复杂地层用反循环钻头双排内喷孔结构优化与试验

Structural Optimization and Test of Double Row Suction Nozzles for Reverse Circulation Drill Bits Used in Complex Formations

采用正交试验和计算流体动力学相结合的方法,对矿山多层空区钻探用150 mm反循环钻头双排内喷孔的4个结构参数进行优化分析,分析结构参数变化对钻头抽吸量Q的影响规律,并最终得出这4个结构参数的主次排序依次为:倾角(θs)、水平偏角(θd)、垂直间距(L)、水平间距(S).最优参数组合为:θs=30°,θd=10°,L=-15 mm和S=10 mm.与此同时,将最优参数组合下的150 mm反循环钻头进行多层空区探测孔钻进试验.从钻进试验效果看,穿过第一层空区继续实现反循环钻进,钻头依然能够形成良好的反循环抽吸效果,并且连续不断排出大颗粒岩块,解决矿山多层空区钻探及测量难题.

The 4 main structural parameters of double row suction nozzles for 150 mm reverse circulation drill bits used in multilayer goaf drilling were optimized by orthogonal design method and CFD（ computational fluid dynamics） analysis. The analysis results indicated the primary and secondary orders as follows： the inclination angle （θs）, the horizontal deflection angle （θd）, the vertical space （L） and the horizontal space （S）, with the most optimal parameter combination being θs=30°,θd=10°, L = - 15 mm and S = 10 ram. At the same time, the 150 mm reverse circulation drill bit which adopts the most optimal parameter combination was carded on the multilayer goal drilling test. The test results showed that the reverse circulation drilling can still be achieved through the first layer goaf, and the rock sample with large particles can be continuously discharged from the borehole bottom to the earth surface. The problem on multilayer goaf drilling and measurement in mines can thus be resolved.