QUANTIFICATION OF MASS FLOW RATE OF FIRE PLUME AND DOWNWARD-MOVING GASES

A study on smoke behavior in a compartment with sprinkler system activation Part 2

Abstract

It is necessary to determine quantitatively a mass flow rate of downward-moving gases penetrated the boundary between upper and lower layer and fire plume in order to calculate smoke behavior in a compartment with sprinkler activation. A calculating formula of the mass flow rate of fire plume and downward-moving gases was found using a suggested gas analysis in the previous report of this study. The mass flow rate of downward-moving gases is m_E/m_SP=0.003(ρ_a-ρ_S)^-1 in inverse proportion to density differences between upper layer and lower layer. The mass flow rate of fire plume was corrected by the location of the virtual source in the sprinkling. The effective virtual source with sprinkler activation is Z_SP=0.04(ρ_a-ρ_S)^-1 in inverse proportion to density differences between upper layer and lower layer. As a result, the mass flow rate of fire plume was proportional to Q_f^2/3(Z_S+Z_SP)^5/3 and given by m_p=0.03 Q_f^2/3(Z_S+Z_SP)^5/3+m_E.