Laser sheet dropsizing of evaporating sprays using simultaneous LIEF/MIE techniques
Laser sheet dropsizing of evaporating sprays using simultaneous LIEF/MIE techniques
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DOI：
10.1016/j.proci.2012.07.061
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
W. Zeng;Min Xu;Yuyin Zhang;Zhenkan Wang
中科院分区：
文献类型：
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作者：
W. Zeng;Min Xu;Yuyin Zhang;Zhenkan Wang
激光诱导荧光/米氏散射（LIF/MIE）被证明是一个有用的诊断非蒸发喷雾的索特平均直径（SMD）测量。然而，由于来自气相的荧光信号的干扰，对于蒸发喷雾的情况，测量是不可靠的。本文采用激光诱导激基复合物荧光/米氏散射（LIEF/MIE）成像技术对蒸发喷雾的SMD分布进行了研究。采用一种特殊的实验条件来产生闪蒸喷雾，该条件包括燃料温度为60°C和环境压力为20 kPa。与传统的LIF/MIE技术不同，LIEF和Mie技术的组合允许消除来自蒸发喷雾中的气相的示踪剂荧光的影响。此外，仔细选择的示踪剂和专门设计的过滤器被用来减少在蒸发过程中的示踪剂浓度和荧光强度的温度依赖性的变化的影响。采用基于几何光学近似（果阿）的数值分析和实验分析相结合的方法确定了标定系数K。最后，通过LIEF/MIE和传统的LIF/MIE技术测量的蒸发喷雾SMD分布进行了比较，PDI测量。结果表明，用LIEF/MIE方法得到的闪急沸腾喷雾的SMD与用PDI方法得到的SMD非常接近，而用LIF/MIE方法和PDI方法得到的喷雾SMD存在较大的偏差，偏差在40%左右。结果表明，对于蒸发喷雾，蒸发效应是不可忽略的。
Laser-induced-fluorescence/Mie-scattering (LIF/MIE) was proven to be a useful diagnostic for Sauter Mean Diameter (SMD) measurements in non-evaporating sprays. However, the measurement is not reliable for cases of an evaporating spray due to the interference of the fluorescence signal from the vapor phase. In this work, simultaneous Laser-induced-exciplex-fluorescence/Mie-scattering (LIEF/MIE) imaging techniques were proposed to obtain the SMD distribution of evaporating sprays. A special experimental condition was used to generate the flash-evaporating spray, which includes a fuel temperature of 60°C and an ambient pressure of 20kPa. Different from the conventional LIF/MIE technique, the combination of LIEF and Mie techniques allows eliminating the effect of tracer fluorescence from vapor phase in an evaporating spray. In addition, carefully selected tracers and specially designed filters were used to decrease the effects of variation on tracer concentration and temperature dependency of fluorescence intensity during evaporation. The numerical analysis based on geometrical optics approximation (GOA) and experimental analysis was conducted to determine the calibration coefficient K. Finally, SMD distribution of an evaporating spray measured by both LIEF/MIE and conventional LIF/MIE techniques was compared to PDI measurement. The results show that the SMD of the flash boiling spray obtained from LIEF/MIE is very close to those measured by PDI, while the results measured by LIF/MIE and PDI show a large deviation of around 40%. It indicates that the evaporation effect cannot be ignored for evaporating sprays.