In view of the research deficiencies in the flow field characteristics and rock-breaking and hole-forming mechanism of the multi-hole rotating jet bit for water jet radial drilling in underground coal mines, numerical simulation and indoor experiments were carried out. By using the RNG k-ε turbulence model to simulate and analyze the flow field characteristics of the forward nozzle of the multi-hole rotating jet bit, the results show that at the same bottom hole surface, the jet velocity and pressure gradually decrease with the increase of the spray distance, and the axial velocity of the nozzle jet shows the same attenuation law with the increase of the spray distance. The axial velocity of the 20° and 30° nozzle jets is larger and decays more slowly, while the 50° nozzle jet has a larger radial velocity, and the combined effect achieves axial and radial impact rock-breaking and hole-forming drilling and hole diameter expansion. The velocity and pressure of the forward nozzle jet at different spray distances show a peak distribution, and as the spray distance and nozzle angle increase, the corresponding lateral radius and jet area of the peak point gradually increase. Using the laboratory high-pressure water jet rock-breaking and drilling test system, the dynamic process of rock-breaking and hole-forming and the hole-forming effect were analyzed by using homogeneous sandstone and anisotropic raw coal specimens. The results show that under the rotation effect, the forward nozzles with different angles achieve scanning rock-breaking along their respective tracks, forming inner, middle and outer ring fracture zones, and the sandstone is progressively broken and a hole is formed as the nozzle advances, resulting in a regular circular cross-section hole. Further comparison of the hole-forming effects of the sandstone and raw coal specimens shows that the hole diameters are 24 mm and 38 mm respectively, and the hole-forming effects are good, basically meeting the requirements of water jet radial drilling in underground coal mines, providing a reference basis for the subsequent optimization of the structural parameters of the multi-hole rotating jet bit.
BA Quan-bin, LIU Yan-bao.
Flow Field Characteristics and Dynamic Rock-breaking Progress of Multi-hole Rotating Jet Bit[J].
Science Technology and Engineering, 2026, 26(9): 3705-3714 DOI:10.12404/j.issn.1671-1815.2503183
HuangZhongwei, LiGuofu, YangRuiyue. Review and development trends of coalbed methane exploitation technology in China[J]. Journal of China Coal Society, 2022, 47(9): 3212-3238.
WangZhengshuai. Gas flow law of broken soft and difficult desorption coal seams in ewirgol mining area[J]. Science Technology and Engineering, 2023, 23(32): 13781-13787.
XuFengyin, ZhenHuaibin, LiShuguang, et al. The history and development direction of iterative upgrading of deep coalbed methane reservoir reconstruction technology: taking the Daji Block in the eastern margin of the Ordos Basin as an example[J]. Coal Science and Technology, 2025, 53(3): 1-18.
[7]
XiaoS, RenQ, GeZ, et al. Study of the rock-breaking and drilling performance of a self-rotatory water-jet bit in water-jet drilling and its influential factors[J]. Energy Sources Part A Recovery Utilization and Environmental Effects, 2020(6): 8614-8631.
LuYiyu, HuangShan, GeZhaolong, et al. Research progress and strategic thinking of coal mine water jet technology to enhance coal permeability in China[J]. Journal of China Coal Society, 2022, 47(9): 3189-3211.
[10]
孙庆斌. 基于水射流的自进式喷头设计及试验探究[D]. 淮南: 安徽理工大学, 2021.
[11]
SunQingbin. The design and experiment of self-advancing sprinkler based on water jet[D]. Huainan: Anhui University of Science and Technology, 2021.
ZhangQun, JiangWenping, JiangZaibing, et al. Present situation and technical research progress of coalbed methane surface development in coal mining areas of China[J]. Coal Geology & Exploration, 2023, 51(1): 139-158.
XianBaoan, GaoDeli, XuFengyin, et al. Research progress of coalbed methane horizontal well drilling and completion technology in China[J]. Acta Petrolei Sinica, 2023, 44(11): 1974-1992.
GaoDeli, BiYansen, XianBaoan. Technical advances in well types and drilling & completion for high-efficient development of coalbed methane in China[J]. Natural Gas Industry, 2022, 42(6): 1-18.
