Fire dynamics simulator- technical reference guide

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Fire Dynamics Simulator (Version 5): User's Guide

Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. Preface The use of fire models currently extends beyond the fire research laboratories and into the engineering, fire service and legal communities. Surveys [1, 2] of available fire models show a significant increase in number over the last decade. Sufficient evaluation of any model is necessary to ensure that users can judge the adequacy of its technical basis, appropriateness of its use, and confidence level of its predictions. This document provides the theoretical basis for the Fire Dynamics Simulator (FDS) and a summary of the work performed to evaluate the model. This guide is based in part on the " Standard Guide for Evaluating the Predictive Capability of De-terministic Fire Models, " ASTM E 1355 [3]. ASTM E 1355 defines model evaluation as " the process of quantifying the accuracy of chosen results from a model when applied for a specific use. " The model evaluation process consists of two main components: verification and validation. Verification is a process to check the correctness of the solution of the governing equations. Verification does not imply that the governing equations are appropriate; only that the equations are being solved correctly. Validation is a process to determine the appropriateness of the governing equations as a mathematical model of the physical phenomena of interest. Typically, validation involves comparing model results with experimental measurement. Differences that cannot be explained in terms of numerical errors in the model or uncertainty in the measurements are attributed to the assumptions and simplifications of the physical model. Evaluation is critical to establishing both the acceptable uses and limitations of a model. Throughout its development, FDS has undergone various forms of evaluation, both at NIST and beyond. This guide provides a survey of work conducted to date to evaluate FDS. Roughly half of the referenced studies were aimed primarily at model evaluation, the other half describe limited work to validate FDS for a specific use. The latter group were performed mostly by practicing engineers who did not have the time or resources to comprehensively evaluate the model. Collectively, the body …

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Fire dynamics simulator (Version 3) - Technical reference guide

The finite-volume method has been shown to effectively predict radiant exchange in geometrically simple enclosures where the medium is gray, absorbing, emitting, and scattering. Cartesian and circular cylindrical meshes have always been used. The present article shows that the method applies equally well to geometrically complex enclosures where nonorthogonal, boundary-fitted meshes are used. This development permits radiant heat transfer to be computed on the same mesh employed to solve the equations of fluid motion.

Computation of radiant heat transfer on a nonorthogonal mesh using the finite-volume method

This chapter presents a finite-volume (FV) method for computing radiation heat transfer processes The main ingredients of the calculation procedure were presented by Chai et al [1] The resulting method has been tested, refined and extended to account for various geometrical and physical complexities

Finite volume method for radiation heat transfer

A new finite-volume method is proposed to predict radiant heat transfer in enclosures with participating media. The method can conceptually be applied with the same nonorthogonal computational grids used to compute fluid flow and convective heat transfer. A fairly general version of the method is derived, and details are illustrated by applying it to several simple benchmark problems. Test results indicate that good accuracy is obtained on coarse computational grids, and that solution errors diminish rapidly as the grid is refined.

E. H. Chui

Papers

A Finite-Volume Method for Predicting a Radiant Heat Transfer in Enclosures With Participating Media