کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
157232 456966 2009 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Cavern formation in pulp suspensions using side-entering axial-flow impellers
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Cavern formation in pulp suspensions using side-entering axial-flow impellers
چکیده انگلیسی

Pulp fibre suspensions display non-Newtonian rheology, including a yield stress. In mixing operations, this creates regions of active motion around the impellers with the cavern size affecting the quality of mixing attained. Due to the opacity of the suspensions, two non-invasive techniques were evaluated for determining cavern dimensions: electrical resistance tomography (ERT) and ultrasonic Doppler velocimetry (UDV), with ERT chosen for most tests due to the speed of data acquisition. Cavern volume as a function of impeller speed is reported for a range of mixing conditions (hardwood and softwood pulp, suspension mass concentrations from one to five percent, two impeller offsets from the wall, and three suspension height-to-chest diameter ratios). A scaled version of a commercial axial flow impeller was used in a standard side-entering configuration. Measured cavern diameters were compared against model predictions available in the literature. The discrepancy between experimental data and model predictions were significant and were attributed to interaction between the developing cavern and the vessel walls. An alternative model was developed for predicting cavern volume taking this interaction into account.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Science - Volume 64, Issue 3, February 2009, Pages 509–519
نویسندگان
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