Title: Determination of heat transfer coefficients for complex spray cooling arrangements

Authors: Sebastian Herbst; Kim-Florian Steinke; Hans Jürgen Maier; Andrzej Milenin; Florian Nürnberger

Addresses: Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, Garbsen, 30823, Germany ' Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, Garbsen, 30823, Germany ' Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, Garbsen, 30823, Germany; Zentrum für Festkörperchemie und Neue Materialien, Leibniz Universität Hannover, Callinstr. 9, Hannover, 30167, Germany ' AGH University of Science and Technology Kraków, Mickiewicza 30, Kraków, 30-059, Poland ' Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, Garbsen, 30823, Germany; Zentrum für Festkörperchemie und Neue Materialien, Leibniz Universität Hannover, Callinstr. 9, Hannover, 30167, Germany

Abstract: Numerical simulation of quenching by air-water spray cooling requires an accurate knowledge of the spray heat transfer coefficients (HTCs). In this work, a novel method of heat transfer determination is presented that takes lacking aspects of prior determination methods into account. The temperature trends during cooling of a thin-walled tube are used in an optimisation calculation based on a numerical model of the setup to determine the HTCs. It is shown that higher inlet pressures lead to higher heat transfers and that the heat transfer between two spray nozzles increases with decreasing nozzle to nozzle distance. However, for some cases, adjacent sprays can lead to decreasing HTCs. The amount of nozzles in circumferential direction had an overproportioned effect on the heat transfer in the film boiling regime. Verifications generally show a good agreement of measured with computed temperature trends based on the calculated HTCs.

Keywords: HTC; heat transfer coefficient; air-water spray cooling; optimisation; numerical simulation; spray overlapping; nozzle count; verification; heat flow; quenching; heat treatment; thin-walled tubes; modelling; inlet pressure; film boiling.

DOI: 10.1504/IJMMP.2016.079149

International Journal of Microstructure and Materials Properties, 2016 Vol.11 No.3/4, pp.229 - 246

Received: 03 Dec 2015
Accepted: 03 Feb 2016
Published online: 14 Sep 2016 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article