Equivalence of Models of Freeze-Drying

Milena Veneva, William Lee

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Freeze-drying is a preservation process, consisting of two main stages: during the primary drying water is removed by sublimation; during the secondary drying chemically bound water is removed by desorption. Two different models of secondary drying are built. The first one consists of coupled heat and mass balances equations, the second one uses a modified Richards equation. Using scale transformations derived from the PDEs and the BCs, the first model is nondimensionalized. The model is further simplified by asymptotic reduction. It is proven that the reduced model is equivalent to the model that uses the modified Richards equation if the partial pressure of air is negligible compared to that of water vapor in the vials and in the chamber of the freeze-drier. This result shows that there is an opportunity for technology transfer, since solvers developed for modelling groundwater flows using Richards equations can also be used to model the economically important problem of freeze-drying.

Original languageEnglish
Title of host publicationAdvanced Computing in Industrial Mathematics
Subtitle of host publicationRevised Selected Papers of the 10th Annual Meeting of the Bulgarian Section of SIAM December 21-22, 2015, Sofia, Bulgaria
EditorsKrassimir Georgiev, Michail Todorov, Ivan Georgiev
PublisherSpringer International Publishing AG
Number of pages8
ISBN (Electronic)9783319495446, 9783319841854
ISBN (Print)9783319495439
Publication statusPublished - 13 Feb 2017
Externally publishedYes
Event10th Annual Meeting of the Bulgarian Section of SIAM - Sofia, Bulgaria
Duration: 21 Dec 201522 Dec 2015
Conference number: 10
http://www.math.bas.bg/IMIdocs/BGSIAM/bgsiam15_announcement.htm (Link to Conference Website)

Publication series

NameStudies in Computational Intelligence
ISSN (Print)1860-949X
ISSN (Electronic)1860-9503


Conference10th Annual Meeting of the Bulgarian Section of SIAM
Abbreviated titleBGSIAM 2015
Internet address


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