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非牛顿射流的撞击破碎在液体火箭推进系统中被广泛用于燃料的喷注雾化,然而人们对其破碎物理机制却知之甚少。本文将采用基于液体体积法的直接数值模拟(DNS)工具,研究夹角为90°的2个等直径低韦伯数射流撞击现象,并分析二者形成的单一对角射流特征及其破碎机理。研究结果表明,撞击形成的单一对角射流直径较原射流直径大1.66倍,并在头部形成液滴诱导破碎的发生。除了头部破碎,在对角射流的发展过程中还观察到一类液柱破碎,表现为射流表面不稳定波不断发展形成新的弯曲波破碎,并产生卫星液滴及液滴的融合。伴随两股射流撞击的发生,气液两相交界面的面积也不断减小,同时,射流内部的黏性也不断变化,在本文的低雷诺数和低韦伯数条件下,流体内部黏性系数变化超过10%。
Impulse crushing of non-Newtonian jets is widely used in the liquid rocket propulsion system for the atomization and atomization of fuel. However, little is known about the physical mechanism of its fragmentation. In this paper, we use the direct numerical simulation (DNS) tool based on the liquid volume method to study the impact phenomena of two equal-diameter Weber jets at an equal angle of 90 ° and analyze the single diagonal jet characteristics and the crushing mechanism. The results show that the diameter of the single diagonal jet formed by the impact is 1.66 times larger than the diameter of the original jet, and droplets form on the head to induce the fracture. In addition to head fragmentation, a type of liquid column fragmentation is also observed during the development of diagonal jets, which is characterized by the continuous development of jerk waves on the jet surface resulting in the breakage of new flexural waves and the fusion of satellite droplets and droplets. With the collision of two jets, the area of the interface between gas and liquid also decreases continuously. At the same time, the viscosity of the jets changes continuously. Under the low Reynolds number and low Weber number, the internal viscosity of the fluid changes Over 10%.