Validation of the Isis-3D Computer Code for Simulating Large Pool Fires Under a Variety of Wind Conditions

2003 ◽  
Author(s):  
Miles Greiner ◽  
Ahti Sou-Anttila
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Temperature Response ◽  
Diffuse Radiation ◽  
Computer Code ◽  
Time Dependent ◽  
Fuel Vapor ◽  
View Factor ◽  
Pool Fires ◽  
Fuel Evaporation

The Isis-3D computational fluid dynamics/radiation heat transfer code was developed to simulate heat transfer from large fires. It models liquid fuel evaporation, fuel vapor and oxygen transport, chemical reaction and heat release, soot and intermediate species formation/destruction, diffuse radiation within the fire, and view factor radiation from the fire edge to nearby objects and the surroundings. Reaction rate and soot radiation parameters in Isis-3D have been selected based on experimental data. One-dimensional transient conduction modules calculate the response of simple objects engulfed in and near the flames. In this work, Isis-3D calculations were performed to simulate the conditions of three experiments that measured the temperature response of a 4.66-m-diameter culvert pipe located at the leeward edge of 18.9-m and 9.45-m diameter pool fires in crosswinds with average speeds of 2.0, 4.6 and 9.5 m/s. The measured wind conditions were used to formulate time-dependent velocity boundary conditions for a rectangular Isis-3D domain with 16,500 nodes. Isis-3D accurately calculated characteristics of the time-dependent temperature distributions in all three experiments. Accelerated simulations were also performed in which the pipe specific heat was reduced compared to the measured value by a factor of four. This artificially increased the speed at which the pipe temperature rose and allowed the simulated fire duration to be reduced by a factor of four. A 700 sec fire with moderately unsteady wind conditions was accurately simulated in 10 hours on a 2.4 GHz LINUX workstation with 0.5 GB of RAM.

Validation of the Isis-3D Computer Code for Simulating Large Pool Fires Under a Variety of Wind Conditions

2004 ◽  
Vol 126 (3) ◽  
pp. 360-368 ◽  
Author(s):  
Miles Greiner ◽  
Ahti Suo-Anttila
Keyword(s):  
Heat Transfer ◽  
Reaction Rate ◽  
Radiation Heat Transfer ◽  
Temperature Response ◽  
Computer Code ◽  
Computational Grids ◽  
Model Parameters ◽  
Pool Fires ◽  
Radiation Heat ◽  
Transportation Risk

The Isis-3D computational fluid dynamics/radiation heat transfer computer code was developed to simulate heat transfer from large fires to engulfed packages for transportation risk studies. These studies require accurate estimates of the total heat transfer to an object and the general characteristics of the object temperature distribution for a variety of fire environments. Since risk studies require multiple simulations, analysis tools must be rapid as well as accurate. In order to meet these needs Isis-3D employs fuel evaporation reaction rate and radiation heat transfer models that allow it to accurately model large-fire heat transfer even when relatively coarse computational grids are employed. Reaction rate and soot radiation model parameters in Isis-3D have been selected based on experimental data. In this work, Isis-3D calculations were performed to simulate the conditions of three experiments that measured the temperature response of a 4.66 m diameter culvert pipe located at the leeward edge of 18.9 m and 9.45 m diameter pool fires in crosswinds with average speeds of 2.0, 4.6, and 9.5 m/s. Isis-3D accurately calculated the time-dependent temperatures in all three experiments. Accelerated simulations were performed in which the pipe specific heat was reduced compared to the measured value by a factor of four. This artificially increased the speed at which the pipe temperature rose and allowed the simulated fire duration to be reduced by a factor of four. A 700 sec fire with moderately unsteady wind conditions was accurately simulated in 10 hours on a standard workstation.

A Study of Heat Transfer Calculation Method of Reactor Vessel Metallic Insulation

2014 ◽  
Author(s):  
Yan Dapeng ◽  
Ying Luo
Keyword(s):  
Heat Transfer ◽  
Computational Model ◽  
Complex Geometry ◽  
Effective Conductivity ◽  
Radiation Heat Transfer ◽  
Reactor Vessel ◽  
View Factor ◽  
Main Mode ◽  
Modified Model ◽  
Test Result

Metallic insulation is commonly used in reactor vessel because of its resistance to radiation and corrosion. Since the main mode of heat loss of reactor vessel is thermal radiation, the ability to prevent radiation heat transfer is important for metallic insulation. But the thermal conductivity of metallic insulation is difficult to calculate owing to their complex geometry. This article uses FLUENT 14.0 to obtain the important parameter “view factor”, and then develops a computational model of effective conductivity of metallic insulation. Heat transfer test of metallic insulation was done, and the numerical simulation of metallic insulation was also performed. Based on results of test and simulation, the computational model is modified. The modified model can fit the test result better. Based on the modified model, the effective conductivity of metallic insulation increases with the increase of temperature of hot side and cold side, among which the temperature of hot side influences more. And when the temperature is high, the effective conductivity increases much faster.

