新型旋转射流多孔喷嘴流场的分析

摘要

A new kind swirling multi-orifices nozzle for radial horizontal drilling technology was presented.There were three for-ward orifices with different tangential inclination uniformly distributed in the front face.The inclination angles were 15°,30°and 45°.Three dimensional flow fields of the nozzle were simulated in terms of RNG k -ε turbulent model,also compared with the ex-periment result.The result shows that the 15°orifice has larger axial velocity and poor diffusivity,so the velocity decays just like the normal jetting and the efficiency of rock breaking is moderate;the 30°orifice has larger axial velocity,radial velocity,tangential velocity and moderate diffusivity,so the velocity decays slowly and high efficiency of rock breaking can be gained;the 45°orifice has largest radial velocity,tangential velocity and diffusivity,so the velocity seriously decays and large area rock can be broken with limited depth;the area of rock breaking of the three orifices covers each other,so when the nozzle swirls the rock breaking can be completed by the track scanning way;different inclination angle has different rock breaking rate,the 30°has the highest rate in this experiment.The simulation result is almost consistent with the experiment result.%设计了一种适用径向水平井技术的旋转射流多孔喷嘴。其前端面均布3个不同切向倾角15°、30°、45°的孔眼。利用数值模拟方法，采用 RNG k －ε湍流模型对该喷嘴流场特征进行了研究，并与试验破岩结果进行了对比。结果表明，15°孔眼轴向速度较大，扩散性差，衰减缓慢，类似直射流，破岩效果适中；30°孔眼轴向、径向、切向速度均较大，扩散性适中，衰减较慢，其破岩效果最佳；45°孔眼虽具有较高切向、径向速度，但扩散性较强，衰减较严重，可形成较大破岩面积，但破岩深度有限；3个孔眼破岩面积在径向存在重叠，当喷嘴旋转时，可轨道扫描式完成联合破岩；不同倾角破岩效果不同，本试验中30°倾角的孔眼破岩效果最佳。流场数值模拟结果与实际破岩效果基本一致。