论文部分内容阅读
针对后混式高速水射流超细粉碎技术,采用理论分析、数值计算和粉碎实验相结合的方法对D 25和D 50两种加速管管型下的复杂流场做了分析,着重研究了多相流流动特性并提出了加速分区理论。研究结果表明:采用FLUENT软件包对多相射流流动进行模拟研究结果可靠;射流紊动、掺气和卷吸特性是多相射流相间能量传递和附加相获取一定的初始动能的主要方式;加速管管径对射流流动特性和粉碎效率影响显著,其管径越大水射流紊动越剧烈,能量耗散越快,对附加相加速不利且粉碎效率也越低;附加相加速存在明显的分区,分别为理想加速区(1 R)、内层高效加速区(1R 2 R)、外层高效加速区(2 R 3 R)和低效加速区(3 R);为了获取更高的粉碎效率,需采用较小管径加速管使颗粒尽量靠近射流理想加速区。
Aiming at the ultra-fine pulverization technology of post-mixed high-speed water jet, the complicated flow fields under D 25 and D 50 accelerating tube types are analyzed with theoretical analysis, numerical calculation and crushing experiments. Phase flow characteristics and proposed accelerated zoning theory. The results show that the simulation results of the multiphase jet flow with the FLUENT software package are reliable. The jet turbulence, aeration and entrainment characteristics are the main ways of energy transfer between the multiphase jet phase and the additional phase to obtain a certain initial kinetic energy. The diameter has a significant effect on the jet flow characteristics and crushing efficiency. The larger the tube diameter, the more turbulent the water jet, the faster the energy dissipation, the unfavorable additional phase accelerating and the lower the crushing efficiency. The additional phase accelerating has obvious partitioning, Namely 1 R 2 R, 2 R 3 R and 3 R, respectively. In order to obtain higher crushing efficiency, Requires a smaller diameter tube to keep the particles as close as possible to the jet’s ideal acceleration zone.