Fast Running Pool Fire Computer Code for Risk Assessment Calculations

2003 ◽  
Author(s):  
Miles Greiner ◽  
Ahti Suo-Anttila
Keyword(s):  
Heat Transfer ◽  
Reaction Rate ◽  
Volume Fraction ◽  
Radiation Heat Transfer ◽  
Soot Volume Fraction ◽  
Computer Code ◽  
Pool Fire ◽  
Temperature Measurements ◽  
Radiation Heat ◽  
Transportation Risk

The Isis-3D computational fluid dynamics/radiation heat transfer computer code was developed to simulate heat transfer from large fires to engulfed packages for transportation risk studies. These studies require accurate estimates of the total heat transfer to an object and the general characteris tics of the object temperature distribution for a variety of fire environments. Since risk studies require multiple simulations, analysis tools must be rapid as well as accurate. In order to meet these needs Isis-3d employs reaction rate and radiation heat transfer models that allow it to accurately model large-fire heat transfer even when relatively coarse computational grids are employed. In the current work, parameters for the reaction rate model were selected based on comparison with soot volume fraction and temperature measurements acquired in a recent 6 m square pool fire under light wind conditions. The soot volume fraction Isis-3D uses to define the edge of the optically thick fire was determined using temperature measurements of a pipe engulfed 20-m-diameter pool fire with a steady 9.5 m/s crosswind. Accelerated simulations, in which the specific heat of the engulfed pipe was reduced by a factor of twelve below the measured values, reproduce the temperature data in the 11-minute crosswind fire using only 3.5 hours on a standard desktop workstation.

Integrity Analysis of Electrical Penetration With Intense Radiation Heat Transfer by Hydrogen Diffusion Flame

2017 ◽  
Author(s):  
Gaofeng Huang ◽  
Kun Zhang ◽  
Jiayun Wang
Keyword(s):  
Heat Transfer ◽  
Diffusion Flame ◽  
Hydrogen Diffusion ◽  
Hot Spot ◽  
Radiation Heat Transfer ◽  
Hydrogen Release ◽  
Heat Radiation ◽  
View Factor ◽  
Containment Vessel ◽  
Integrity Analysis

While hydrogen release into large compartment from confined compartment, hydrogen diffusion flame is easy to occur. There is intense heat radiation effect on electrical penetration from diffusion flame. Aim to evaluate the influence of diffusion flame on electrical penetration, systematic method is constructed, including computing view factor of electrical penetration, assessment of hot spot of containment vessel and research of heat transfer for electrical penetration. Research results give theory basis for determining location of venting which can generate hydrogen diffusion flame. The method can be extended to use in the influence evaluation of personnel hatch and equipment hatch in the containment vessel.

A Numerical Investigation of Ray Tracing Method in a View Factor Calculation Procedure for Zonal Radiation Heat Transfer in Complex Systems

2009 ◽  
Author(s):  
German Malikov ◽  
Vladimir Lisienko ◽  
Roman Koptelov ◽  
Jakov Kalugin ◽  
Raymond Viskanta
Keyword(s):  
Heat Transfer ◽  
Ray Tracing ◽  
Direct Method ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
View Factor ◽  
Radiation Heat ◽  
Zonal Method ◽  
Metallurgical Furnaces

In this paper a variety of well known computer graphics algorithms (Binary Spatial Partitioning-BSP, Bounding Box-BB, and direct method of sequential search) for ray tracing are studied numerically in the context of the view factor calculations for the zonal method of radiation heat transfer analysis in complex industrial furnace geometries. The paper reports on a modified BSP algorithm which takes into account the specific types of obstructions and their arrangement in different types of metallurgical furnaces. The modified algorithm enhances the ray tracing calculations by two to three orders of magnitude. An universal algorithm to obtain an intersection with a polyhedron obstruction is developed. The method is tested for simple three dimensional and complex furnace geometries.

