水力喷射多孔旋转喷头流场特性及关键参数优化研究
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中图分类号：TD713 文献标志码：A
Abstract：Limited by the confined spaces and complex coal and rock conditions in underground mines， hydraulic jetdriling requires smalernozzles to create larger hole diameters.Thisstudy focused onoptimizing the keylayout parameters forthe forward nozzles，considering theoffset layoutofforwardand backward nozzles ona multi-hole rotating nozleand thecharacteristicsofthejet action.Anumericalsimulationandanalysisof the flow field characteristics of the forward nozzles was conducted using the RNG k -εturbulence model. The results indicated thatthe jets fromthe innerand middlering nozzles exhibited higheraxial velocities，whereas the jets fromtheouter ring nozzle hada higherradial velocity.As theangleand distanceofthe nozzles increased relative totheaxisofthe multi-holerotating nozle，theoverlappingareaofthecrushingrings formedbythe jets fromthe innerand middle ring nozzles on their respective rotating trajectories progressively decreased，，suggesting a weakening of the mutual interference between these jets.Laboratory high-pressure water jet experiments were conducted on sandstoneandraw coal specimens to break coal and rock.Theexperimental results demonstrated that when theangles ofthe inner，middle，and outer ring nozzles relativeto the axisofthe rotating nozzle were 20∘ ， 30∘ and 50∘ ，respectively，and the distancesof the middle and outer ring nozzles from the axis were 2mm （20 and 5mm ，respectively， the multi-hole rotating nozzle achieved a hole diameter of 24mm with a regular circular cross-section in sandstone specimens and a diameter of 38mm in raw coal specimens. These outcomes substantially satisfy the performance requirements for hole formation in hydraulic jet driling.
Key words： hydraulic jet; multi-hole rotating nozze;nozzle；high-pressure water jet；flow field characteristics; hole formation in coal and rock
0引言
煤矿井下水力喷射小曲率径向分支孔钻进技术是一种新型的煤层增透技术，其源于石油天然气钻采行业超短半径径向水平井[1-3]，是以高压水为动力，利用水力喷射钻进喷头在煤层中钻进，并在导向装置的引导下钻出呈放射状或羽扇状孔群，可实现沿主钻孔钻出多个分支孔，有效增大煤层暴露面积，提高煤层透气性和煤层气产量[4-6]。（剩余9797字）
