基于FLUENT的三维旋转射流流场分析及喷头结构优化

Flow Field Analysis and Nozzle Structure Optimization for Three Dimensional Rotating Water Jetting Based on FLUENT

为优化设计三维旋转水射流喷头内部结构,利用fluent进行喷头内部结构对射流效果影响规律的数值模拟计算,分析了叶轮导向角分别为15°-75°时的射流流场特征,得出三维旋转水射流喷头叶轮导向角最优值为45°,并分析了喷头绕轴旋转时的流场特征。对根据数值模拟结果研制的喷头及配套钻孔扩孔装备进行实验室试验和现场应用检验,结果表明,三维旋转水射流扩孔直径可达2.3倍、百米钻孔瓦斯抽采纯量最大可达常规钻孔1.79倍、59 d抽采率提高了79.3%,在低透煤层增透方面应用效果显著。

To optimize the structure of three dimensional rotating water jet nozzles, the influence of internal structure of nozzles on the jet effect was simulated by fluent. The characteristics of jet flow field were analyzed when impeller orientation angle is distributed from 15° to 75° ; it obtained that the optimum orientation angle is 45°, and the characters of flow field were analyzed when the nozzle was rotated by its axis. The nozzle and matching equipment according the simulation results were tested and experimented in laboratory and field application; the result shows that three dimension rotating water jet enlarging the hole diameter is up to 2.3 times; the pure gas extraction quantity in hundreds of meters drilling is up to 1.79 times of normal drilling; the gas extraction ratio are increased by 79.3% in 59 days, it has better effect for low permeability coal seam.