超燃冲压发动机燃烧室出口温度场分布CARS测量

Outlet Temperature Measurements of Scramjet Combustor Using Coherent Anti-Stokes Raman Scattering

针对超燃冲压发动机研究中对燃烧室出口温度场的测量需求以及暂冲式超燃冲压发动机燃烧台架试验中的应用难点,开发了适用于瞬态燃烧场温度测量的单脉冲相干反斯托克斯拉曼反射(CARS)系统及CARS光谱计算和温度反演软件CARSCF。采用USED相位匹配方式来降低湍流影响,结合多尺度小波分析方法来实现CARS光谱降噪处理,提高信噪比。在暂冲式脉冲燃烧风洞上开展了来流马赫数2.6条件下超燃冲压发动机燃烧室出口温度测量试验,获取了超声速来流(冷态)建立、H_(2)点火加热空气、建立超声速燃烧流场直至试验结束过程中的燃烧室出口温度,以及煤油/空气燃烧时燃烧室出口温度场分布。结果显示,超声速冷流时温度处于低温(约205K)状态,随着H_(2)点火加热来流空气,来流温度上升至853K;随着煤油/Air点火,温度急剧上升,稳定燃烧状态下燃烧流场温度为1970K±144K。燃烧室出口截面温度场分布测量结果显示,高温区位于燃烧室出口截面上侧区域,而燃烧室出口截面上中间区域的温度低于上下两侧。燃烧室出口温度分布CARS测量结果与火焰自发光成像结果一致,表明单脉冲CARS技术用于瞬态燃烧流场温度测量的可行性。

For outlet temperature distribution measurement requirement of combustor and overcoming difficulties of engine ground test in scramjet,an USED-CARS system and a CARS spectra calculating program CARSCF has been developed for instantaneous temperature measurement. The USED phase matching method has been used to reduce turbulence effects. Multi-scale wavelet analysis has been used to reduce noise and improve the signal-to-noise ratio. The CARS measurement of scramjet combustor outlet temperature distribution with Mach 2.6 was performed at a pulse combustion facility. Temperatures of supersonic cold air flow,high temperature air and supersonic combustion were measured,and outlet temperature distributions of combustor were obtained. The results show that temperature of supersonic flow was 205K at cold air state,then raised to 853K after the air heating process by H_(2)combustion. With the kerosene/air igniting,temperature increased sharply to 1970K with a fluctuation(i.e. standard deviation)of 144K at stable combustion state. The high temperature areas of combustor outlet were on the upper side of combustor,while temperature of center area was lower than the upper and lower sides. The CARS measured outlet temperature distribution data from combustor are consistent with results measured by flame chemiluminescence,indicating the practicability of single pulse CARS for instantaneous temperature measurement in practical scramjet combustion flow.