Известия Томского политехнического университета: Инжиниринг георесурсов (May 2019)
Prediction of temperature fields of building envelopes and ground for calculating the heat insulation of engineering lines in the climatic conditions of Yakutsk
Abstract
The relevance of the research is caused by the necessity to maintain the effective heat insulation of engineering lines at their underground laying in a zone of permafrost soils. The aim of the research is to predict temperature fields in building envelopes using the developed program complex, and in ground under a building and near it in the climatic conditions of Yakutsk; work out recommendations for effective warming of the engineering networks laid underground. Methods. The authors propose physical-mathematical model of the thermal state of underground taking into account the air exchange and design features of construction in permafrost conditions Numerical solution of the problem using the developed software package is made. Results. The authors developed the computational scheme of predicting temperature fields in building envelopes, in the ground under a building and near it in climatic conditions of Yakutsk. Numerical simulation of temperature fields' change of the basic building envelopes and the soil during a year was carried out. The comparative analysis of the obtained results with the empirical ones shown their satisfactory coordination. The authors selected the effective thickness of a warming layer of engineering lines at their underground laying in a zone of permafrost. Two-dimensional non-stationary symmetric problem of heat conductivity in semi-limited mass with a set of boundary conditions was considered. The authors proposed physical-mathematical model of heat exchange in a technical underground of a building taking into account the influence of air exchange and snow cover outside of a building and carried out a series of field experiments in Yakutsk to define the types of soil in a zone of construction. The results of numerical simulation showed that the warmth coming through the ceiling over technical underground and through the walls, does not actually influence the temperature of soils both under the building, and at distance from it. According to the carried out researches, temperatures in soil mass outside the construction zone are equal to their natural values. Comparison of results of the numerical solution with the solution obtained from other computer programs (for example, Temper-3D) showed their satisfactory coordination. Nevertheless, the program Temper-3D does not consider air exchange in a technical underground, which plays an essential role in formation of temperature fields in building envelopes and soil.
