关键词: 叶尖间隙控制;横流;冲击;强化传热

Abstract: To investigate the heat transfer characteristics of the jet impact casing surface in the external multi-row cooling air pipe structure with initial corss flow， for blade tip clearance control systems based on casing thermal deformation control, the experimental study research was conducted to investigates the effects of initial cross flow Reynolds number (0~8×10⁴) on the heat transfer characteristics of the jet impact casing surface in the external multi-row cooling air pipe structure. It is found that compared with the cross flow Reynolds number, the impinging jet Reynolds number has greater influence on the average heat transfer coefficient at the targets, and the average heat transfer coefficient increases significantly with increasing the impinging Reynolds number. With the introduction of initial cross flow, the impingement stagnation zone exhibits an offset along the initial transverse flow, which weaken the targets’ heat transfer effect and the peak of the local heat transfer number decreases firstly and then increases. The study shows that when the cross flow Reynolds number is larger than 4×10⁴, a ‘fish-tailed’ heat transfer enhancement zone can be observed downstream of the stagnation zone. The cover region of the tail area increases gradually with increasing the cross flow Reynolds number, and the target surface heat transfer effect is improved. The smaller the impingement hole spacing, the higher the local and average heat transfer coefficient at the target surface, and the influence of the cross flow is relatively small. In this paper, the heat transfer effect will be better if the ratio of impingement hole spacing is 4.

Key words: Tip clearance control;Cross flow;Impingement;Heat transfer enhancement