Analytical and experimental study of a reverse circulation drill bit with an annular slit
Analytical and experimental study of a reverse circulation drill bit with an annular slit
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环形缝反循环钻头的分析与实验研究
DOI：
10.1177/1687814016669471
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发表时间：
2016-09-01
影响因子：
2.1
通讯作者：
Wang, Jinsong
中科院分区：
文献类型：
--
作者：
Cao, Pinlu;Chen, Yunwang;Wang, Jinsong
为了提高潜孔锤钻进技术的反循环效果，研制了一种新型的环形缝钻头。使用计算流体动力学代码Fluent来模拟钻头内部的流动现象。模拟结果表明，通过环形缝的空气沿环形钻头中心通道壁面沿着向上运动，不存在与普通钻头类似的干涉现象，有利于反循环的形成。同时，研制了新型环缝钻头，并进行了实验室试验。结果表明，关闭冲洗喷嘴时，环形钻头吸入空气的质量流量约为63.78 g/s，是正常钻头吸入空气质量流量的1.76倍，而打开冲洗喷嘴时，吸入空气质量流量约为正常钻头吸入空气质量流量的2.46倍。此外，许多因素会影响环形钻头的反循环效果，包括狭缝宽度，环形狭缝与钻头工作表面之间的距离以及从环形狭缝喷出的气体的流动方向。
A new type of drill bit designed with an annular slit was developed to enhance the reverse circulation effect of the down-the-hole hammer drilling technology. A computational fluid dynamics code, Fluent, was used to simulate the flow phenomena inside the drill bit. The simulation results show that the air flowing through the annular slit moves upward along the wall of the central passage of the annular drill bit and that there is no interference phenomenon similar to the normal drill bit, which is beneficial for the formation of reverse circulation. Meanwhile, the new drill bit with the annular slit was produced and tested in the laboratory. The results show that for the annular drill bit with the flushing nozzles closed, the mass flow rate of the sucked air is approximately 63.78 g/s, which is 1.76 times that of the normal drill bit, while it is about 2.46 times if the flushing nozzles are opened. In addition, many factors can affect the reverse circulation effect of the annular drill bit, including the slit width, the distance between the annular slit and the working surface of the drill bit, and the flow direction of the gas ejected from the annular slit.