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磨料水射流旋转切割煤岩最优参数匹配模型研究

Study on the optimal parameter matching model of rotary cutting coal-rock for abrasive water jet

  • 摘要: 随着煤炭开采向深部延伸,纯水射流技术已逐渐无法满足高地应力和高煤岩强度条件下破煤增透需求。磨料水射流能有效提高水射流破岩能力,磨料水射流旋转切割卸压技术可实现高地应力、坚硬煤层的高效增透。射流压力和旋转速度是影响磨料水射流旋转切割煤岩效果的重要因素,明确磨料水射流旋转切割硬煤力学特征及规律是合理匹配射流压力和旋转速度的前提。采用数值模拟和实验研究相结合的方法,分析了不同射流压力和旋转速度匹配关系对射流冲击靶体力学作用机制的影响,明确了不同射流压力和旋转速度对磨料水射流旋转割缝效果的影响规律。研究结果表明,磨料颗粒高速撞击煤岩产生的法向力主要取决于射流压力,而切向力则同时取决于射流压力和旋转速度,法向力和切向力在磨料颗粒冲击破煤过程中作用不同,两者共同决定了磨料水射流旋转切割煤岩效果;当射流压力小于25 MPa时,割缝深度随射流压力升高而增加,超过25 MPa后割缝深度增加速率显著降低;在割缝时间恒定条件下,磨料射流旋转切割深度随转速的增加始终呈上升趋势;提出以最优匹配系数n作为同一射流压力下不同转速切割效果的评判指标,发现不同工况条件下淹没与非淹没条件下的n值存在显著差异,当前研究条件下非淹工况最优参数匹配系数n为0.002 015 6,淹没工况最优参数匹配系数为0.000 299;建立了磨料水射流旋转割缝射流压力和旋转速度最优匹配参数计算模型,可根据射流压力直接计算得到最优匹配转速,使射流切割效果最优。

     

    Abstract: As coal mining extends deeper, pure water jet technology is gradually unable to meet the demand for coal penetration enhancement under high stress and high coal rock strength conditions. Abrasive water jet can effectively improve the rock breaking ability of water jet, and the abrasive water jet rotary cutting pressure relief technology can achieve efficient anti permeability of high stress and hard coal seams. Jet pressure and rotation speed are important factors affecting the effectiveness of abrasive water jet rotary cutting of coal and rock. Clarifying the mechanical characteristics and laws of abrasive water jet rotary cutting of hard coal is a prerequisite for reasonably matching jet pressure and rotation speed. This article adopts a combination of numerical simulation and experimental research to analyze the influence of different jet pressure and rotation speed matching relationships on the mechanical mechanism of jet impact on the target body, and clarify the influence rules of different jet pressure and rotation speed on the cutting effect of abrasive water jet rotation. The research results indicate that the normal force generated by the high-speed impact of abrasive particles on coal and rock mainly depends on the jet pressure, while the tangential force depends on both the jet pressure and the rotational speed. The normal force and tangential force have different effects on the impact of abrasive particles on coal breaking, and together determine the effect of abrasive water jet rotation cutting coal and rock. When the jet pressure is less than 25 MPa, the cutting depth increases with the increase of jet pressure, and the rate of increase in cutting depth significantly decreases after exceeding 25 MPa. Under the condition of constant cutting time, the cutting depth of abrasive jet rotation always shows an upward trend with the increase of rotation speed. Propose to use the optimal matching coefficient n as the evaluation index for cutting effects at different speeds under the same jet pressure. It was found that there were significant differences in the value of n between submerged and non submerged conditions under different working conditions. The optimal parameter matching coefficient n for non submerged conditions is 0.0020156, while for submerged conditions it is 0.000299. A calculation model for the optimal matching parameters of abrasive water jet rotating slotting jet pressure and rotation speed has been established. The optimal matching speed can be directly calculated based on the jet pressure, resulting in the best jet cutting effect.

     

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