Thermal flow tests were conducted with 3D-printed fractures. We prepared an inlet beaker at room temperature and a heat bath with a heater set to 40°C. The fracture sample was connected with tubes to a pump, an inlet beaker full of water and an outlet beaker. Before running the flow experiments, the fracture model and flow tubes were saturated with water. We assume that the inlet temperature changes instantaneously to a constant injection temperature when injection commences. Cold water was injected into the fracture model with constant flow rates of 15, 20, 25, and 30 ml/min. Temperature changes were measured in the inlet beaker, at the fracture inlet, at the fracture outlet, and in the heat bath using K-type thermocouples.
