高速起动射流过程中可压缩涡环的生长演化及其对瞬时力的影响规律  

Formation and evolution of compressible vortex rings in highspeed starting jets and influence on instantaneous forces

作　　者：张济泽 向阳[1] 林海燕 黄小彬 刘洪[1] ZHANG Jize;XIANG Yang;LIN Haiyan;HUANG Xiaobin;LIU Hong(School of Aeronautics and Astronautics,Shanghai Jiaotong University,Shanghai 200240,China;AECC Commercial Aircraft Engine Co.,Ltd,Shanghai 200241,China)

机构地区：[1]上海交通大学航空航天学院,上海200240 [2]中国航发商用航空发动机有限责任公司,上海200241

出　　处：《推进技术》2024年第11期60-75,共16页Journal of Propulsion Technology

基　　金：国家自然科学基金青年基金(12202273)。

摘　　要：高速可压缩起动射流广泛存在于一些工程应用中,其射流过程伴随着复杂流动结构的演化,并对力和声有着显著的影响。为了研究高速起动射流过程中流场结构演化与瞬时力之间的关系,设计了一种开口激波管装置用于产生高速起动射流,并采用纹影和粒子成像测速技术(PIV)对高速起动射流产生的流场结构进行测量。与此同时,为了测量高速起动射流的瞬时力,将激波管悬挂并利用高动态微型力传感器直接测量高速起动射流产生的推力。PIV的实验结果表明,高速起动射流的流场主要包括三个阶段:入射激波离开喷口和后方流体迅速膨胀阶段;可压缩涡环卷起并快速生长阶段;可压缩涡环达到生长极限后的演化阶段。瞬时力测量结果显示,高速起动射流所产生的瞬时力呈现出先快速增长、随后缓慢下降的过程,并且瞬时力的峰值时刻与可压缩涡环发生夹止的时刻具有一致性。基于理论估算,进一步发现高速起动射流产生瞬时力峰值的机制主要是由于高速起动射流产生的大尺度可压缩涡环对周围的流体夹带进而带来的动量增益,也意味着可压缩涡环的生长演化产生了较强的非定常力的增益。进一步将喷口形状更换为锯齿型喷口,发现锯齿型喷口显著地减弱了可压缩涡环的环量,进而也降低了瞬时力的峰值,但是根据前人的研究,锯齿型喷口在降低噪声上具有明显的作用。High-speed compressible starting jets are widely used in a number of engineering applications,where the starting jet process is accompanied by the evolution of complex flow structures and has significant ef⁃fects on forces and sound.In order to investigate the relationship between the evolution of flow field structure and instantaneous forces during high-speed starting jets,an open-ended shock tube device is designed to generate high-speed starting jets,and the flow field structure generated by high-speed starting jets is measured by using schlieren and particle imaging velocimetry(PIV).And in order to measure the instantaneous force of high-speed starting jet,the shock tube was suspended,and a high fundamental frequency miniature load sensor was utilized to directly measure the thrust generated by high-speed starting jet.The experimental results of PIV show that the flow field of a high-speed starting jet consists of three main phases:rapid expansion of the fluid behind the inci⁃dent shock leaving the nozzle,a compressible vortex ring that coils up and grows rapidly,and the compressible vortex ring growing to its limit(pinch-off).The results of the instantaneous force measurements show that the in⁃stantaneous force generated by the high-speed starting jet shows a rapid growth followed by a slow decline,and the peak moment of the instantaneous force is consistent with the moment of the compressible vortex ring pinchoff.Theoretical estimation further indicates that the mechanism of the peak instantaneous force generated by the high-speed starting jet is mainly due to the large-scale compressible vortex ring generated by the high-speed starting jet on the surrounding fluid entrainment and thus the resulting momentum gain,which also implies that the growth and evolution of the compressible vortex ring produces a strong unsteady force gain.The nozzle shape is further replaced with lobed chevron nozzles,and it is found that the lobed chevron nozzles significantly reduce the circulation of the compressible vortex

关 键 词：高速起动射流 可压缩涡环 瞬时力 非定常空气动力学 粒子成像测速技术 

分 类 号：V211.1[航空宇航科学与技术—航空宇航推进理论与工程]