Hydrodynamics of spray/wall interaction

建议的研究是针对实验和理论/数值研究的流体动力学喷雾冲击到一个刚性的目标。喷雾冲击到这样的目标上，在其上产生移动的、波动的液体膜。膜中的流动由单滴冲击和膜中的相互作用引起。在某些情况下，这种相互作用导致产生不稳定的上升片和射流，并产生二次液滴流。在本项目的框架内，将建造和建造一个实验装置，用于详细研究喷雾对刚性目标的影响。该装置将包括一个可容纳可更换目标（不同直径的球体，平面透明）的试验室，以及喷嘴系统、液体流动回路、相位多普勒仪器、横向系统和高速摄像机。通过改变喷嘴数目、管路压力、喷嘴与靶板的距离以及喷嘴倾角，可以改变冲击喷雾的特性。将测量由喷雾产生的膜的特征速度和厚度;将表征二次液滴的通量。将对由喷雾冲击产生的表面上的液体膜进行建模，考虑该膜中波动的惯性、体积通量和冲击喷雾的动量。作为研究的结果，我们希望开发一个模型的喷雾影响，可以实现在欧拉-拉格朗日模拟的喷雾系统（燃料喷射，喷涂，喷雾冷却等）。

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.).