fulltext.study @t Gmail

Friction factors, convective heat transfer coefficients and the Colburn analogy for industrial sugarcane juices

Paper ID Volume ID Publish Year Pages File Format Full-Text
3670 181 2012 8 PDF Available
Title
Friction factors, convective heat transfer coefficients and the Colburn analogy for industrial sugarcane juices
Abstract

Sugarcane (Saccharum sp.) is a relatively low-cost agricultural resource, produced mainly in tropical and subtropical regions of the planet. One of the most important applications of sugarcane juice is in the production of ethanol biofuel. A correct design of unit operations during the sugarcane juice processing requires an accurate characterization of the flow properties (friction factors, rheological behaviour, thermophysical properties and heat transfer coefficients) of this raw material. In this work, friction factors (f) and Nusselt number (Nu) were determined for sugarcane juice in different steps of its processing (untreated sugarcane juice, clarified sugarcane juice and mixed sugarcane juice). For both laminar and turbulent flows, the empirical models for f fitted well (r2 ≥ 0.9) with the experimental values obtained by pressure drop measurements. Also, Nu values calculated by applying the empirical correlation of Hausen (for laminar flow) and that of Sieder–Tate (for turbulent flow) presented good adjustment (r2 ≥ 0.9) to the experimentally determined values. Thus, the f and Nu values obtained for turbulent flow were taken to verify the Colburn analogy, which furnished results with small deviations (≤8.9%) from the expected ideal value. This finding indicates the suitability of such analogy in this case, allowing good estimations of heat transfer coefficients from frictions factors, or vice versa, for sugarcane juices in turbulent flow conditions.

► Friction factors and Nusselt numbers were determined for sugarcane juices sampled from an industrial processing line. ► These experimentally determined data showed a good correlation with those calculated by means of empirical correlations. ► The Colburn analogy was successfully applied to obtain heat transfer coefficients from friction factor values in turbulent flow. ► New data outlined in this work will be useful to improve the processing of sugarcane juice for ethanol fuel production.

Keywords
Biofuel; Colburn analogy; Ethanol; Friction factor; Heat transfer; Sugarcane
First Page Preview
Friction factors, convective heat transfer coefficients and the Colburn analogy for industrial sugarcane juices
Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 60, 15 January 2012, Pages 111–118
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering