# FDS coding material

Consider a cubic-shaped enclosure that is 1 m high, 1 m wide and 1 m deep (0 ≤ x ≤ 1 m; 0 ≤ y ≤ 1 m; 0 ≤ z ≤ 1 m). The enclosure features two openings. The first opening is located in the middle of the room at floor level; it is square-shaped and has a size equal to 0.4 × 0.4 m2 (0.3 ≤ x ≤ 0.7 m; 0.3 ≤ y ≤ 0.7 m; z = 0 m). The second opening is located at the bottom of one of the vertical walls; it is also square-shaped and has a size equal to 0.6 × 0.6 m2 (x = 1 m; 0.2 ≤ y ≤ 0.8 m; 0 ≤ z ≤ 0.6 m). The floor opening acts as an inflow vent and injects fuel into the enclosure, initially filled with air. The vertical opening acts as an inflow/outflow vent. The fuel is propane; its injection mass flow rate is prescribed and such that the fire size is 80 kW. The compartment solid walls are assumed to be adiabatic. We focus here on the general problem of measuring gas temperatures in fire configurations and propose to illustrate this problem by using the thermocouple model available in FDS. Place thermocouple and gas temperature sensors along the center line of the fire at elevations z = 0.1, 0.5 and 0.9 m. Run a FDS simulation for 30 s; use a 2 cm grid resolution. Plot the time variations of the thermocouple and gas temperatures; discuss observed discrepancies, if any. Consider now that the fire is open rather than confined (remove all walls except for the floor). The fire size is still 80 kW. Run a new FDS simulation. Plot the time variations of the thermocouple and gas temperatures (along the center line and at elevations z = 0.1, 0.5 and 0.9 m); discuss observed discrepancies, if any.