Hydrodynamics of spray/wall interaction

所提出的研究旨在实验和理论/数值研究的流体动力学的喷雾冲击刚性目标。喷雾冲击到这样的目标上，会在目标上形成一个移动的、波动的液体膜。膜内的流动是由单滴撞击和膜内的相互作用引起的。在某些情况下，这种相互作用会导致不稳定的上升层和射流的产生，并产生二次液滴的流动。在这个项目的框架内，将建造一个实验装置来详细研究喷雾对刚性目标的影响。该装置将包括一个容纳可交换目标的测试室（不同直径的球体，平坦透明），喷嘴系统，液体流动回路，相位多普勒仪器，穿越系统和高速摄像机。通过改变喷嘴、管路内压力、喷嘴与目标的距离及其倾斜角，可以改变冲击喷雾的特性。将测量由喷雾形成的薄膜的特征速度和厚度；二次液滴的通量将被表征。将对喷雾冲击产生的表面液膜进行建模，考虑该膜波动的惯性、体积通量和冲击喷雾的动量。作为研究的结果，我们期望开发一个喷雾冲击模型，该模型可以在喷射系统（燃油喷射，喷涂，喷雾冷却等）的欧拉-拉格朗日模拟中实现。

The proposed research is aimed at experimental and theoretical/numerical investigation of the hydrodynamics of spray impact onto a rigid target. Spray impacting onto such target creates on it a moving, fluctuating, liquid film. The flow in the film is caused by single drop impacts and by interactions in this film. In some cases such interactions lead to the creation of uprising sheets and jets which are unstable and create a flow of secondary droplets. Within the framework of this project an experimental setup for detailed investigation of spray impact onto a rigid target will be constructed and built. The set-up will consist of a test chamber accommodating exchangeable targets (spheres of different diameters, flat transparent), and the nozzle system, the liquid flow loop, phase-Doppler instrument, the traversing system, and a high-speed video camera. By changing the nozzles, the pressure in the line, the distance from the nozzle to the target and its inclination angle, the characteristics of the impacting spray will be varied. The characteristic velocity and thickness of the film created by the spray will be measured; the flux of secondary drops will be characterized. The liquid film on the surface, produced by the spray impact, will be modeled, accounting for the inertia of the fluctuations in this film, the volume flux and the momentum of the impacting spray. As the result of the study we expect to develop a model of spray impact which can be implemented in Euler-Lagrange simulations of spray systems (fuel injection, spray coating, spray cooling, etc.).