Modelling of Rock-Water Thermal Interaction in Different Scales

摘要

We study two analogous configurations of water flow in fractures in granite, with heat exchange between water and surrounding rock. The first case is a laboratory experiment on compact granite block 800×600×300 mm, where hot water is injected by a borehole into the artificial fracture oriented in the largest plane. The second case is a tunnel water inflow observation. The temperature in the tunnel changes quasi-periodicaly in the annual cycle. This causes thermal non-equilibrium between the blocks of compact rock and groundwater in the fractures which has temperature variations decreasing with flow rate. We show that both configurations can be described by the same conceptual model, with different problem size and input data. Simulations are done in the FEFLOW software. We can also partly interpret how the flow is distributed in the fracture plane or if it is present in a wider structure of crushed rock.