ABSTRACT
In this article, a numerical model for simulation of the heat and mass transfer phenomena in unsaturated soil is presented. The system is provided to evaluate its behavior as a thermal storage system. The model includes a single pipe that is buried under unsaturated media which is connected to a source with the constant heat rate of 20 W/m3 in sandy soils during a specific time. All the numerical results show good agreement with previous results, thus excellent correlation was achieved. Additionally, sensitivity analysis is done to clear up the role of the thermal and isothermal properties respect to volumetric water content and temperature and to assess the effects of related parameters on heat transfer in the media. The results show that as getting far away from the source, in addition to reduce the collected energy, the intensity of increasing the temperature and decreasing the moisture diminished will be more. Generally over time, the cumulative stored energy for each point will tend to a constant quantity.
Nomenclature
cP | = | specific heat capacity (J/kg K) |
L | = | latent heat (J/kg) |
ks | = | thermal conductivity (W/mK) |
D | = | molecular diffusivity ( |
g | = | acceleration of gravity (m/s2) |
R | = | universal gas constant (J/mol K) |
T | = | absolute temperature (K) |
RH | = | relative humidity (%) |
Q | = | received energy (W/m3) |
K | = | unsaturated hydraulic conductivity (m/s) |
ρ | = | density (kg/m3) |
θ | = | volumetric water content (kg/kg) |
ψ | = | matric suction head (m) |
α | = | tortuosity factor for soil |
β | = | cross-sectional area of the soil |
λ | = | coefficient of thermal conductivity (W/mK) |
Subscripts | ||
l | = | liquid |
v | = | vapor |
Tl | = | thermal capacity |
θl | = | isothermal capacity |
Nomenclature
cP | = | specific heat capacity (J/kg K) |
L | = | latent heat (J/kg) |
ks | = | thermal conductivity (W/mK) |
D | = | molecular diffusivity ( |
g | = | acceleration of gravity (m/s2) |
R | = | universal gas constant (J/mol K) |
T | = | absolute temperature (K) |
RH | = | relative humidity (%) |
Q | = | received energy (W/m3) |
K | = | unsaturated hydraulic conductivity (m/s) |
ρ | = | density (kg/m3) |
θ | = | volumetric water content (kg/kg) |
ψ | = | matric suction head (m) |
α | = | tortuosity factor for soil |
β | = | cross-sectional area of the soil |
λ | = | coefficient of thermal conductivity (W/mK) |
Subscripts | ||
l | = | liquid |
v | = | vapor |
Tl | = | thermal capacity |
θl | = | isothermal capacity |