Abstract

The goal of this study was to determine the conductive and steam-diffusive heat transfer constituents in the soil. Based on the solution of differential equation system of heat and mass transfer, the method to determine the conductive and steam-diffusive heat transfer constituents in wet soils was developed. To measure the thermophysical properties in laboratory setting, a pulse method of a two-dimensional heat source was used. The method takes into account the patterns of temperature field equalization in an unbounded medium after the heat source termination. A feature of this process is the occurrence of peak temperature at the investigated point of the medium at a given instant. In this experiment, the temperature was controlled not only at the investigated point of the medium, but also at the soil-heater interface. The proposed method was used to study the thermophysical indices of the chernozems of the Altai Region’s Priobye area (the Ob River area). The chernozem under study is of light-loamy particle-size composition; the illuvial horizon В is enriched by a sand fraction. It has been found that the soil conductive thermal diffusivity is reduced with increasing moisture content. The steam-diffusive thermal diffusivity has the extremum at the moisture close to the discontinuous capillary moisture. In humus horizons it plays a smaller role than in the mineral horizons. The thermal diffusivity determined by the steam molecule motion in the pore space of the soil exceeds the conductive thermal diffusivity two or three times. At the same time thermal steam diffusivity is more than ten time lower than the conductive constituent. Eventually, the stem molecules though dramatically accelerating the processes of heat transfer in the soil profile conduct a small amount of heat and make a weak contribution to soil thermal accumulation.

Keywords: Soil, thermal capacity, thermal conductivity, thermal diffusivity, thermo-transference in soils, conductive and steam-diffuse constituents

References

Anikonov, Yu.Ye., Bubnov, B.A., 1981. Existence and uniqueness of solution of inverse problem of parabolic equation. Doklady Akademii Nauk SSSR (The Proceedings of the USSR Academy of Sciences) 289 (4): 777-779 [in Russian].

Arkhangelskaya, T.A., 2014. Diversity of thermal conditions within the paleocryogenic soil complexes of the East European Plain: The discussion of key factors and mathematical modeling. Geoderma 213: 608-616.

Bolotov, A.G., Makarychev, S.V., 2015. Hydrophysical properties of the soils of the south-east of West Siberia. Altai State Agricultural University (ASAU) Publishing Division. Barnaul, Russia. 129 pp. [in Russian].

Chudnovskiy, A.F., 1976. Soil thermal physics. Nauka. Moscow, Russia. 352 pp. [in Russian].

Globus, A.M., 1983. Physics of non-isothermal in-soil moisture exchange. Leningrad: pp. 64-69 [in Russian].

Globus, A.M., 1987. Soil-hydrophysical support of agro-ecological mathematical models. Leningrad. 427 pp. [in Russian].

Gülser, C., Ekberli, I., 2004. A Comparison of estimated and measured diurnal soil temperature through a clay soil depth. Journal of Applied Science 4(3): 418-423.

Kaye, G.W.C., Laby, T.H., 1995. Tables of physical and chemical constants. Longman. 16 th edition, UK. 611 pp.

Lavrentyev, M.M., 1986. Inner problems for differential equations. Partial differential equations. Novosibirsk, Nauka, Russia. pp. 126-129 [in Russian].

Lunin, A.I., 1972. Pulse method of definition thermophysical properties of wet construction materials. Thesis Abstract. Cand. Sci. Moscow. Russia. MISI. 18 pp. [in Russian].

Makarychev, S.V., Mazirov, M.A., 1996. Soil thermal physics: methodology and properties. Vol. 2. VRIA. Suzdal, Russia. 231 pp.  [in Russian].

Mikayilov, F.D., Shein, E.V., 2010. Theoretical principles of experimental methods for determining the thermal diffusivity of soils.  Eurasian Soil Science 43(5): 556–564.

Nerpin, S.V., Chudnovskiy, A.F., 1970. Physics of the soil (Translated from Russian, 1967) Isreal program for scientific translations, Keter Press, Jerusalem, Israel. pp.194–233.

Panfilov V.P., Makarychev S.V. 1981. Thermophysical properties and regimes of the chernozem soils of the Priobye (Ob River area). Novosibirsk. Nauka. Russia. pp. 18-24 [in Russian].

Philip, J.R., De Vries, D.A., 1957. Simultaneous heat and moisture transfer in porous media. Eos, Transactions American Geophysical Union 38 (2): 222-232.

Tikhonov, A.N., Arsenin, V.Ya., 1979. Methods of solution of incorrect problem. Moskow. Nauka. Russia. 288 pp. [in Russian].