Scholarlink

<p>This study presents a pioneering experimental investigation of a cryogenic ice air jet (IAJ) system utilizing a Laval nozzle for coal breakage, aimed at enhancing underground roadway pressure relief and permeability in coal mines. By replacing conventional solid abrasives with clean, brittle ice particles accelerated by compressed air, the IAJ technique forms a high-velocity multiphase jet that minimizes dust generation and eliminates residual abrasive contamination. Experimental results demonstrated that stable, cone-shaped cavities were consistently formed across coals of varying maturity and jetting orientations relative to bedding. Notably, jetting perpendicular to bedding increased erosion volume by up to 60.1% compared to parallel jetting. Computed tomography analysis confirmed the creation of connected fractures, significantly enhancing the connectivity within the coal matrix. Mechanistic interpretation revealed that coal breakage is governed by coupled effects of localized dynamic impact, cryogenic embrittlement, and secondary fragmentation erosion. Sensitivity analysis identified jetting pressure, exposure time, and nozzle throat diameter as dominant control factors influencing erosion characteristics. Based on experimental optimization, an operational configuration of 0.5&#xa0;MPa jetting pressure, 8–9&#xa0;mm nozzle throat diameter, a dimensionless standoff distance of 8–14, and jetting perpendicular to bedding is recommended. Overall, this study confirms the IAJ as a promising green and adaptable technology for safe and efficient coal seam modification. Its low-pressure operation and clean abrasive medium offer distinct environmental advantages over conventional clean jetting methods, supporting its application in underground pressure relief and permeability enhancement operations in coal mining.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Development and Experimental Validation of an Ice Air Jet with a Laval Nozzle for Coal Breakage and Permeability Enhancement

  • 期刊论文

  • 发表日期：

    2025年12月27日

查看全文
  • Jingru Hu,
  • Hou Zhong,
  • Kang Cheng,
  • Shihao Zhang,
  • Bing Xi,
  • Huan Li,
  • Gensheng Li,
  • Jingbin Li,
  • Zhongwei Huang,
  • Ke Hu

摘要

This study presents a pioneering experimental investigation of a cryogenic ice air jet (IAJ) system utilizing a Laval nozzle for coal breakage, aimed at enhancing underground roadway pressure relief and permeability in coal mines. By replacing conventional solid abrasives with clean, brittle ice particles accelerated by compressed air, the IAJ technique forms a high-velocity multiphase jet that minimizes dust generation and eliminates residual abrasive contamination. Experimental results demonstrated that stable, cone-shaped cavities were consistently formed across coals of varying maturity and jetting orientations relative to bedding. Notably, jetting perpendicular to bedding increased erosion volume by up to 60.1% compared to parallel jetting. Computed tomography analysis confirmed the creation of connected fractures, significantly enhancing the connectivity within the coal matrix. Mechanistic interpretation revealed that coal breakage is governed by coupled effects of localized dynamic impact, cryogenic embrittlement, and secondary fragmentation erosion. Sensitivity analysis identified jetting pressure, exposure time, and nozzle throat diameter as dominant control factors influencing erosion characteristics. Based on experimental optimization, an operational configuration of 0.5 MPa jetting pressure, 8–9 mm nozzle throat diameter, a dimensionless standoff distance of 8–14, and jetting perpendicular to bedding is recommended. Overall, this study confirms the IAJ as a promising green and adaptable technology for safe and efficient coal seam modification. Its low-pressure operation and clean abrasive medium offer distinct environmental advantages over conventional clean jetting methods, supporting its application in underground pressure relief and permeability enhancement operations in coal mining.