等压差条件下多斜孔综合冷效实验研究

Experimental Study on Overall Cooling Effectiveness ofInclined Multihole under the Same Pressure Differential

关键词:  航空发动机  压差  多斜孔  气膜冷却  综合冷效

Key words:  Aero engine  Pressure differential  Inclined multi-hole  Film cooling  Overall cooling effectiveness

摘要:

为了研究不同进气条件对多斜孔气膜冷却的影响规律，采用实验方法，从等压差和等冷气量两个角度分别探讨了孔径d为0.5mm~1mm，开孔率op为0.0245~0.0383，流向倾角α为20°~45°的变化对综合冷效的影响规律。实验结果表明：综合冷效沿流向方向逐渐增大。开孔率和流向倾角不变时，孔径减小，在等单位面积冷气量下，综合冷效显著增加；在等压差条件下，孔径越小，单位面积冷气量越小，综合冷效仍然随之增加。孔径和流向倾角不变，两种进气条件下，综合冷效随开孔率的增加而增加，但等压差条件下增大幅度更高。孔径和开孔率不变，在等冷气量条件下，20°流向倾角综合冷效最高；在等压差条件下，30°流向倾角综合冷效最高。

Abstract:

In order to study the effects of different inlet conditions on film cooling with multihole, the variation of the hole diameter (0.5mm~1mm),the open porosity (0.0245~0.0383) and the inclined angle of the flow (20°~45°) on the overall cooling effectiveness were discussed experimentally from two perspectives of the same pressure differential and the same coolant flow rate. The experimental results show that the overall cooling effectiveness increases along the direction of flow. As the open porosity and flow direction inclination remain unchanged, the overall cooling effectiveness increases significantly with the decrease of hole diameter under the condition of the same coolant flow rate. Under the condition of the same pressure differential, the smaller the hole diameter, the smaller the coolant flow rate is, the overall cooling effectiveness is still increasing. As the hole diameter and the inclined angle are constant, the overall cooling effectiveness increases with the increase of the open porosity under the two inlet conditions, but the increase amplitude is higher under the condition of constant pressure differential. When configurations have the same hole diameter and the same open porosity, the overall cooling effectiveness of the inclined multihole with 20° inclination angle of the flow is the highest under the condition of constant coolant flow rate. The overall cooling effectiveness of the inclined multihole with 30° inclination angle of the flow is the highest under the condition of constant pressure differential.