Investigation of heat transfer and damage characteristics of high pressure abrasive water jet impacting high temperature sandstone

ABSTRACT

Efficient breaking of hard mineral rocks is an important prerequisite for deep metal mining. In order to study the rock breaking mechanism of abrasive water jet erosion of high-temperature hard rock in deep ground, the temperature deformation evolution law during the process of jet impact on rocks was simulated and experimentally studied. The results show that the distribution of jet pressure, jet velocity, and jet turbulent kinetic energy near the residence point of the jet impingement wall is generally high in the middle and low in the outside. The heat transfer distance r on the rock surface is approximately (1.5–2.0) times the nozzle diameter, and the heat transfer distance inside the rock is (1.0–1.5) times the nozzle diameter. The maximum heat flux density at the jet cooling wetting boundary can reach 450 W/mm². Within 0–3 seconds of the erosion process, the average surface temperature sharply decreases and exhibits a downward trend of jet stagnation point radiating outward. The radius of jet cooling influence gradually increases. Due to the impact cooling effect, tensile stress is generated at the top of the rock sample, and the tensile stress in the lower part of the rock is converted into compressive stress. With the increase of jet pressure and treatment temperature, the area and range of erosion pits significantly increase, and there is a significant phenomenon of thermal cracking around the erosion pits. The research conclusion can provide new ideas and basis for hydraulic breaking of high-temperature hard rocks in deep ground.

KEYWORDS:

• Abrasive water jet
• high temperature rock
• fluid-thermo-structural coupling
• thermal transfer
• rock damage mechanisms

Highlights

• A new method of high pressure abrasive water jets coupled with thermal stress action to break high temperature hard rock is proposed.

• The heat transfer radius of jet erosion on the high-temperature rock surface is r= (1.5-2.0) times the nozzle outlet diameter, and the heat transfer radius inside the rock is r= (1.0-1.5) times the nozzle outlet diameter.

• During the initial stage of jet cooling impact on high-temperature sandstone, the surface temperature sharply decreases and radiates outward from the center.

• The extent of rock damage fragmentation increases with increasing jet pressure and temperature difference.

Acknowledgements

This work was supported by Open Research Fund of State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization, China Pingmei Shenma Group (Grant NO. 41040220171106-1). Furthermore, our deepest gratitude goes to the anonymous reviewers for their careful work and thoughtful suggestions that have helped improve this paper substantially.

Disclosure statement

No potential conflict of interest was reported by the authors.

Credit authorship contribution statement

Jianguo Zhang: Conceptualization, Methodology, Supervision.

Yingwei Wang: Conceptualization, Formal analysis, Writing- Reviewing and Editing.

Jianming Shangguan: Writing-original draft, Validation, Visualization, Investigation.

Zehua Niu: Resources, Data Curation

Rui Min: Data curation, Reviewing and Editing.

Statements and declarations

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

The work was supported by the Open Research Fund of State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization [NO. 41040220171106-1].

Notes on contributors

Jianguo Zhang

Jianguo Zhang, Professor level senior engineer, director of State key laboratory of coking coal exploitation and comprehensive utilization.

Yingwei Wang

Yingwei Wang, Researcher, Office director of State key laboratory of coking coal exploitation and comprehensive utilization.

Jianming Shangguan

Jianming Shangguan, Doctoral candidate at Chongqing University, Majoring in water jet rock breaking.

Zehua Niu

Zehua Niu, Laboratory staffs, State key laboratory of coking coal exploitation and comprehensive utilization.

Rui Min

Rui Min, Laboratory staffs, State key laboratory of coking coal exploitation and comprehensive utilization.