【作者】 丁猛；

【导师】 王振国；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2005， 博士

【摘要】 论文选取基于凹腔的超声速燃烧火焰稳定技术为研究对象,对凹腔燃烧流动过程和凹腔火焰稳定器性能进行了全面深入研究。在冷流条件下,研究了气体/液体喷流与凹腔流动之间的相互作用。结果表明:气体/液体喷流对凹腔整体流动特征的影响是一致的,凹腔上游/底壁喷流破坏了当地附面层或剪切层,导致凹腔剪切层偏向主流方向;凹腔前壁喷注对凹腔流场特征基本无影响。在燃烧状态下,对基于常温液体煤油燃料的凹腔火焰稳定器的燃烧与流动特征进行了试验研究,并比较了不同当量比和不同燃料喷注方式。研究发现:凹腔上游喷注的液体燃料能够迅速雾化、蒸发,并在较短距离内依靠对流输运过程进入凹腔内部;凹腔后壁始终是凹腔火焰驻留的主要区域,在贫油极限时,也是唯一区域,并存在明显的火焰由后壁向前壁的传播过程;燃烧状态下的凹腔剪切层以较大角度向下游主流发展,不再附着于凹腔后壁,与冷流中的凹腔流场特征相差较大。对基于常温液体煤油燃料的凹腔火焰稳定器的贫油稳焰范围进行了试验研究,比较了不同凹腔结构尺寸和不同喷注方式。研究发现:凹腔深度和长深比对凹腔火焰稳定器的贫油极限影响较大,贫油稳焰范围与深度、长深比成正比,随后壁倾斜角的增大先增大后减小。而且,贫油稳焰范围与稳焰效率受喷注方式影响较大,在凹腔上游喷注基础上,辅加凹腔底壁或凹腔前壁喷注都会减小稳焰范围、降低稳焰效率。利用直连式试验台推力测量系统,对凹腔火焰稳定器的阻力特性进行了试验研究,主要对不同喷注方式、不同当量比时的热试阻力特性进行了对比和分析。研究发现:凹腔火焰稳定器热试阻力小于冷流阻力,并随着当量比的增加而减小,最终会表现为正推力。综合论文研究成果,提出了多凹腔燃烧室设计技术。经过模型超燃冲压发动机和单模块超燃冲压发动机试验验证,该技术具有优良的火焰稳定性能,并有助于实现高效率燃烧。更多还原

【Abstract】 The flame holding technology based on cavity in supersonic combustion was studied systematically and comprehensively.The interaction between gas/liquid injection and cavity flow were studied in non-reaction flows. Results indicate that the characteristics of cavity flowfield were altered similarly by gas and liquid injection. The local boundary layer or shear layer are modified by injection on upstream/bottom wall of cavity, and the cavity shear layer immediately becomes angled with respect to the main flow direction. The injection on fore wall of cavity has little effect on the characteristics of cavity flowfield.The combustion and flow process of cavity flame holder with liquid kerosene fuel on room temperature were investigated experimentally, with different fuel equivalence ratio and injection schemes. It is found that the liquid kerosene of injection upstream cavity could finish the process of atomization and evaporation in short distance, and enter into cavity through convection. Aft wall is the primarily area of flame holding in cavity, and the only area when near the lean blowout limit, flame in area of fore wall are spread from it. Cavity shear layer in reaction flow angle greatly to the main flow direction, and couldn’t reattach to aft wall anymore, it appears great difference in characteristics of cavity flowfield between non-reaction and reaction state.Experiments on the lean blowout limit of cavity flame holder with liquid kerosene fuel on room temperature were conducted with various cavities and injection schemes. The result indicates that the range of stable lean operation varies greatly for different cavity depth D and length-depth-ratio L/D, it increases with increasing D and L/D, and increases, followed by decreasing with increasing incline angle of aft wall. Adding injection on bottom or fore wall of cavity, based on chief injections on upstream, provides worse lean flameholding performance.Experiments on the drag of cavity flame holder were conducted by force measurement system. The result of investigation on drags of cavities under combustion condition, with different injection schemes and fuel equivalence ratio, indicates that it is smaller than it’s of cold flow, and decreases with increasing fuel equivalence ratio, and could be converted into the更多还原