HuQiangfa, GuZiang, FangWei, et al. Optimization of hydraulic parameters and structure parameters of rotary jetting tools[J]. Oil Drilling & Production Technology, 2022, 44(3): 366-375.
[26]
夏维康. 自旋转射流流场及破碎煤岩特性研究[D]. 淮南: 安徽理工大学, 2022.
[27]
XiaWeikang. Study on flow field of self-rotating jet and characteristics of broken coal and rock[D]. Huainan: Anhui University of Science and Technology, 2022.
ZhaoJin, ZhaoXing, CaiPeng, et al. Development of coiled tubing jet tools with multi-hole nozzles and cleaning parameter optimization[J]. Petroleum Drilling Techniques, 2023, 51(3): 83-89.
[30]
吕前. 多孔射流喷嘴流量系数分析及其结构优化研究[D]. 徐州: 中国矿业大学, 2023.
[31]
LüQian. Flow coefficient analysis of multi-orifice jet nozzle and its structure optimization[D]. Xuzhou: Chian University of Mining and Technology, 2023.
[32]
LiuY, HeL, DaiL, et al. Analysis of rock breaking parameters and simulation of mechanical characteristics of multi-nozzle jet impact[J]. Sustainability, 2023, 15: 1-20.
[33]
戴兴茹. 径向水平井射流钻头自进能力及其参数优化研究[D]. 徐州: 中国矿业大学, 2023.
[34]
DaiXingru. Study on the self-propelled capability of radial horizontal well water jet drill bit and its parameter optimization[D]. Xuzhou: China University of Mining and Technology, 2023.
XuYayou, TianJiakuo, DaiXingru, et al. Optimization of front-end structural parameters of radial water jet bit based on FLUENT numerical simulation[J]. Mining Research and Development, 2024, 44(12): 212-220.
[37]
徐宝兴. 直旋混合射流形成机理与冲蚀岩石特性研究[D]. 淮南: 安徽理工大学, 2024.
[38]
XuBaoxing. Study on the formation mechanism of the straight spiral mixed jet and the characteristics of the erosion rock[D]. Huainan: Anhui University of Science and Technology, 2024.
ZhaoWentao, ChenZhengshou, ChenYuanjie, et al. Research on spatial layout optimization of ultra-high-pressure water jet self-driven rotary sprayer[J]. China Mechanical Engineering, 1-14[2025-12-31]. https://kns.cnki.net/kcms/detail/42.1294.TH.20250829.1338.002.html.
WeiZhidong. Research on the structural design of hydraulic self-rotating multi-hole jet drill bit and the characteristics of breaking coal rock[D]. Huainan: Anhui University of Science and Technology, 2024.
JiZhaosheng. Study on nozzle structure optimization considering rheological characteristics of real drilling fluid[J]. Oil Field Equipment, 2025, 54(5): 16-23.
WangYan, ShiJinlong, ZhangDongsu, et al. Structural design and analysis of water jet/abrasive water jet composite self-propelled drilling device[J]. Coal Science and Technology, 1-11[2025-12-31]. https://kns.cnki.net/kcms/detail/11.2402.TD.20250923.1001.004.html.
LinBaiquan, YangWei, LiuTong. Typical characteristics of deep coal seams with high outburst risk, outburst inducing mechanism and prevention measures[J]. Journal of China Coal Society, 2025, 50(1): 311-325.
LiuZegong, QiaoGuodong, LiuJian, et al. Research progress and prospect of coal seam blasting antireflection technology in China[J]. Journal of China Coal Society, 2025, 50(5): 2453-2476.
LiuYanbao, LeiZhenjie, ChenKun, et al. Study on striking force characteristics of hydraulic jet self-drilling multi-hole nozzle[J]. Minging Safety & Environmental Protection, 2024, 51(4): 49-55.
ZhanKai, ZhangSi, TangWei, et al. Numerical simulation of rock breaking flow field by gas-liquid two-phase jet[J]. Science Technology and Engineering, 2022, 22(23): 10034-10041.
YangXinxia, YanYuejuan, XuYan, et al. Impact analysis of turbulence models on numerical simulation of cavitating jet from organ pipe nozzle[J]. Science Technology and Engineering, 2024, 24(15): 6346-6353.