Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

M. Raudensky
Brno University of Technology, Czech Republic

J. Horsky
Brno University of Technology, Czech Republic

P. Kotrbacek
Brno University of Technology, Czech Republic

This paper presents the results from a program of extensive laboratory experiments. A rotating cylinder is cooled by a set of spray nozzles. The study concerns an initial cylinder temperature at 350 °C and cooling is done using water at 20 °C. Circumferential velocity of the roll varies within the range 0.1 to 10 m/s.
The following parameters of spray are studied: coolant pressure, flow-rate, and spray height and impact angle. The achievable result is the heat transfer coefficient distribution on the roll surface. This paper deals in particular with the questions of both the influence of circumferential velocity and surface temperature of the rotating cylinder. The results of experimental study of mutual influence of neighbouring sprays are also discussed.
The research was motivated by its useful application in the spray cooling of rolls in the rolling process, where characteristics of the cooling system can strongly influence the quality of production as well as the working life of rolls, mentioned by Downey (1997) and by Saha et al (2005). Cooling medium transport to the roll surface is achieved by a series of nozzles positioned in rows thereby forming the shape of coolant jet in the impact area. Cooling intensity can be controlled by coolant pressure and by the number of manifolds in operation. When the roll surface is overflowed, fresh coolant supplied by the bottom rows of nozzles cannot penetrate the coolant layer caused by the upper rows of nozzles, and the heat transfer mechanism becomes saturated.

JET-25 pages DOI: 10.1615/IHTC13.p16.240 Download article

Article price - $35.00

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