摘要
Abstract: Owing to the shortage of traditional fossil energy, at present the use of geothermal energy has aroused people considerable attention. As a kind of clean and renewable geothermal resource, the hot dry rock will be widely applied. There is a large number of heat energy stored in hot dry rock. But the hot dry rock is usually located in deep-seated rocks of the earth. So it is rather difficult to utilize such deep resources directly. By means of working medium, heat energy could be delivered to ground and used properly. Usually, the heat exchange between medium and hot dry rock is achieved while the working medium flows through the rock crannies. The characteristic and structure of crannies in hot dry rock play a major role in heat transfer. It is very necessary to study characteristics of three-dimensional crannies and heat transfer effect of hot dry rack in order to reasonable development geothermal energy. The natural crannies in hot dry rock are quite narrow which cannot meet the needs of heat transport. The crannies used to heat exchange are usually produced by artificial explosion to obtain enough porosity. According to the distribution types of crannies after artificial explosion, The three-dimensional model of crannies is established, which is related to the identical porosity and variable porosities in different radius direction. In this paper, the hole with ideal shape is used to simulate crannies. The relationship among pressure, flux, velocity of working medium flowing through crannies and porosity are discussed based on fluid mechanics and heat transfer theory. The present study would have guiding significance in development and utilization of geothermal power.