Optimal Control Of A Freeze Dryer-II. Dynamic Analysis

Abstract

The unsteady state model and Lagrangian equations of the freeze-drying process presented in Part I[4], have been solved for non-fat reconstituted milk and turkey, using the control strategies presented in [4]; the results were then used to evaluate the coefficients representing the necessary conditions of optimality. The results for non-fat reconstituted milk confirm the results of the quasi-steady state analysis [4], except for a time segment very close to t = 0. Simulations with turkey breast showed similar results at low pressures, but it was found that at higher pressures the assumed control policies which were based on a quasi-steady state analysis[4], were not optimal. The non-steady state results indicate that for turkey, intermediate rather than maximum, pressure control policies were optimal for cases (a) and (b) in[4]. However, in practice these optimal pressure policies might produce only minor improvements in drying time when compared with a near optimal policy. It was also found that changes in the interface constraint affected drying times only marginally, but that large heaters operating under optimal control had a pronounced effect on the drying time. © 1982.

Department(s)

Chemical and Biochemical Engineering

International Standard Serial Number (ISSN)

0009-2509

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2023 Elsevier, All rights reserved.

Publication Date

01 Jan 1982

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