ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
INFLUENCE OF A TOTAL PRESSURE GRADIENT IN GASEOUS PHASE ON DRYING WITH PARTICULAR REFERENCE TO WOOD
Abstract
New drying processes, which accelerate considerably
the drying rate, require to take in account
a filtration motion inside the body which is induced
by a total pressure gradient in gaseous phase.
This paper, with particular reference to wood,
studies the manner in which a numerical model can
simulate this problem by introducing a third equation
in the classical two equations system in the
case of a convective drying.
For an air temperature θ∞ = 100°C, the taking in account of pressure gradient accelerates the drying. We show that the time necessary to dry a wood from an initial moisture ω = 80% to a final value ω = 10% is reduced of about 13%.
Simultaneously experimental results about vacuum contact drying are presented which point out the influence of the external pressure on the drying rate. The experimental apparatus provides also the temperature evolutions in space and in time during the drying. This permits to distinguish three stages of drying and to give informations on the moisture movement migration during vacuum contact drying of a wood sample.
For an air temperature θ∞ = 100°C, the taking in account of pressure gradient accelerates the drying. We show that the time necessary to dry a wood from an initial moisture ω = 80% to a final value ω = 10% is reduced of about 13%.
Simultaneously experimental results about vacuum contact drying are presented which point out the influence of the external pressure on the drying rate. The experimental apparatus provides also the temperature evolutions in space and in time during the drying. This permits to distinguish three stages of drying and to give informations on the moisture movement migration during vacuum contact drying of a wood sample.