Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.
Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.
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DOI：
10.1364/oe.24.002542
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发表时间：
2016-02
期刊：
影响因子：
3.8
通讯作者：
S. Henkel;F. Beyrau;Y. Hardalupas;A. M. Taylor
中科院分区：
文献类型：
--
作者：
S. Henkel;F. Beyrau;Y. Hardalupas;A. M. Taylor
本文介绍了一种新的光学技术的发展和应用，用于测量在汽车燃油喷雾碰撞过程中形成的表面上的液体膜厚度。该技术利用已知粗糙度的金属表面的光散射特性的变化，当液体沉积。该技术相对于先前建立的方法的重要优点是能够测量液体膜的时间依赖性空间分布，而不需要向液体中添加荧光示踪剂，同时测量原理不受液体或周围气相的压力和温度变化的影响。此外，不需要不发荧光的替代燃料。然而，需要对信号强度对液膜厚度的依赖性进行原位校准。该方法可用于测量缸内直喷式汽油机活塞或缸套表面液体油膜厚度随时间变化的二维分布。该技术的适用性进行了评估与几个直链烷烃和醇类具有不同的热物理性质的碰撞喷雾。对冲击板表面温度进行了控制，以模拟缸内直喷发动机活塞表面温度的变化范围。获得了两组液膜厚度测量值。在第一组中，板的表面温度保持恒定，而不同燃料的喷雾与表面相互作用。在第二组中，调整板温度以匹配每种燃料的沸腾温度。通过这种方法，可以证明表面温度对不同燃料的喷雾形成的液膜的影响及其蒸发特性。
This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated.