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Comparison of Algorithms to Calculate Plume Centerline Temperature and Ceiling Jet Temperature With Experiments.


pdf icon Comparison of Algorithms to Calculate Plume Centerline Temperature and Ceiling Jet Temperature With Experiments. (261 K)
Davis, W. D.

NISTIR 6448; 35 p. January 2000.

Journal of Fire Protection Engineering, Vol. 12, No. 1, 9-29, 2002.

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
Telephone: 1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: PB2000-101595

Keywords:

ceiling height; predictive models; ceiling jets; experiments; fire models; fire plumes; zone models

Abstract:

The predictive capability of two algorithms designed to calculate plume centerline temperature (Evans) and maximum ceiling jet temperature (Davis et. al.) in the presence of a hot upper layer are compared with measurements from a series of experiments. In addition, comparisons are made using the ceiling jet algorithm in CFAST (version 3.1), the unconfined plume algorithm of Heskestad, and the unconfined ceiling jet algorithm of Alpert. The experiments included ceiling heights of 0.58 m to 22 m and heat release rates (HRR) of 0.62 kW to 33 MW. It was shown that the unconfined ceiling algorithms underpredicted the temperatures while the ceiling jet algorithm in CFAST overpredicted the temperature in the presence of a hot layer. With the combined uncertainty of the measurement and the calculation roughly equal to +20%, the algorithms of both Evans and Davis et. al. consistently provided predictions either close to or within this uncertainty interval for all fire sizes and ceiling heights.