Premium
A Finite Element Calculation for Determining Thermal Conductivity
Author(s) -
Riha Susan J.,
McInnes K. J.,
Childs S. W.,
Campbell G. S.
Publication year - 1980
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1980.03615995004400060039x
Subject(s) - thermal conductivity , loam , materials science , conductivity , hydraulic conductivity , porosity , silt , finite element method , analytical chemistry (journal) , thermodynamics , mineralogy , composite material , chemistry , soil science , soil water , geology , chromatography , physics , paleontology
A new simple method for in situ measurement of thermal conductivity of porous materials was developed. A heated or cooled Al or glass probe was placed in soil, and its temperature was monitored over time. Thermal conductivity was determined using a finite element method to solve the radial heat flow equation for the temperature of the heated or cooled probe. The probe temperature, as a function of time, was modeled, and model thermal conductivity was adjusted until predicted probe temperatures agreed with measured values. Conductivities for sand, silt loam, and forest litter were measured over a range of water contents. Values obtained using a glass probe were not significantly different from those obtained using an Al probe. Conductivities were in good agreement with those obtained using a water bath method or computed from the deVries equation. There were significant differences between values obtained with heated and cooled probes in sand at intermediate water content.