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Factors defining spontaneous heating and ignition of Hay
Author(s) -
Currie J. A.,
Festenstein G. N.
Publication year - 1971
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740220505
Subject(s) - hay , latent heat , heat transfer , ignition system , relative humidity , humidity , chemistry , thermodynamics , environmental science , zoology , physics , biology
The ways in which heat balance, water balance and aeration interact in the self‐healing of hay beyond 70°c were examined in the laboratory. A temperature‐controlled environment is essential for the temperature of small hay samples to exceed 70°c; the rate at which airflows through the apparatus must be slower than that required for self‐heating below 70°c, in order to restrict loss of latent heat caused by increased water vapour transfer; otherwise, air at the same relative humidity as the hay must be used. Some water is essential for hay to self‐heat beyond 70°c, but self‐ignition occurs only when most of the water has been ha at or near 100°c. Theoretical considerations show that the latent heat transfer exceeds the thermal conductivity of hay above 20°c, increases by one order of magnitude by 65°c, two by 95°c and infinitely by 100°c.