Heat transfer coefficient effects on spray cooling

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Iron and Steel Engineer

OSTI ID:118858

Stewart, I; Massingham, J D ^[1]; Hagers, J ^[2]

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1. British Steel Technical, Moorgate (United Kingdom). Swinden Technology Center
2. Spraying Systems Co., Wheaton, IL (United States)

Spray cooling is an integral part of many manufacturing processes and is particularly relevant to high-temperature process. It may be used to simply allow the survival of a unit or to insure that a unit operates at an acceptable temperature. A more recent trend is to use spray cooling to control the final properties of the product. Particular problems are experienced when cooling from the high temperature, stable film boiling regime through Leidenfrost to nucleate boiling. In this case, the published relationships between spray impact density (liters/s/sq meter) and heat transfer coefficient (HTC) are of little use, becoming very inaccurate as cooling proceeds. Mathematical models of cooling are well developed and reliable but need accurate information on the heat removal conditions at the surface of the stock. A test apparatus using a stainless steel specimen cooled from 1,200 C to ambient has been used to investigate the HTC`s from various types of spray, both pressure atomized and air mist, by a transient method. The temperature history is supplied to a mathematical model which works in a reverse iterative manner but with a convergence function. This gives a relationship between HTC and stock temperature over the entire temperature range. Relationships between impact density and HTC are presented for various nozzles and suggestions for further work are made.

• OSTI ID: 118858
• Report Number(s): CONF-9509197--
• Journal Information: Iron and Steel Engineer, Journal Name: Iron and Steel Engineer Journal Issue: 7 Vol. 72; ISSN IRSEA5; ISSN 0021-1559
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COEFFICIENT OF PERFORMANCE
COOLING SYSTEMS
EFFICIENCY
HEAT TRANSFER
MATHEMATICAL MODELS
NOZZLES
SPRAY COOLING