Experimental and numerical study of heat transfer in a large-scale vertical falling film pilot unit
Journal article, 2018

Heat transfer in a large-scale vertical falling film pilot unit is investigated experimentally and numerically. We study a broad range of operating conditions with Kapitza and Reynolds numbers ranging from Ka = 167-7010 and Re 18-1854, respectively. We compare local heat transfer measurements, conducted over a vertical length of 4 meters, with those obtained by directly solving the full Navier-Stokes equations in two dimensions and using the volume of fluid (VOF) numerical framework. We examine the development region along with the one in which we assume statistically steady conditions. In both our experiments and simulations we see significant differences between the two regions in terms of the magnitude of the heat transfer coefficient. We show how this is a result of the temperature gradient within the liquid film, along with the thickness of the liquid film. The degree of bulk mixing, introduced by the waves, has a profound influence on the thermal boundary layer and depends strongly on the fluid properties and the operating conditions.

Large scale unit

VOF

Falling Film

Heat Transfer

Author

Anders Åkesjö

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Reaction Engineering

Mathias Gourdon

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Lennart Vamling

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Reaction Engineering

Innings Fredrik

Tetra Pak

Srdjan Sasic

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

International Journal of Heat and Mass Transfer

0017-9310 (ISSN)

Vol. 125C 53-65

Energy efficient falling-film evaporation through modified heating surfaces

Swedish Energy Agency, 2015-07-01 -- 2018-12-31.

Subject Categories

Energy Engineering

Other Chemical Engineering

Fluid Mechanics and Acoustics

Areas of Advance

Energy

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1016/j.ijheatmasstransfer.2018.04.052

More information

Latest update

8/6/2018 5