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摘要:
为通过主动端壁控制技术减弱轮缘密封流对主流通道的影响,基于轮毂端壁静压对高压涡轮动叶端壁非轴对称端壁造型,分析了转静间隙密封流与主流相互作用及端壁造型后损失减弱的效果。结果表明:非轴对称端壁造型后密封流对主流通道的堵塞减弱,主流质量流量增加,合理控制端壁造型幅值能够提升涡轮级工作效率;靠近动叶前缘向上凸起的端壁造型增加了轮缘密封腔出口位置的径向压力梯度,增大了燃气入侵与密封出流的强度;主动端壁控制技术降低了主流通道内的横向压力梯度和轮毂二次流结构径向位置,减弱了由密封流引起的二次流损失;密封流质量流量比为1.2%时,造型幅值为5%和8%模型二次流动能分别减少了1.18%和3.76%。
Abstract:To investigate the effect of active endwall control on reducing the influence of rim seal flow on the mainstream passage, this study analyzed the aerodynamic losses of the interaction between the purge flow and the main flow, and the effect of the endwall profiling on the losses reduction, based on the non-axisymmetric endwall profiled by hub static pressure. The results showed that the non-axisymmetric endwall profiling reduces the blockage of the main flow passage by the purge flow, and increases the mass flow rate. The efficiency of the turbine can be increased with a reasonable control of the endwall profiling amplitude. The convex end wall profiling near the leading edge of the blade increases the radial pressure gradient at the exit of the rim seal cavity, and increases the intensity of gas ingestion and purge flow injection. The non-axisymmetric hub endwall profiling reduces the transverse pressure gradient in the main flow passage, lowers the radial position of the hub secondary flow structure and reduces the secondary flow losses caused by the purge flow. The secondary flow kinetic energy is reduced by 1.18% and 3.76% for models with modelling amplitudes of 5% and 8% respectively at the purge flow ratio of 1.2%.
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Key words:
- non-axisymmetric endwall /
- rim seal /
- gas ingestion /
- sealing effectiveness /
- end zone flow
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表 1 第1级涡轮效率
Table 1. 1-stage turbine efficiency
计算模型 效率/% 质量流量/(kg·s−1) original EW 90.0092 11.4605 baseline EW, MIR=0.8% 89.6876 11.3727 baseline EW, MIR=1.2% 89.6294 11.3345 baseline EW, MIR=1.6% 89.5801 11.2893 Nonaxi EW 5%, MIR=0.8% 89.6973 11.4271 Nonaxi EW 5%, MIR=1.2% 89.6551 11.3955 Nonaxi EW 5%, MIR=1.6% 89.7288 11.3593 Nonaxi EW 8%, MIR=0.8% 89.2407 11.4333 Nonaxi EW 8%, MIR=1.2% 89.2816 11.3973 Nonaxi EW 8%, MIR=1.6% 89.4151 11.3612 -
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