淹没磨料射流涡旋特性大涡模拟及研究

发布时间：2018-03-31 19:05

本文选题：淹没射流　切入点：磨料　出处：《振动与冲击》2016年19期

【摘要】：基于涡运动理论,采用固-液两相大涡模拟方法模拟了淹没磨料射流的涡量场,分析了涡旋扩散机理与卷吸特性以及磨料随涡运动在射流中的混合分布规律。流场剪切层中涡旋呈对称分布,沿轴线方向涡量呈指数衰减,衰减到最小值两侧涡旋混合成紊流混合区,而等速核内涡量几乎为零。相比于纯水射流,磨料的存在使得射流涡运动减弱,涡旋扩散角减小约50%,等速核增长约30%,减少了能量耗散。磨料在射流束内部时,受涡旋影响,趋向分布于高应变率、低涡量区,在涡旋下游侧磨料浓度最高。同时模拟研究了磨料参数对涡量场的影响规律,结果表明:磨料参数基本不影响扩散角(14.1°~15.1°)、等速核长度,卷吸能力随磨料浓度、粒径、密度的升高均呈现小幅度地降低,磨料密度对其影响程度最大,磨料粒径的影响最不明显。
[Abstract]:Based on the theory of vortex motion, the vorticity field of submerged abrasive jet is simulated by solid-liquid two-phase large eddy simulation method. The vortex diffusion mechanism, entrainment characteristics and the mixing distribution of abrasive with vortex motion in the jet are analyzed.In the shear layer of the flow field, the vortex is symmetrically distributed, and the vorticity is exponentially attenuated along the axis, and the vortex is mixed to the turbulent mixing region at both sides of the minimum value, while the vorticity in the isokinetic nucleus is almost zero.Compared with pure water jet, the existence of abrasive makes the vortex motion weaken, the vortex diffusion angle decrease about 50 and the isokinetic nucleus increase about 30 percent, thus reducing the energy dissipation.Under the influence of vortex, the abrasive tends to distribute in the region of high strain rate and low vorticity, and the abrasive concentration is the highest in the downstream side of vortex.At the same time, the effects of abrasive parameters on vorticity field are simulated. The results show that the abrasive parameters have no effect on diffusion angle 14.1 掳~ 15.1 掳, and the length of isokinetic nucleus and entrainment ability decrease slightly with the increase of abrasive concentration, particle size and density.The effect of abrasive density is the greatest, and the influence of abrasive particle size is the least.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室;重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室;
【基金】：国家重点基础研究发展计划(2014CB239206) 国家自然科学基金青年基金项目(51404045) 长江学者和创新团队发展计划(IRT13043)
【分类号】：O35

【相似文献】