Hydrodynamics of spray/wall interaction

这项研究旨在对喷雾撞击刚性靶板的流体力学进行实验和理论/数值研究。喷雾撞击到这样的靶子上会在其上产生一层运动的、波动的液膜。薄膜中的流动是由单液滴撞击和薄膜中的相互作用引起的。在某些情况下，这种相互作用会产生不稳定的上升薄片和喷流，并产生二次液滴流动。在这个项目的框架内，将建造一个喷雾撞击刚性目标的详细研究的实验装置。该装置将包括一个容纳可交换目标(不同直径的球体，平面透明)的测试室，以及喷嘴系统、液体流动回路、相位多普勒仪、穿越系统和高速摄像机。通过改变喷嘴、管道内的压力、喷嘴到靶体的距离及其倾角，可以改变撞击喷雾的特性。将测量喷雾形成的膜的特征速度和厚度；将表征二次液滴的流量。将对喷雾撞击产生的表面液膜进行建模，考虑了液膜中波动的惯性、撞击喷雾的体积流量和动量。作为这项研究的结果，我们希望开发一个喷雾冲击模型，该模型可以在喷雾系统(燃油喷射、喷雾涂层、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.).