【摘要】 水力割缝技术作为有效的煤层增透措施之一，在地应力作用下割缝空间排布和角度对割缝效果影响显著，但常规割缝器由于其自身结构局限性在现场施工时缝槽角度不可调节，难以实现最优的割缝空间排布和角度。研制了一种新型煤层定向水力割缝器，其关键定向功能由角度调节机构与可活动喷嘴机构实现，利用钻杆旋转运动周期性改变喷嘴角度，实现定向割缝，改变缝槽角度。对角度调节机构进行了运动分析，当r为18 mm时，可调节角度为17.7°。通过与常规割缝器对比开展流场试验和破岩试验，研究其射流扩散角、打击力、破岩能力等性能。试验结果表明，定向割缝器在一定程度上能控制射流扩散，在较高压力下仍可保持较集中射流形态，且其射流扩散角受软管状态影响显著，自然伸直状态时最小；定向割缝器在相同条件下打击力高于常规割缝器，且与其流场特性紧密相关；定向割缝器在不减少切割能力的前提下改变了割缝角度，割缝深度提升30.87%,且破岩特性也对应其流场及打击力特性；煤层定向水力割缝器的研制为解决常规割缝器的不足提供了有效途径，有助于提高煤层瓦斯抽采效率和矿井安全生产水平。更多还原

【Abstract】 Hydraulic slotting technology is an effective method for enhancing the permeability of coal seams. The spatial arrangement and angle of the slotting process significantly influence its effectiveness under in-situ stress conditions. However, conventional slotters have structural limitations, preventing the adjustment of the slot angle during field operations, which makes it difficult to achieve optimal slotting geometry. A new type of directional hydraulic slotter for coal seams was developed, whose directional functionality was enabled by an angle regulator and a movable nozzle mechanism. The rotary motion of the drill pipe periodically adjusted the nozzle angle, allowing directional slotting and modification of the slot angle. A motion analysis of the angle adjustment mechanism was also presented, showing that when the radius r is 18 mm, the adjustable angle reaches 17.7°. Comparative flow field and rock-breaking experiments were conducted to evaluate the performances of jet diffusion angle, impact force, and rock-breaking efficiency. The results indicate that the directional slotter can control jet diffusion to some extent, maintaining still a relatively focused jet pattern under high pressure. The jet diffusion angle is significantly influenced by the hose configuration, being smallest when the hose is in its natural extension state. Under similar conditions, the impact force of the directional slotter exceeds that of the conventional slotter, which correlates closely with its flow field characteristics. The directional slotter is capable of adjusting the slot angle without compromising its slotting efficiency. Furthermore, the cutting depth is increased by 30.87%, and the rock-breaking characteristics are consistent with the flow field and impact force behaviors. The development of the coal seam directional hydraulic slotter offers an effective solution to the limitation of conventional slotters, ultimately enhancing coal seam gas extraction efficiency and improving mine safety.更多还原