ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Theory is outlined relative to the effect of pressure on permeabilities and thermal conductivities of gases in porous solids in the slip flow and free-molecule flow regions, and experimental results are reported for several freeze-dried food materials. Mean pore diameters for the porous materials calculated from permeability data were about 100 μ and were in agreement with microscopic observations. Thermal conductivities followed the predicted behavior of a constant value at high pressures, with a gradual decrease to another constant value at very low pressures. The results show that the usual operating pressure range of freeze-dryers (0.1 to 1.0 mm. Hg) corresponds to the transition region between slip flow and free-molecule flow.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690080308
