Refined Method of Calculation of Freezing of External Fences and Moistened Materials

The relevance of the study is related to the need to ensure the safety of human life and building structures when the building cools down during the cold season in the event of an emergency shutdown of heat supply systems. The subject of the study is the time dependences for the position of the moisture freezing front and the transverse temperature profile in external fences in conditions of a sharp cold snap. The purpose of the study is to assess the error of such dependencies and obtain more accurate versions of them, more fully reflecting the physical essence of the processes occurring during freezing. The objective of the study is to compare the behavior of the temperature inside the fence within the frozen or thawed zone and the freezing front according to different methods and to search for correction coefficients that ensure the best agreement of the results. Materials and research methods used. A combination of approximate analytical and numerical finite-difference methods for solving differential equations of unsteady thermal conductivity in an array of room fences is used to solve the one-dimensional Stefan problem using approximation of the temperature profile within the frozen or thawed zone in the form of a quadratic polynomial. The sequence of obtaining a refined analytical expression for the spatial coordinate of the freezing front under boundary conditions of the first kind is shown and a calculated transverse temperature profile is presented depending on the coordinate for a characteristic example of a moistened outer wall material. The obtained results are compared with the available approximate solution and the results of numerical calculations according to the computer program developed earlier by the author, their differences are identified and justified and an accuracy assessment is carried out.

O.D. SAMARIN, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.)

National Research Moscow State University of Civil Engineering (26, Yaroslavskoe Highway, Moscow, 129337, Russian Federation)

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