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Analyzing and Exploiting Numerical Characteristics of Zone Fire Models.


pdf icon Analyzing and Exploiting Numerical Characteristics of Zone Fire Models. (612 K)
Forney, G. P.; Moss, W. F.

NISTIR 4763; 44 p. March 1992.

Fire Science and Technology, Vol. 14, No. 1/2, 49-60, 1994.

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
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Order number: PB92-172790

Keywords:

zone models; fire models; computer models; numerical analysis

Abstract:

In order to design robust and stable zone fire modeling algorithms, the numerical properties of computer arithmetic and modeling differential equations must be understood. This report examines some of these properties and provides tools for their analysis. Many sets of different equations for zone fire modeling can be derived using the conservation of mass and energy. A comparison between various possible formulations is made in terms of numerical properties. One property that many formulations possess is the presence of multiple time scales. Pressures equilibrate much faster than other quantities such as density and temperature. Numerically, this property is known as stiffness. Stiffness, in the context of fire modeling, and numerical methods for handling it are discussed.