An experimental study of dynamic jet behaviour in a scaled cold flow spray dryer model using PIV

Journal article (2014)

Authors

Sandip Pawar Eindhoven University of Technology
Ruud H.M. Abrahams Eindhoven University of Technology
Niels G. Deen Eindhoven University of Technology
J.T. Padding Eindhoven University of Technology
Gert Jan van der Gulik Tetra Pak CPS
Alfred Jongsma Tetra Pak CPS
Fredrik Innings Tetra Pak CPS
J. A.M. Hans Kuipers Eindhoven University of Technology
Affiliation
External organisation
Particle image velocimetry Proper orthogonal decomposition Spray dryer Turbulent jet flow
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Published Date

2014

Language

English

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Abstract

Research on the dynamic flow behaviour in spray dryers has a long history. Interest in describing these flows originates from problems like roof and wall fouling. The aim of the present study is to experimentally investigate the dynamic jet behaviour and turbulent flow in a scaled-down cold flow model of a spray dryer in order to better understand and optimize spray drying units. Dynamic jet behaviour and turbulent flow features (i.e., RMS velocities) were studied by particle image velocimetry (PIV) using water as the continuous phase. To obtain more insight in the jet dynamics, we analyzed the turning point, the width and shape, and the velocity profiles of the turbulent jet at different heights and the turbulence characteristics. We found that at higher Reynolds numbers, the jet penetrates further along the downward direction with a time-averaged profile which is symmetric at the centre. In addition, we investigated the effect of the expansion ratio via proper orthogonal decomposition (POD). Outcomes of different characteristics of the dynamic jet, like steady, transient, regular, and complex precession, can be collapsed by proper scaling. These results can be used for validation of computational fluid dynamics simulations and facilitate the design (identification of jet operation boundaries) of new spray dryer configurations.