气液两相射流破岩流场数值模拟

Numerical Simulation of Rock Breaking Flow Field by Gas-liquid Two-phase Jet

为解决传统水射流破岩资源消耗巨大的问题,急需研究出一种高效节能的射流破岩技术,以达到节能减排、绿色可持续发展的目的。基于计算流体力学方法,在水射流的基础上加入定量气相,形成气液两相射流,并对其进行数值仿真,研究了气液两相射流的速度场、压力场特性,分析了气相体积分数、入射压力和喷距对气液两相射流破岩性能参数的影响规律。研究结果显示:气相体积分数为30%的气液两相射流的最大轴向速度为288 m/s,相比纯水射流提升超过19%。当射流从喷嘴喷出,高压的气泡溃灭会形成高速溃灭微射流,提高射流速度和射流冲击力。随气相体积分数增加,射流最大轴向速度不断增加,而驻点压力略有下降。随入射压力增加时,射流最大轴向速度呈上升趋势,但增幅逐渐变缓。当喷距增加到35 mm时,射流中的大部分气泡在靶面附近发生溃灭,对靶面产生脉动冲击,使驻点压力回升到26 MPa,此时驻点压力高,射流扩散较小,射流破岩性能良好。

In order to solve the problem of huge consumption of traditional water jet rock breaking resources, it is urgent to develop an efficient and energy-saving jet rock breaking technology in order to achieve the purpose of energy conservation, emission reduction and green sustainable development. Based on the computational fluid dynamics method, the quantitative gas phase was added to the water jet to form the gas-liquid two-phase jet, and its numerical simulation was carried out. The characteristics of the velocity field and pressure field of the gas-liquid two-phase jet were studied, and the effects of gas volume fraction, incident pressure and jet distance on the rock breaking performance parameters of the gas-liquid two-phase jet were analyzed. The results show that the maximum axial velocity of gas-liquid two-phase jet with gas volume fraction of 30% is 288 m/s, which is more than 19% higher than that of pure water jet. When the jet is ejected from the nozzle, the high-pressure bubble collapse will form a high-speed collapse micro jet, which will improve the jet velocity and jet impact force. With the increase of gas volume fraction, the maximum axial velocity of jet increases, while the stagnation point pressure decreases slightly. With the increase of incident pressure, the maximum axial velocity of jet increases, but the increase decreases gradually. When the jet distance increases to 35 mm, most of the bubbles in the jet collapse near the target surface and produce pulsating impact on the target surface, so that the stagnation point pressure rises to 26 MPa. At this time, the stagnation point pressure is high, the jet diffusion is small, and the rock breaking performance of the jet is good.