Abstract

In order to optimize the parameters of pre-mixed abrasive water jet cutting technology, make it more efficient in the coal mine gas environment and solve the problem of hard coal and the difficulty of rock drilling, FLUENT software was used to get the isothermal, incompressible, steady flow field out of a submerged abrasive water jet nozzle through numerical simulation, with different particle sizes and different confining pressures under submerged conditions. The results show that, under submerged conditions, the maximum velocity of the abrasive particle outside the pre-mixed abrasive water jet nozzle is about 6 mm far away from the nozzle; the abrasive particle diameter has little influence on the velocity outside the nozzle. The external confining pressure of the nozzle has an important influence on the velocity, which is that the jet velocity of the same position decreases with the increase of confining pressure and the relationship between the confining pressure of different distance from the nozzle exit and the abrasive velocity is exponential function. The results of the simulation laid the foundation for optimizing the nozzle structure, improving efficiency and developing the abrasive water jet nozzle.

Highlights

  • Abrasive water jet (AWJ) cutting is closely related to safety engineering [1,2]

  • The pre-mixed abrasive water jet that helps in drilling and the coal slotted relief adopted in the field of coal are efficient technical methods for improving the pre-pumping effect of low permeability coal seam gas

  • The flow field out of the submerged abrasive water jet nozzle is a kind of typical turbulent two-phase flow with liquid and solid

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Summary

Introduction

Abrasive water jet (AWJ) cutting is closely related to safety engineering [1,2]. AWJ cutting is the “cold cutting” that cannot produce heat during the cutting process, so it is fit for the work of cutting in flammable and explosive environments for safety. The method of abrasive water jet breaking of coal and rock was studied by Li [3]. The technology and equipment for high-pressure abrasive jet cutting, drilling and penetration enhancing were studied and applied in Ping Ding Shan Coal Group by Lin [5]. The flow field out of the submerged abrasive water jet nozzle is a kind of typical turbulent two-phase flow with liquid and solid. PHOENICS software was used to simulate the distribution of the flow field of submerged abrasive jets in deep water by Gao Jifei et al [12]. The liquid-solid two-phase flow field out of the submerged abrasive water jet nozzle will be simulated using the numerical simulation method. The achievements can provide the basis for optimizing AWJ cutting equipment in mines

Mathematical Model
Main Assumptions
Standard Kε Turbulence Equations
Geometrical Model
Physical
Boundary
Results
The influence of abrasive particle diameter on the
Influence
The Influence of Confining Pressure on the Jet Flow Field
13. Fitting
Conclusions
Full Text
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