前混合磨料水射流除鳞喷嘴混合腔内部流场

Internal mixing chamber flow field of a premixed abrasive water jet descaling nozzle

基于计算流体动力学多相流混合物模型,应用FLUENT软件对前混合磨料水射流除鳞喷嘴高压水与磨料混合腔内部流场进行数值模拟.比较了不同进料方式对流场均匀性的影响.分析了两侧为高压水入口条件下,磨料入口直径、高压水入口直径、高压水入口位置和角度以及收缩段锥角对流场混合均匀性的影响,得到了影响混合腔内部流场混合均匀性的合理结构参数.数值计算结果表明:入口速度一定的条件下,磨料中进式喷嘴混合腔的混合均匀性优于磨料侧进式喷嘴混合腔.随磨料入口和高压水入口直径增加,混合腔出口的射流速度均增加,但随高压水入口直径增加导致出口磨料浓度呈先增后减的趋势,磨料入口与高压水入口合理的质量流量比值约为3∶4,两侧高压水入口位置对流场混合均匀性影响较小,高压水入口角度和收缩段锥角均为30°时流场性能更佳.

Numerical simulation was performed to study the internal mixing chamber flow field of a premixed abrasive water jet de-scaling nozzle by FLUENT software based on a CFD （computational fluid dynamics） multiphase flow mixture model. The effects of ab-rasive supply modes as well as different parameters under bilateral high-pressure water entrances such as abrasive and high-pressure wa-ter inlet diameters, high-pressure water inlet location and angle, and contraction cone angle on the flow field uniformity were analyzed to obtain reasonable structure parameters. Numerical calculation results show that the mixing uniformity of the internal mixing chamber for the abrasive entering by the central entrance mode is superior to that by the bilateral entrance mode at constant entrance velocity. The jet velocity out of the internal mixing chamber increases with the increasing abrasive and high-pressure water inlet diameters, but the outlet abrasive concentration increases firstly and then decreases as the high-pressure water inlet diameter increases. The location of bilateral high-pressure water entrances has relatively little effect on the mixing uniformity of the internal mixing chamber. When the mass flow ratio of abrasive to high-pressure water is about 3： 4, and when the high-pressure water inlet angle and contraction cone angle are set at 30°, a relatively uniform flow field can be obtained.