Experimental study of convective heat transfer characteristics of fractures with different morphologies based on fractal theory

Case Studies in Thermal Engineering

Yibin Huang¹  Yanjun Zhang²  Peng Zhang² 

[1] Engineering Research Center of Geothermal Resources Development Technology and Equipment, Ministry of Education, Jilin University, Changchun, 130026, China;College of Construction Engineering, Jilin University, Changchun, 130026, China;

关键词: Enhanced geothermal system(EGS);    Hot dry rock (HDR);    Heat transfer;    Overall heat transfer coefficient (OHTC);    Fractal theory;   

DOI  :  

来源: DOAJ

【 摘 要 】

In the Enhanced Geothermal System (EGS), the flow state of the fracture of the thermal reservoir (granite) is important for heat transfer. In this paper, the effects of reservoir temperature, flow rate and fracture shape on the thermal convection that occurs in the fracture of rough granite are studied based on the fractal dimension theory. The rough fracture is manufactured regularly by carving technology. The shear flow experiments were carried out at confining pressures of 10, 15 and 20 MPa to analyze the flow state. The convective heat transfer experiments were conducted at 60 and 70 °C to simulate different heat reservoir conditions. The results indicated that the outlet temperature and overall heat transfer coefficient (OHTC) increased with the increase in the rock temperature. A higher flow rate can enhance the thermal performance. The complexity of the fracture surface is also an important factor that affects the convective heat transfer process. The larger fractal dimension of the fracture surface can more easily excite turbulence, affecting the thickness of the boundary layer. The OHTC will increase as the fractal dimension increases.

【 授权许可】

Unknown