关键词: 流场结构；反压；抽吸；流量系数；深宽比

Abstract: In order to study the effects of the bleed chamber pressure on the flow field structure in the bleed slots， experiments were carried out in a continuous supersonic wind tunnel of National University of Defense Technology. The flow field structure in the bleed slots at different chamber pressure was obtained and diagnosed by non-touched measurement， including NPLS and schlieren. The bleed mass flow rate was measured and the bleed performance was analyzed. The NPLS results and schlieren results clearly show the local flow field structure near the bleed slot， including a series of typical flow field structure， such as the separation bubble， shear layer， expansion wave， barrier shock and shock train. The results show that shock train appears in the bleed slot when pressure ratio increased to 0.25. With the increase of bleed chamber pressure， the expansion angle of the gas flow decreases and the length of the lower half of barrier shock gradually becomes shorter and moves to the downstream， and sonic mass flow coefficient decreases with the increase of bleed chamber pressure. Shock train disappears when pressure ratio increased to 0.6. When chamber pressure is around 0.18， the separation in the bleed slot varied from open state to closed state with the increase of length-to-width ratio. At the same time， the expansion angle of the gas flow increases， the barrier shock gradually moves to the upstream， and sonic mass flow coefficient increases.When the length-to-width ratio of the bleed slot is larger than 1， the separation bubble in the bleed chamber is closed at low chamber pressure， and it is open at high chamber pressure.

Key words: Flow field structure；Chamber pressure；Bleed；Mass flow coefficient；Length-to-width ratio