射流角与吹风比影响涡发生器强化气膜冷却性能的实验研究

Experimental Study of Impact of Inclination Angle and Blowing Ratio on Vortex Generator Enhancing Film Cooling Effectiveness

关键词:  涡发生器  气膜冷却  吹风比  射流角度  实验研究

Key words:  Vortex generator  Film cooling  Blowing ratio  Inclination angle  Experimental study

摘要:

为了研究了射流角度和吹风比等关键参数对涡发生器强化气膜冷却性能的影响规律，采用热电偶测温和粒子成像测速(Particle Image Velocimetry，PIV)技术，在搭建的气膜冷却实验台上对三种不同射流角度(α=20°， 30°， 40°)的带涡发生器和不带涡发生器等六种结构在三种不同吹风比(M=0.5， 1.0， 1.5)下的壁面气膜有效度分布及中截面流场结构进行了研究。结果表明:涡发生器的引入能显著提高气膜冷却性能，面平均气膜有效度最高提升达249%；不带涡发生器结构的气膜冷却性能随吹风比及射流角增大均呈现降低趋势；20°和30°射流角情况，带涡发生器结构的气膜冷却性能随吹风比增大而逐渐增大，而对于40°射流角则反之；M=0.5情况下，带涡发生器结构的气膜冷却性能随射流角增大而略微增大，在M=1.5情况下，规律相反，而在M=1.0情况下，射流角度基本无影响。

Abstract:

To study the impact of inclination angle and blowing ratio on vortex generator enhancing film cooling effectiveness， the thermocouples were used to measure the film cooling effectiveness， the technology of particle image velocimetry (PIV) was used to capture the flow structure， and thus the effects of critical parameters such as inclination angle and blowing ratio on enhancing the film cooling effectiveness were investigated. The distribution of film cooling effectiveness and the flow structure at mid-span of geometries with and without vortex generators were measured at different inclination angles(α=20°， 30°， 40°) and blowing ratios(M=0.5， 1.0， 1.5). It is indicated that the vortex generator would significantly improve the film cooling effectiveness and the area-averaged film cooling effectiveness improves 249% at most. The film cooling effectiveness of the geometry without vortex generator would be decreased when the blow ratio and the inclination angle become larger. With the inclination angle of 20° and 30°， the film cooling effectiveness of the geometry with vortex generator would increase as the increase of blowing ratio. However， the film cooling effectiveness of corresponding geometry would be deteriorated with the inclination angle of 40°. When M=0.5， the film cooling effectiveness of the geometry with vortex generator would slightly increase as the increase of inclination angle， however， an opposite trend is shown when M=1.5. The effect of inclination angle becomes negligible when M=1.0.