Heat transfer from hot dry rock to waterflowingthrough a circular fracture

Surface averaged mass transfer coe.cients on the wall of two circular disks between which spherical particles are randomly packed and the ~uid ~owed two!dimensionally from the inlet to the outlet were measured by means of the electrochemical method[ The measured average mass transfer coe.cients agreed with the calculated values\ which were obtained by integrating the local mass transfer coe.cient[ Numerical simulation on heat transfer from the hot dry rock to ~owing water in the circular fracture was performed by using the local heat transfer coe.cients[ The local heat transfer coe.cients were obtained from the analogy between heat and mass transfers\ in which the di}erence between the boundary condition for the heat transfer and that for the mass transfer in the laminar ~ow through the slit was taken into account[ The result of the numerical simulation indicates that the forced convection between ~owing water and the fracture surface has an important role in the heat transfer mechanism only in the early stage of heat extraction and the assumption that the temperature of the ~owing water is equal to that of the fracture wall is\ in practice\ valid for the estimation of the water temperature at the production well[ 0888 CNR[ Published by Elsevier Science Ltd[