扩张型面内超声速气流中液体横向射流穿透深度试验研究

Experimental Study on Penetration Depth of Transverse Liquid Jet in a Supersonic Flow in Expanded Section

关键词:  超声速气流  喷注雾化  射流  试验  扩张型面  流场

Key words:  Supersonic flow  Spray atomization  Jet  Experiment  Expanded section  Flow field

摘要:

基于冲压旋转爆震发动机应用，设计了带隔离段及等直燃烧室的矩形带扩张型面，开展常温常压吸气式超声速风洞中的液体横向射流试验，借助高速摄影、阴影方法研究来流参数、喷孔参数对喷注雾化穿透深度及液雾扩展效果的影响。研究表明：隔离段到燃烧室的过渡构型在气相流场中产生了较强的膨胀波和压缩波，直接扰动射流的二次雾化，液体射流破碎、雾化和液雾掺混的过程受到影响。总温总压一定时，来流马赫数增大、喷注压降增大均可提高液气动量通量比，从而增大射流穿透深度。同样的穿透深度情况下，利用小喷孔高压降喷注方式可以较为明显地减小激波角度。与增大孔径相比，同样的流量条件下增大射流压降可有效增加穿透深度提升程度，获得更好的液雾掺混效果。

Abstract:

Towards the application of the promising air-breathing rotating detonation engine （RDE）， a rectangular expansion configuration with an isolation section and a straight combustor was designed， and the atomization process experiment of transverse jets in aspirating supersonic wind tunnel at normal temperature and pressure was carried out. The influence of incoming flow parameters and orifice parameters on the spray’s penetration depth and expansion effect was studied by employing high-speed photography and shadow methods. It was shown that： the transition configuration from the isolation section to the combustor produces strong expansion waves and compression waves in the gas flow field， directly disturbing the secondary atomization， thereby influencing the process of liquid jet breaking， atomization， and spray mixing. Holding the total temperature and pressure constant， the increase in the incoming Mach number and the injection pressure drop can both increase the liquid-air momentum flux ratio， thereby increasing the jet penetration depth. Under the same penetration depth， the shock wave angle can be significantly reduced by using a small orifice with high injection pressure drop. Compared with increasing the diameter of the orifice， increasing the liquid injection pressure drop under the same flow rate can improve the penetration depth effectively and obtain a better mixing effect.