Eight Surfaces of Radiation Heat Transfer Network Model Development

2013 ◽  
Vol 391 ◽  
pp. 191-195 ◽  
Author(s):  
Ummi Kalthum Ibrahim ◽  
Ruzitah Mohd Salleh ◽  
W. Zhou
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Radiative Heat ◽  
Radiation Heat Transfer ◽  
Model Development ◽  
Transfer Model ◽  
View Factor ◽  
Radiation Heat

This paper deals with the numerical solution for radiative heat transfer within a heated six wall surfaces baking oven, baking tin surface and bread surface. The radiation heat transfer model is constructed by adopting a radiation network representation analysis. The analysis applies view factor and radiosity in determining the radiation rates for each surface in the oven. The amount of radiation heat, q and temperature, T variables are equivalent to electric current and voltage, respectively. Finite difference method coupled with Gauss-Seidel iteration was selected to solve the equations involved in the analysis. Even though this method is tedious and intractable for multiple surfaces, but it would seem to be the most accurate and suitable approach for radiation analysis in the enclosure.

Pool Fires and Radiant Ignition Capability

1999 ◽  
Author(s):  
David G. Lilley
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Real World ◽  
Radiation Heat Transfer ◽  
Primary Reason ◽  
Pool Fires ◽  
Fire Growth ◽  
Radiation Heat ◽  
Present Contribution ◽  
Time Required

Abstract Radiation heat transfer is a primary reason for fire growth. Experimental data are needed to clarify the ignition potential and time required to ignite a particular “target” second item. The objective of the present contribution is to clarify how the size and material of a pool fire determine ignition distance capability, and exemplify realistic calculations related to real-world situations.

Gas-Particle Flow Within a High Temperature Solar Cavity Receiver Including Radiation Heat Transfer

1987 ◽  
Vol 109 (2) ◽  
pp. 134-142 ◽  
Author(s):  
G. Evans ◽  
W. Houf ◽  
R. Greif ◽  
C. Crowe
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Particle Interaction ◽  
Computer Code ◽  
Solid Particles ◽  
Forced Flow ◽  
Discrete Ordinates ◽  
Temperature Profiles ◽  
Thermal Coupling ◽  
Solar Receiver

A study has been made of the flow of air and particles and the heat transfer inside a solar heated, open cavity containing a falling cloud of 100-1000 micron solid particles. Two-way momentum and thermal coupling between the particles and the air are included in the analysis along with the effects of radiative transport within the particle cloud, among the cavity surfaces, and between the cloud and the surfaces. The flow field is assumed to be two-dimensional with steady mean quantities. The PSI-Cell (particle source in cell) computer code is used to describe the gas-particle interaction. The method of discrete ordinates is used to obtain the radiative transfer within the cloud. The results include the velocity and temperature profiles of the particles and the air. In addition, the thermal performance of the solid particle solar receiver has been determined as a function of particle size, mass flow rate, and infrared scattering albedo. A forced flow, applied across the cavity aperture, has also been investigated as a means of decreasing convective heat loss from the cavity.

Optimum Spacing of Vertical Parallel Plates for Maximum Radiation Heat Transfer

2014 ◽  
Author(s):  
Hanry Issavi ◽  
Fred Barez ◽  
Younes Shabany ◽  
Ernest Thurlow
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Radiation Heat Transfer ◽  
Convection Heat Transfer ◽  
View Factor ◽  
Parallel Plates ◽  
Radiation Heat ◽  
Parabolic Distribution ◽  
Optimum Spacing ◽  
Exact Correlation

The reliability of the majority of electrical and electromechanical systems depends on their ability to dissipate heat generated by their internal components. Application of parallel plates for cooling electronic equipment is one of the most common methods of heat dissipation through convection and radiation. Others have investigated the optimum spacing between vertical plates for the case of maximum natural convection heat transfer. The goal of this study was to determine the optimum spacing for the maximum radiation heat transfer. Analytic calculations were carried out to determine the optimum spacing. A mathematical interpolation was used to simplify the view factor correlations and from this an exact correlation was obtained to determine the optimum spacing for radiation heat transfer. It was concluded that for a known plate surface area, the optimum spacing for the maximum radiation decreases when the ratio of height over length of the plates increases. For fixed geometric parameters, the optimum spacing for radiation will display a skewed parabolic distribution when the surface emissivity of the plates was increased.

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