中文摘要：

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。

英文摘要：

In this paper,it is emphasized to study the multiphase jet flow characteristics and to propose accelerated subarea theory.Based on combining methods of theoretical analysis,numerical calculation and crushing experiment,the complex flow distribution for two kinds of acceleration tubes whose diameters are and was researched,which focuses on the super fine crushing technology concerning rear-mixed high-speed water jet flow.Some results were obtained as follows：（1） It is reliable that using FLUENT software to simulate multiphase jet flow.（2） Jet flow turbulent motion,aeration and entrainment characteristics are main ways to transfer multiphase jet flow interphase energy and obtain some initial kinetic energy for additional phase.（3） The diameter of accelerating tube has significant effect on flow characteristics and grinding efficiency.The larger diameter and the more violent water jet turbulent motion,the faster energy dissipation,which has adverse effect on additional phase and lead to lower grinding efficiency. There are obvious division in the additional phase acceleration,which are ideal accelerated zone,inner layer efficient accelerated zone,outer layer efficient accelerated zone and inefficient accelerated zone respectively. In order to obtain a higher grinding efficiency,the smaller diameter tube was adopted to make the accelerating particles as close to jet ideal accelerated zone as possible.