Simulation of heat stabilizer with a distributed refrigerant supply to the outer surface

Abstract

To prevent the breaking of buildings in the cryolithozone due to thawing of permafrost soil due to thermal load from these objects, it is necessary to use heat stabilizers. Two-phase passive thermosyphons are widely used among them. To increase the efficiency of such device, a design of a heat stabilizer with a distributed refrigerant supply to the outer surface is proposed. Determining the optimal operating parameters of such device is impossible without a stage of modeling heat and mass transfer. This determines the purpose of the study — the calculation of the temperature distribution in the ground with such heat stabilizer. A calculation is carried out using physico-mathematical model of it with three related tasks: 1) description of the movement of liquid refrigerant through the inner tube of the thermosyphon; 2) calculation of the upward flow of refrigerant in the gap between the outer tube and the segments of the flow separator; 3) calculation of conductive heat transfer in the heat stabilizer-soil system. The modeling is based on the approaches of non-isothermal multiphase mechanics and thermophysics. The temperature profile was calculated in the gap between the flow-separating device consisting of four segments and the heat stabilizer pipe, as well as in the soil at 1 m from the surface of the thermosyphon. The proposed model makes it possible to determine the radial temperature distribution consistent with practical data with an accuracy of 90%. It was found that the use of such separating device can increase the efficiency of reducing soil temperature by 20%.