Taber Wanstall C, Agrawal Ajay K, Bittle Joshua A
Appl Opt. 2017 Oct 20;56(30):8385-8393. doi: 10.1364/AO.56.008385.
The rainbow schlieren deflectometry (RSD) technique is used to determine the liquid boundary and the fuel volume fraction distributions in the vapor region of a high-pressure fuel spray. Experiments were conducted in a constant pressure flow vessel, whereby a customized single-hole common-rail diesel injector is used to introduce n-heptane fuel into a coflow of low-speed ambient air at two different test conditions. Only the quasi-steady period of the fuel spray is considered, and multiple injections are performed to acquire statistically significant data at an image acquisition rate of 20 kHz. An algorithm to identify the liquid boundary using intensity recorded by the RSD images is presented. The results are compared against measurements obtained by the Mie scattering technique. Results demonstrate that the RSD can be a powerful optical diagnostics technique to simultaneously quantify both the vapor and liquid regions in the high-pressure fuel sprays.
彩虹纹影偏折测量（RSD）技术用于确定高压燃油喷雾蒸汽区域中的液体边界和燃油体积分数分布。实验在恒压流动容器中进行，使用定制的单孔共轨柴油喷油器在两种不同测试条件下将正庚烷燃料引入低速环境空气的同向气流中。仅考虑燃油喷雾的准稳态阶段，并进行多次喷射以在20kHz的图像采集速率下获取具有统计意义的数据。提出了一种利用RSD图像记录的强度来识别液体边界的算法。将结果与通过米氏散射技术获得的测量结果进行比较。结果表明，RSD可以成为一种强大的光学诊断技术，用于同时量化高压燃油喷雾中的蒸汽和液体区域。
