摘要
针对下向孔淹没水射流卸压增透技术的瓶颈问题,即冲击力弱、破煤效率低、冲割煤量少、适应性差等,提出了环空流体强化自激脉冲水射流下向孔破煤增透思想和原理,以破除孔底压持效应和水垫增阻效应,提高淹没状态水射流的冲击力和破煤效率。采用大涡模拟、打击力测试和冲击釜破煤实验等研究方法,研究了淹没条件下环空流体强化自激脉冲水射流的高效调制和破煤特性。首先建立了适用于煤矿下向孔增透的环空流体强化自激脉冲喷嘴物理模型,优化了喷嘴结构参数;然后研制了淹没脉冲射流高频打击力测试系统和环空流体强化自激脉冲水射流喷嘴,量化分析了环空流体强化自激脉冲喷嘴在淹没环境中的打击力和流场特性;最后研发了淹没水射流破煤实验系统,开展了淹没水射流破煤实验,揭示了环空流体强化自激脉冲水射流的破煤特性。研究结果表明:在煤矿下向孔工程条件下,由两侧带有自吸口的亥姆赫兹型自激脉冲喷嘴能够有效产生环空流体强化自激脉冲水射流,最优喷嘴结构参数为上喷嘴直径d1=3 mm、壁面碰撞角α=120°、下喷嘴直径d2=3.6 mm、振荡腔腔长L=10.5 mm、振荡腔腔径D=27 mm、引入口直径d3=4.2 mm,泵压为10 MPa时卷吸环空水量最大值为0.28 L/s,平均0.19 L/s;泵压相同时环空流体强化自激脉冲水射流与自激脉冲水射流主频相近,环空流体强化自激脉冲水射流的主频为253~285 Hz,而自激脉冲水射流的主频为251~282 Hz;环空流体强化自激脉冲水射流的峰值打击力分别为自激脉冲水射流、连续射流峰值打击力的1.05~1.08倍和1.63~1.89倍,平均打击力是自激脉冲水射流的1.09~1.16倍,反映了环空流体强化自激脉冲水射流在淹没状态下能够持续产生较大的打击力,具有良好的脉冲射流特性;相同泵压和靶距条件下,环空流体强化自激脉冲水射流比自激脉冲水射流、连续
There are some bottleneck problems in the pressure relief and antireflection technology of submerged water jet in a downward hole,such as weak impact force,low coal breaking efficiency,less coal cutting and poor adaptability.In this study,the idea and principle of coal breaking and antireflection of self-excited pulsed water jet in downward hole strengthened by the annular fluid were put forward in order to break the pressure holding effect at the bottom of the hole and the drag increase effect of water cushion,and improve the impact force and coal breaking efficiency of the submerged water jet.The high-efficiency modulation and coal-breaking characteristics of self-excited pulsed water jet enhanced by annular fluid were studied by using large eddy simulation,impact force test and impact kettle coal breaking experiment.Firstly,the physical model of an annular fluid-enhanced self-excited pulse nozzle suitable for the anti-reflection of downward holes in coal mines was established,and the nozzle structure parameters were optimized.Then a high-frequency impact force test system of a submerged pulsed jet and annular fluid-enhanced self-excited pulsed water jet nozzle was developed,and the impact force and flow field characteristics of the annular fluid-enhanced self-excited pulsed nozzle in the submerged environment were quantitatively analyzed.Finally,the coal breaking experiment system of submerged water jet was developed,and the coal breaking experiment of submerged water jet was carried out,which revealed the coal breaking characteristics of the annular fluid-enhanced self-excited pulsed water jet.The results show that under the engineering condition of a down-hole in the coal mines,the self-excited pulse water jet enhanced by annulus fluid can be effectively generated by the self-excited pulse nozzle with self-priming Helmholtz resonance cavity structure on both sides.The optimal nozzle structure parameters are as follows:the diameter of the upper nozzle d1=3 mm,the angle of collapse wallα=120°,the diameter of
作者
刘彦伟
龙丽群
左伟芹
李怀珍
韩红凯
史进
李运强
苗健
贾浩杰
LIU Yanwei;LONG Liqun;ZUO Weiqin;LI Huaizhen;HAN Hongkai;SHI Jin;LI Yunqiang;MIAO Jian;JIA Haojie(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Henan International Joint Laboratory of Coal Mine Safety and Occupational Hazards Prevention and Control,Jiaozuo 454000,China;College of Literature,Science,and the Arts,University of Michigan,Ann Arbor,Michigan 48109,United Sates;School of Intelligent Engineering,Shandong Management University,Jinan 250357,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2023年第9期3393-3404,共12页
Journal of China Coal Society
基金
国家自然科学基金资助项目(52174173,52274188)
中国工程科技发展战略河南研究院战略咨询研究资助项目(2023HENZDB05)。
关键词
自激脉冲射流
喷嘴结构
卸压增透
流场特性测试
破煤实验
self-excited pulsed jet
nozzle structure
pressure relief and antireflection
flow field characteristics test
coal breaking experiment
