Heat transfer for falling film evaporation of black liquor up to very high Prandtl numbers
Journal article, 2013

In this study, heat transfer measurements for falling film evaporation were performed up to very high Prandtl numbers, from 10 to 2800. Black liquor, a residual stream from the pulping process, was used as an example of a fluid that can have very high Prandtl numbers. To overcome the problem with fouling, which can be severe for black liquor due to crystal formation at higher concentrations, a new measurement method has been successfully developed which enables reliable measurements. Viscosity was clearly the most important parameter for the heat transfer coefficient, while the specific mass flow rate had a weak and positive dependence. The results were compared with existing heat transfer correlations, but none of them were able to capture the heat transfer behavior of black liquor throughout the whole range of Prandtl numbers. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

Falling film


Heat transfer


Black liquor


High Prandtl numbers




Erik Karlsson

Industrial Energy Systems and Technologies

Mathias Gourdon

Industrial Energy Systems and Technologies

Lars Olausson

Metso power AB

Lennart Vamling

Industrial Energy Systems and Technologies

International Journal of Heat and Mass Transfer

0017-9310 (ISSN)

Vol. 65 907-918

Subject Categories

Energy Engineering

Chemical Process Engineering

Areas of Advance




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