Premium
Heat pipe phenomenon in soil under reduced air pressure
Author(s) -
Sakaguchi I.,
Momose T.,
Mochizuki H.,
Kasubuchi T.
Publication year - 2009
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2008.01095.x
Subject(s) - latent heat , water content , heat transfer , homogeneous , temperature gradient , heat flux , chemistry , soil water , thermodynamics , soil science , environmental science , geology , geotechnical engineering , meteorology , physics
Summary We measured the heat flux, temperature distribution and water content of an unsaturated Ando soil under a constant temperature gradient and reduced air pressure to investigate the mechanism of latent heat transfer in the soil and its relationship to the distribution and circulation of soil water. As the air pressure decreased, the heat flux increased for the soil samples with an initial volumetric water content ( θ ini ) greater than 0.30 m 3 m −3 , but did not change for θ ini less than 0.20. While the temperature gradient of the sample did not change for θ ini greater than 0.30 m 3 m −3 , it did increase on the hotter side of the sample and decreased on the colder side for θ ini less than 0.20. The water content did not change, and a homogeneous distribution of water content was observed for θ ini greater than 0.30 m 3 m −3 . For θ ini less than 0.20, the water content decreased on the hotter side and increased on the colder side, forming a large water content gradient. The large transfer of latent heat was caused by the circulation of water vapour and liquid water, which resulted in the homogeneous water distribution. We concluded that the soil functions as a heat pipe through a series of micro‐heat pipes centred on the soil pores. Our experimental results will help to explain the transfer mechanism of latent heat in soil as a heat pipe phenomenon.