高压水射流煤层割缝深度数值模拟与实验研究  

Numerical simulation and experimental study on the depth of coal seamslotting by high pressure water jets

作　　者：刘德成 赵伟 贾林林 王涛 夏代林 刘勇[3] Liu Decheng;Zhao Wei;Jia Linlin;Wang Tao;Xia Dailin;Liu Yong(Henan Longyu Energy Co.,Ltd.,Yongcheng 476600,China;Wuhan Tianchen Weiye Geophysical Technology Co.,Ltd.,Wuhan 430205,China;College of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China)

机构地区：[1]河南龙宇能源股份有限公司,河南永城476600 [2]武汉天宸伟业物探科技有限公司,湖北武汉430205 [3]河南理工大学安全科学与工程学院,河南焦作454000

出　　处：《能源与环保》2023年第10期16-24,共9页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：国家自然科学基金项目(52174170,52374192);河南省高校科技创新人才项目(21HASTIT009)。

摘　　要：高压水射流割缝技术是提高低透气性煤层瓦斯抽采效率的有效措施之一,确定割缝深度是优化钻孔布置和射流参数的基础。基于Fluent软件数值模拟分析了入口压力、靶距、旋转速度对水射流流场特征的影响规律;基于高压水射流破煤实验系统,开展了淹没和非淹没条件下冲击破煤实验,并进行了现场实验。研究表明,喷嘴结构一定时,水射流速度随着入口压力的增大而增加,冲击压力随冲击距离增大而发生衰减;水射流发展过程中截面积逐渐增大,导致冲击压力集中区域的范围随靶距的增大而逐渐扩展;射流旋转会导致旋转方向一侧的应力大于另一侧,靶体表面最大切应力随旋转速度增加而增大;随着入口压力和冲蚀时间的增加,水射流对试样的冲蚀深度增大,但冲蚀深度随冲蚀时间的增加存在阈值。根据高压水射流破煤深度实验结果可知,喷嘴直径为1 mm、压力为30 MPa时,水射流割缝直径可以达到1.2 m。工程应用表明,割缝钻孔平均瓦斯抽采流量为普通钻孔的1.56~2.52倍;抽采16 d后,瓦斯抽采浓度维持在30%以上。The high pressure water jet slotting technique is one of the effective measures to improve the efficiency of gas extraction from low permeability coal seams.Determining the slotting depth is the basis for optimizing the borehole arrangement and jet parameters.In this paper,the influence law of inlet pressure,target distance and rotation speed on the flow field characteristics of water jets were analyzed numerically based on Fluent.The impact coal breaking experiments under submerged and non-submerged conditions were carried out based on the high pressure water jet coal breaking experimental system,and field experiments were conducted.The following conclusions is formed:when the nozzle structure is certain,the water jet velocity increases with the increase of inlet pressure,and the impact pressure decays with the increase of impact distance.The cross-sectional area gradually increases during the development of the water jet,resulting in a gradual expansion of the range of the impact pressure concentration area with increasing target distance.The rotation of the jet causes the stress on one side of the rotation direction to be greater than the other,and the maximum tangential stress on the target surface increases with the speed of rotation.As the inlet pressure and erosion time increase,the depth of erosion of the water jet on the specimen increases,but there is a threshold value for the depth of erosion with increasing erosion time.According to the experimental results of high pressure water jet coal breaking depth,the diameter of water jet slotting can reach 1.2 m when the nozzle diameter is 1 mm and the pressure is 30 MPa.Engineering application data shows that the average gas extraction flow rate of slotting boreholes is 1.56~2.52 times of the average gas extraction flow rate of ordinary boreholes;after 16 days of extraction,the gas concentration is maintained above 30%.

关 键 词：水射流 冲击压力 割缝深度 抽采流量 瓦斯浓度 

分 类 号：TD712.62[矿业工程—矿井通风与安全]