Table of Contents
To simulate a surface made of heat-conducting solids or a fuel you must specify a material that describes certain thermal properties and pyrolysis behavior. PyroSim offers two categories of materials: solid materials and liquid fuels.
To create a new material, you can use the Edit Materials dialog. On the Model menu, click Edit Materials....
Examples of solid materials include brick, gypsum board, and upholstery. To create a solid material:
In the Edit Materials... dialog, click New...
In the Material Name box, type the name of the new material
In the Material Type box, select Solid
Click OK
After following these steps, a default solid material will be created. Text entered in the Description box will not affect the simulation, but will preserved in the FDS input file using the FYI field of the material. Including a description of the material is recommended.
The Thermal Properties tab provides the following options:
| Parameter | Description |
|---|---|
| Density | The material's density. |
| Specific Heat | The material's specific heat. Specific heat can be specified as a function of temperature. |
| Conductivity | The material's heat conductivity. Conductivity can be specified as a function of temperature. |
| Emissivity | The material's emissivity. A value of 1.0 corresponds to maximum radiation. |
| Absorption Coefficient | This coefficient refers to the depth over which thermal radiation can be absorbed. |
The Pyrolysis tab provides options to set the heat of combustion and add reactions that will be used to govern how the material burns. Each material can have a maximum of 10 reactions. To add a reaction, click Add.... This will open a dialog to edit the new reaction. It provides the following options:
On the Rate tab:
| Parameter | Description |
|---|---|
| Achieve reaction rate of | The reaction rate at a given temperature. |
| at | The temperature at which the given reaction rate will occur. |
| A (Pre-exponential Factor) | (parameter shown in equation) |
| E (Activation Energy) | (parameter shown in equation) |
| Mass Fraction Exponent | (parameter shown in equation) |
| Exponent | (parameter shown in equation) |
| Value | (parameter shown in equation) |
On the Byproducts tab:
| Parameter | Description |
|---|---|
| Heat of Reaction | Heat yield of this reaction. This must be a positive number. |
| Endothermic/Exothermic | Specifies if the heat yield is endothermic or exothermic. |
| Fuel Vapor Yield | The mass fraction of yield that will become fuel vapor. |
| Water Vapor Yield | The mass fraction of yield that will become water vapor. |
| Residue Yield | The mass fraction of yield that will become residue. If there is only one material defined in PyroSim, this option will not be available. |
| Residue | The material that will be used to represent the residue. If there is only one material defined in PyroSim, this option will not be available. |
Examples of liquid fuels include kerosene and ethanol. To create a liquid fuel:
In the Edit Materials... dialog, click New...
In the Material Name box, type the name of the new material
In the Material Type box, select Liquid Fuel
Click OK
After following these steps, a default solid material will be created. Text entered in the Description box will not affect the simulation, but will preserved in the FDS input file using the FYI field of the material. Including a description of the material is recommended.
The thermal properties tab for liquid fuels is identical to the thermal properties tab solid fuels (see Section ).
The Pyrolysis tab provides the following parameters:
| Parameter | Description |
|---|---|
| Heat of Vaporization | Heat yield when this liquid fuel is converted to gas. This must be a positive number. |
| Endothermic/Exothermic | Specifies if the heat yield is endothermic or exothermic. |
| Fuel Vapor Yield | The mass fraction of yield that will become fuel vapor. |
| Water Vapor Yield | The mass fraction of yield that will become water vapor. |
| Residue Yield | The mass fraction of yield that will become residue. If there is only one material defined in PyroSim, this option will not be available. |
| Residue | The material that will be used to represent the residue. If there is only one material defined in PyroSim, this option will not be available. |