The Mechanism Of Liquid Columns’ Deformation And Breakup Process Under The Action Of Shock Wave

The deformation and breakup phenomenon produced by the different form of liquid under the action of shock wave is a typical problem of multiphase fluid mechanics, studying the mechanism of deformation and breakup of liquid has a lot of applications in engineering and science. Such as reduce the damage caused by rain droplets impinging on aircraft in a high-speed flight, improve the efficiency and stability of liquid fuel combustion in detonation engine and rocket engine, shock wave dispersal and so on. On the basis of the interaction between shock wave and single water column, an experiment investigation was carried out to the interaction between shock wave and multiple liquid columns in a horizontal shock tube, numerical simulation also was carried out for the experimental process, the purpose is to reveal the process of deformation and breakup of the water columns under the action of shock wave.The experimental study is conducted in a 3.5m long horizontal shock tube with rectangular cross section. By using electric diaphragm bursting device,we got plane shock wave with Mach 1.2. Using test device designed by self, we made multiple water columns in vertical direction, after shock wave impacted the water columns, high-speed camera recorded the deformation and breakup process of weter columns in vertical section and horizontal section by using the method of shadowgraph, direct light technology and planar laser sheet technology, and the experimental results were analyzed quantitatively, then we obtained the process and variations between the different number of water columns.The numerical simulations were completed by using a CFD software composed of Gambit and Fluent, and data post-processing softwares such as Tecplot, Origin, etc. Use the VOF model and standard k-εturbulence model, we simulated the experimental process of one and three water columns, and the physical characteristics of the liquid column and the surrounding flow field in the process of the interaction between the shock wave and the liquid column are obtained, further analyzed the deformation and breakup mechanism of the liquid columns.After analyzing the experimental results and numerical results, we got these conclusions: after shock wave interacting with liquid columns in the vertical direction, no matter what the number of liquid columns is, they will experience the process from compressive deformation to droplets stripping and the colunms will do accelerated motion, finally spike and bubble structure will be generated on the windward. Through quantitative measurement, we found the compressive deformation of liquid column starts from the movement of windward side, the axial mixing width of the liquid columns will decrease first, and then increase linearly, the displacement of liquid columns will increase nonlinearly, the more liquid columns, the faster becomes the mixing width, and the smaller becomes the speed of displacement. After quantitatively measuring the growth law of sipke and bubble in single liquid column and three liquid columns, we found it increase linearly with time, but the instability phenomenon is different in three liquid columns, the gowth speed of three columns is faster than the speed of single columns. The deformation process of liquid columns in horizontal direction was measured firstly by using planar laser sheet technology, the deformation model of liquid columns is similar to sheet stripping model of droplet, the lateral diameter of single liquid column will increase first, and then decrease, the lateral diameter of three liquid columns will increase first, and then decrease, then increase again. We got the change of shock wave in horizontal direction by numerical simulation, the change of three liquid columns is more complicated than single column, so the flow field characteristics is more complicated, the action of shock wave established the foundation. By 2d and 3d numerical simulation, we got the deformation and breakup process of liquid columns and the change of the flow field around columns, after quantitatively measuring the lateral diameter and spike and bubble of liquid columns, numerical simulation has the same change rule with the experiment, but restricted by calculation software, the numerical simulation data and experimental data have certain difference.