This link is an efficient way to model a basic fire that affects both the temperature and atmospheric content of the node that it is connected to.

This link models a fire by adding heat, CO2, H2O and optional trace compounds, and removing O2 from the node. The fire is controlled by a desired heat output, and the fluid and trace compound flow rates are proportional to the active fire heat rate. The fire can automatically extinguish when the node partial pressure of O2 drops below a configurable value.

This link has one port that must be attached to a gas phase node, such as a atmospheric volume. Connection to any other phase node will result in an initialization error.

Port Connection Rules (These are limitations on the port connection to nodes that the link enforces in run-time):

• Must be connected to a gas phase node.
• Fluid types GUNNS_O2, GUNNS_H2O, and GUNNS_CO2 must all be present in the network.

Other Rules (These are extra rules you should always try to follow):

• The sum of mFireCO2ProductRate and mFireH2OProductRate should be greater than mFireO2ConsumpRate. Otherwise, any configured trace compounds fire products will not flow into the node properly.
• Take care to provide sufficient volume in the attached or nearby nodes to recieve the fluid products, otherwise instabilities can result.

Configuration Data Parameters:

• fireO2ConsumpRate (default = 0.0 (kg/J)): This determines the oxygen mass flow rate per unit of malfFireHeat. Positive values indicate a flow of oxygen out of the node. If trace compounds are used (see below), then this value should be lower than the sum of fireCO2ProductRate and fireH2OProductRate. Otherwise, the trace compounds will not work properly.
• fireCO2ProductRate (default = 0.0 (kg/J)): This determines the carbon dioxide mass flow rate per unit of malfFireHeat. Positive values indicate a flow of carbon dioxide into the node.
• fireH2OProductRate (default = 0.0 (kg/J)): This determines the water vapor mass flow rate per unit of malfFireHeat. Positive values indicate a flow of water vapor into the node.
• fireMinReqO2 (default = 0.0 (kPa)): The minimum partial pressure of O2 required for the fire to continue to burn. The model will automatically disable the malfunction when the node partial pressure of O2 drops below this value. A typical example value for fires is 10.34 kPa. To disable this feature, leave this value zero.
• mFireTraceCompoundRates (Trick Input File only): The production rates (kg/J) of trace compounds per unit of malfFireHeat. This is optional. The default value is null, which produces no trace compounds in the fire. If trace compounds are desired, use the Trick Input File to override this term to point to your array of desired rates, noting the following rules:
  • Create an array of doubles in the input file and set the trace compound production rates in the array.
  • The order of the values in the array match the order of the trace compounds in the network.
  • The number of elements in the array must equal the number of trace compounds in the network.
  • Set the link's mFireTraceCompoundRates member, noting the following syntax, where rates is your input file array of trace compound production rates:
    • simObject.network.netConfig.linkName.mFireTraceCompoundsRates = rates

Input Data Parameters:

• malfBlockageFlag (default = false): Initial state of the blockage malfunction activation flag. This malfunction reduces the fire malfunciton's actual flow rates to/from the node.
• malfBlockageValue (default = 0.0, must be (0-1)): Initial state of the blockage malfunction activation value. A value of 0.0 is the same as no blockage at all, and 1.0 completely blocks all flows.
• malfFireFlag (default = false): Initial state of the fire malfunction activation flag.
• malfFireHeat (default = 0.0 (W), and non-zero magnitudes should be kept between E-15 and E+15): Initial state of the fire malfunction heat value. This is the heat added to the node, and what scales all fluid rates, when the fire is active.

• Pressure Stability: This link is susceptible to the same stability problems in a network as the fluid source link. See the description of this problem in GunnsFluidSource.
• Temperature Instability: This link is susceptible to the same stability problems in a network as the fluid heater link. See the description of this problem in GunnsFluidHeater.
• Reversal of Trace Compounds Direction: Due to a limitation of GUNNS fluid and trace compounds flow transport, the direction of trace compounds flow will reverse if the fire's O2 consumption rate nears or exceeds the total H2O & CO2 production rate. There is not yet a reliable workaround.

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