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The length of a transfer unit (LTU) for polymer devolatilization processes in screw extruders
Author(s) -
Collins G. P.,
Denson C. D.,
Astarita G.
Publication year - 1983
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760230606
Subject(s) - materials science , plastics extrusion , process (computing) , unit (ring theory) , polymer , relation (database) , transfer (computing) , mechanics , computer science , composite material , mathematics , physics , mathematics education , parallel computing , operating system , database
In this paper we introduce the concept of the length of a transfer unit (LTU) for polymer devolatilization and show that the LTU is an appropriate measure of the effectiveness of the process unit in which the devolatilization operation is conducted. The utility of the concept is demonstrated for the case when the process unit is a twin screw extruder for which values of the LTU were determined from experimentally measured values of devolatilization rates. Values of the LTU were found to depend solely on the fluid mechanics in the extruder as expected and were in good agreement with the predictions of a theoretical expression developed for the system that was studied. Finally, we discuss the implications of the LTU concept in relation to the engineering design and analysis of polymer devolatilization processes.