Experimental study on the effect of mechanical ventilation conditions and fire dynamics on the pressure evolution in an air-tight compartment
Résumé
The paper presents a comprehensive set of experiments on the effect of mechanical ventilation conditions and
fire dynamics on temporal pressure evolution in a reduced-scale, air-tight and mechanically-ventilated enclosure.
A square propane burner with flow controller imposes a quadratic fire growth followed by a steady-state (0.1
or 0.2 g/s) and then a quadratic decay phase. Eight tests are discussed with different ventilation conditions in
terms of flow resistances and initial ventilation flow rates ranging from 12 to 40 m3/h, corresponding to air renewal
rates of 6.4–21.3 h−1.
The pressure evolution is characterized by an over-pressure peak (up to 900 Pa) followed by a quasi-steady
state and then, an under-pressure peak (up to −760 Pa). The pressure variation is due to the mechanical effect
(i.e., ventilation configurations), while also influenced by thermal effects. The pressure amplitudes increase with
ventilation resistances. Both the total network resistance and individual resistances in admission and extraction
ducts are important for the pressure variation. The enhancement and reduction of ventilation flow rates depend
on both the fire-induced pressure and ventilation resistances. Experimental results show that the mechanical effect
does not strongly affect gas temperatures.
Domaines
Sciences de l'ingénieur [physics]
Origine : Fichiers produits par l'(les) auteur(s)
