Experimental study and numerical simulation of water-sand two-phase flow in fracture network

ABSTRACT

The flow characteristics of water-sand two-phase in fractured rock mass has an important influence on underground engineering. A series of laboratory experiments are carried out by using a self-made fracture network test system. Based on the Euler-Lagrange method, a numerical simulation study of water-sand two-phase flow is conducted. The effects of sand mass fraction w, sand particle size Φ and combination of inlet and outlet on the flow characteristics of water-sand are systematically analyzed. The results show that the water-sand outflow is directly proportional to the fracture openings, and the growth rate of water-sand outflow is significantly different under multiple inlet-outlets configurations. The final volume proportions of water-sand are 14.1%, 35.9% and 50% respectively. Fluidity I exhibits an inverse correlation with fracture opening, w and Φ. Under the condition of the single inlet and outlet, the minimum fluidity I for 0.6 mm opening is 3.28E–7 m²⁺ⁿs^2-n/kg, the maximum fluidity I for 2.0 mm opening, reaching 3.88E–6 m²⁺ⁿs^2-n/kg. Based on the response surface regression method, a multivariate regression model for three fracture openings was established, boasting exceptional predictive accuracy and reliability. Particle residence time correlates positively with w and Φ. The turbulent kinetic energy k is significantly affected by the fracture opening and decreases with the increase of w and Φ. The variation range of k is 0.38 m²/s² ~0.63 m²/s². The results deepen our understanding of the migration behavior of water-sand in the fracture network, and provide a theoretical guidance for groundwater resource protection and other underground engineering.

KEYWORDS:

• Water-sand
• two-phase flow
• multiple regression model
• turbulent kinetic energy
• underground engineering

Disclosure statement

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

Data availability statement

The data used to support the findings of this study are available from the corresponding author upon request.

Additional information

Funding

This research was funded by the National Natural Science Foundation of China [52034007] and the Postgraduate Research & Practice Innovation Program of Jiangsu Province [KYCX22_2843].

Notes on contributors

Wei Li

Wei Li Master in School of mechatronic Engineering, Jiangsu Normal University. His research interests mainly about fluid mechanics and seepage in fractured rock.

Shengzhou Feng

Shengzhou Feng Master in Suzhou University of Science and Technology. His research interests mainly about surface Strengthening for 3d Printing.

Yu Liu

Yu Liu Vice professor in School of mechatronic Engineering, Jiangsu Normal University. He received the B.Sc.degrees in Jiangsu Ocean University, Lianyungang, China. He received the M.Sc. and Ph.D. degrees in mining engineering from the CUMT, Xuzhou, China, in 2004 and 2014, respectively. His research interests mainly about seepage of broken rock and fracture.

Shuncai Li

Shuncai Li Professor in School of mechatronic Engineering, Jiangsu Normal University. She received the B.Sc.degrees in Chongqing University, Chongqing, China. She received the M.Sc. and Ph.D. degrees in mining engineering from the CUMT, Xuzhou, China, in 2004 and 2014, respectively. Her research interests mainly about seepage of broken rock and fracture.

Liqiang Ma

Liqiang Ma Professor in school of Mining Engineering, China University of Mining and Technology. His research interests mainly about mine pressure and formation control, water retention mining and green mining.

Lei Yue

Lei Yue Master in School of mechatronic Engineering, Jiangsu Normal University. His research interests mainly about seepage from filled rock.

Jintao Wang

Jintao Wang Master in School of mechatronic Engineering, Jiangsu Normal University. His research interests mainly about microscopic seepage in fractured rock.