Title: Heat transfer mechanisms analysed by high speed video recording of metal quenching in ionic liquids and water

Authors: Martin Beck; Christin Neise; Mathias Ahrenberg; Christoph Schick; Udo Kragl; Olaf Kessler

Addresses: Materials Science, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18059, Germany ' Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, Rostock, 18059, Germany ' Institute of Physics, University of Rostock, Albert-Einstein-Straße 23-24, Rostock, 18051, Germany ' Institute of Physics, University of Rostock, Albert-Einstein-Straße 23-24, Rostock, 18051, Germany ' Institute of Chemistry, University of Rostock, Albert-Einstein-Straße 3a, Rostock, 18059, Germany ' Materials Science, University of Rostock, Albert-Einstein-Straße 2, Rostock, 18059, Germany

Abstract: To understand and control the heat transfer mechanisms of ionic liquids (ILs) as a new group of potential liquid quenching media, aluminium and steel cylinders are quenched in ionic liquids with varying water contents as well as pure water with different bath temperatures. Due to the very fast changes between the different heat transfer mechanisms, the quenching processes are recorded with a high speed video camera with up to 4000 frames per second. The videos are correlated with the temperature-time profiles of the cylinders to identify and investigate the different heat transfer mechanisms. As a result, no Leidenfrost-effect occurred in pure ionic liquids and only very short-film boiling sequences of a few 0.1 s could be identified in ionic liquid-water mixtures. Advantages, optimisations and limits of high speed video recording of quenching processes are discussed.

Keywords: ionic liquids; heat transfer; Leidenfrost effect; high speed video; metal quenching; water; aluminium cylinders; steel cylinders; bath temperature.

DOI: 10.1504/IJMMP.2016.080698

International Journal of Microstructure and Materials Properties, 2016 Vol.11 No.5, pp.359 - 372

Received: 10 Dec 2015
Accepted: 11 May 2016
Published online: 04 Dec 2016 *

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