Evaluation of parallel injector configurations for Mach 2 combustion
Evaluation of parallel injector configurations for Mach 2 combustion
复制标题
马赫 2 燃烧的并行喷射器配置的评估
DOI：
10.2514/3.23503
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
D. Capriotti
中科院分区：
文献类型：
--
作者：
G. Northam;I. Greenberg;C. Byington;D. Capriotti
为了探索超燃冲压发动机燃烧室内强化混合的技术，进行了壁挂式平行喷油器坡道的试验研究。下游平行喷射在高速时可能有助于从用于冷却发动机和机身的氢气中提取推力。这里使用的后掠式斜坡式喷油器应该会产生涡流脱落和局部分离(如向后的台阶)，这应该会加强混合。在后掠坡道下游增加了垂直喷油器，以确定平行喷油器在没有燃油喷射的情况下产生的涡流是否有效地增强了横向燃油射流的混合。为了进行性能比较，还测试了未扫过但在其他方面完全相同的并行喷油器。喷油器坡道的设计是为了从管道顶壁产生反射冲击波，使其正好通过喷油器筒体激波的下游。喷油器出口处的马赫数被设计为1.7，以在几乎所有运行条件下产生欠膨胀的燃油流量。在整个温度范围内，使用受污染的加热器进行了直接连接测试。采用阴影摄影和紫外电视摄像系统进行了非导管自由喷流态下的流动显示试验。测试了三种风管配置。在喷射器区块下游有一条100 mm等面积管道的后掠坡道的试验结果表明，在几乎任何当量比下，上游都会产生干扰。增加管道扩张率可以使当量比增加到1.5以上，并在较宽的总温度范围内快速混合和燃烧。未掠过的坡道设计导致燃烧效率较低，并且效率对加热器总温度或风道速度的敏感性较高。
An experimental study of wall-mounted parallel injector ramps has been conducted to explore techniques to enhance mixing in a scramjet combustor. Downstream parallel injection may be useful at high speeds to extract thrust from hydrogen that has been used to cool the engine and the airframe. The swept ramp fuel injector employed here should produce vortex shedding and local separation (like a rearward-facing step), which should enhance mixing. Perpendicular fuel injectors were added downstream of the swept ramps to determine if the vortical wake flow generated by the parallel injectors—with no fuel injection—is effective in enhancing the mixing of the transverse fuel jet. For performance comparisons, an unswept, but otherwise identical, parallel injector was also tested. The injector ramps were designed to yield a reflected shock wave from the duct top wall such that it passed just downstream of the barrel shock of the fuel injectors. The Mach number at the exit of the fuel injector was designed to be 1.7 to produce an underexpanded fuel flow under almost all operating conditions. Direct-connect tests were conducted with a vitiated heater over a total temperature range. Flow visualization tests with an unducted freejet configuration were conducted using shadowgraph and ultraviolet television camera systems for OH radical visualization. Three duct configurations were tested. Tests of the swept ramp with a 100-mm constant-area duct downstream of the injector block resulted in upstream interaction at almost any equivalence ratio. Increasing the duct expansion rate allowed the equivalence ratio to be increased beyond 1.5 with rapid mixing and combustion over a wide total temperature range. The unswept ramp design resulted in lower combustion efficiency and a sensitivity of efficiency to heater total temperature, or duct velocity.