling effect.