This discussion shows how to build a two compartment scenario. We start with a simple fire in a single compartment, add a second object, then another room, and finally a third object in the second room. This latter shows the capability to assess the effect that geometry and object properties has on fire spread. The following datafile excerpts do not include simulation or environment keywords.
The results are sensitive to both the geometry and topology of the scenario. As we will see, interaction between the flow field and the positions of the fires can alter the results quite dramatically.
First the single room (kitchen). The datafile (TwoCompartmentsStep1) lays out a single compartment scenario with a grease fire. The door to/from the kitchen is open as would be expected when we add the next compartment.
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The data to do this are
!!Compartment keywords!!
COMPA,Kitchen,3.6,2.4,2.4,0,0,0,GYPSUM,OFF,GYPSUM
!!
!!vent keywords
!!
HVENT,2,1,1,0.6,2,0,1,0.9,0,2,1
!!
!!fire keywords
!!
OBJECT,GreaseFire,1,0.3,0.4,1,1,1,0,0,0,1
The is not a large fire but does give rise to a high upper layer temperature early in the simulation. Then we add a cabinet adjacent to the stove (TwoCompartmentsStep2). The cabinet is a typical kitchen cabinet of laminated oak with a thin veneer coating. To do this, add
OBJECT,Cabinet,1,1,0.4,2.2,1,2,323.15,0,0,1to the scenario.
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Note the position of the cabinet. As typical in a kitchen, there will be a wood cabinet above and next to the stove. The position in the upper layer (soon after the grease fire has started) changes the outcome significantly as the geometry changes. Looking at the heat release rate and upper layer temperature
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Once the cabinet is ignited (by temperature), the temperature in the upper layer rises quickly and the oxygen decreases rapidly. Now add a second compartment (dining room, TwoCompartmentsStep3
COMPA,Living Room,6,2.4,2.4,3.6,0,0,GYPSUM,OFF,GYPSUMThe door from the kitchen automatically becomes the door to the living room. We also add a door to the the outside (or next compartment), and a leakage path to simulate the reality of structures which are not tightly sealed
HVENT,2,3,1,1,0.02,0,1,0.7,0,2,1HVENT,2,3,2,1,2,0,1,0.7,0,2,0
This leads to a significantly different outcome.
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The change arises from changes in the layer height and oxygen concentration arising from the more complex interaction of compartments and flow (the green line is the soffit height),
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and the oxygen concentration in the layer. Finally, add a third fire (TwoCompartmentsStep4) in the living room
OBJECT,DiningTable,1,1,0.4,2.2,1,2,323.15,0,0,1.
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Which yields heat release and temperature curves of
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As can be seen from the oxygen concentration and layer height in the kitchen which changes the nature of the fire.
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This is a simple example of building a two compartment scenario, step by step. Each of the scenarios is available by clicking the appropriate key word. The objects are Grease fire, Cabinet and Dining Table
