一种蒸发式凹腔驻涡值班稳定器的流动与点火性能研究

Flow Characteristics and Ignition Performance Analysis of an Evaporating Cavity Trapped Vortex Pilot Flame-Holder

为进一步拓宽凹腔驻涡值班稳定器在低温、高速来流条件下的点熄火边界,提出了一种利用高温燃气预热、预混供油的蒸发式凹腔驻涡值班稳定器。研究了蒸发式凹腔驻涡值班稳定器的流动特性、燃油分布特性及点火性能。研究结果表明:蒸发式凹腔驻涡值班稳定器的掺混腔和凹腔内部形成的涡系结构为低温、高速来流下的点火和燃烧提供了有利条件。凹腔驻涡区的气相油雾沿流向分布均匀,沿周向从稳定器对称子午面最富递减到相邻稳定器中间面最贫。在相同来流温度下,蒸发式凹腔驻涡值班稳定器的贫油点火和熄火当量比均随着来流速度的增大而增大。在低温(600K)、高速(100~200m/s)来流条件下,相比于蒸发式Z形值班火焰稳定器和常规薄膜蒸发式火焰稳定器,蒸发式凹腔驻涡值班稳定器贫油点火当量比能分别降低5.5%和30%;其贫油熄火当量比能分别降低37.4%和48.8%。

In order to further broaden the ignition and blowout boundary of the cavity trapped vortex flameholder at low temperature and high speed flow conditions,a novel preheated and premixed fuel supply method us⁃ing core hot gas,is proposed for the evaporating cavity trapped vortex pilot flame-holder.The flow characteris⁃tics,fuel distribution characteristics and ignition performance under wide range flow conditions of evaporating cavity trapped vortex pilot flame-holder are obtained.The results show that the vortex structure formed inside the cavity and mixing chamber of the evaporating cavity trapped vortex pilot flame-holder provide favourable condi⁃tions for ignition and combustion at low temperature and high speed.The fuel spray distribution in the vortex zone of the cavity is evenly distributed in the flow direction,and decreases from the richest of the symmetrical meridi⁃an surface of the flame-holder to the poorest of the middle surfaces of the adjacent flame-holder along the circum⁃ferential direction.At the same flow temperature,the lean ignition and blowout equivalent ratio of the evaporating cavity trapped vortex pilot flame-holder increases with the increase of the inlet speed.Under low temperature(600K),high speed(100~200m/s)flow conditions,compared with evaporating Z-shaped flame-holder and tra⁃ditional film evaporation flame-holder,evaporating cavity trapped vortex pilot flame-holder can decrease the ig⁃nition equivalent ratio by 5.5%and 30%,respectively.Blowout equivalent ratio can be decreased by 37.4%and 48.8%,respectively.