Heat Transfer from the Hot Rock to Water Flowing through Crack

Abstract

Heat transfer between fluid flowing in a slit and particles packed in it and that between the fluid and the slit wall are important for the extraction of heat from the hot dry rock. Mass transfer coefficients, instead of the heat transfer coefficients, on the packed particles in the slit and on the slit wall were measured by making use of the electrochemical method. The result indicates that the mass transfer coefficient on the particles increases with decreasing void fraction and approaches to that in the usual packed bed. The mass transfer coefficient at the wall increases also with decreasing void fraction. New empirical equations for the mass transfer coefficients on the packed particles in the slit and on the slit wall are presented.