Numerical study on particle-carrying ability of liquid nitrogen jet

ABSTRACT

Liquid nitrogen (LN₂) jet is expected to have the higher rock-breaking efficiency than water jet as its ultra-low temperature characteristic. It is considered that adding a few solid particles into LN₂ jet can noticeably enhance its rock-breaking capability. The abrasive LN₂ jet has a great application prospect in petroleum as well as geothermal exploitation. This study investigates the particle-carrying ability of LN₂ jet by a 3D numerical model. The geometric model adopts a spindle shape that is more similar to the realistic cavity created by abrasive jet. The standard $k-\epsilon$ model and discrete phase model are used to calculate the LN₂ flow and the particle trajectory, respectively. The Discrete Random Walk model is applied to describe the particle space movement in flow field. The results show that the particle in abrasive LN₂ jet obtains the highest nozzle exit velocity in simulation conditions, 11.1% higher than in water jet and 5.1% higher than in SC-CO₂ jet. The potential core of abrasive LN₂ jet is longest in these three types of abrasive jets. That means LN₂ jet has a well particle-carrying ability at high-speed state. However, the LN₂ turbulent flow at out-of-nozzle region causes the violent fluctuation of particle speed. Parametric analysis indicates that the nozzle pressure drop and nozzle diameter in LN₂ jet have the vital influences on particle velocity, while the ambient pressure and particle diameter affect particle velocity slightly. The simulation results reveal the particle-carrying ability of LN₂ jet in different conditions. It would shed light on cutting capability of abrasive LN₂ jet and promote its application in petroleum and geothermal exploitation.

KEYWORDS:

• particle-carrying ability
• liquid nitrogen
• abrasive jet
• rock breaking

Acknowledgments

The authors would like to acknowledge the National Key R&D Program of China (Grant No. 2021YFA0716004), National Science Fund for Distinguished Young Scholars (Grant No. 51725404).

Disclosure statement

No potential conflict of interest was reported by the author(s).