Effects of surface roughness on the heat transfer characteristics of water flow through a single granite fracture

The understanding of flow and heat transfer in a rough fracture is not sufficient at present due to the complexity of quantifying fracture geometry and the lack of experimental work. This paper adopted fractal dimension D and profile waviness Ra to characterize surface roughness and investigated the effects of surface roughness on the heat transfer characteristics of water flow through a single granite fracture by combining the experimental and numerical modeling approaches. It is found that the local heat transfer coefficient distribution mainly depends on the fracture surface roughness, followed by aperture and flow rate.