Numerical Modeling of Compartment Fires: Ventilation Characteristics and Limitation of Kawagoe's Law

Kawagoe's Law is an essential correlation in compartment fire research, which defines the relationship between the ventilation factor and maximum fuel burning of the compartment. Although this law has been widely used, there is still a lack of numerical validation and knowledge on the limiting conditions of its application. In this paper, a numerical study is conducted under full-scale compartment fire with different opening sizes and gas fuel supply rates using the LES model for validating Kawagoe's Law. The mass flow rate of inflow through the opening and the indoor heat release rate is focused during the numerical validation. Numerical results show that the inflow rate and indoor heat release rate comply well with Kawagoe's Law under ordinary openings with a small aspect ratio. However, Kawagoe's Law becomes less valid for openings with large aspect ratios and small-gap openings. The jet flame was observed in the case of openings with large aspect ratios under a high fuel supply rate. For compartment fires with small gaps, a breathing process, i.e., the periodical suppression and revitalization of the fire, is modeled. This work provides practical guidance for modeling compartment fires and paving the way for constructing a numerical compartment fire database.

Automated summary

In this paper, the validity of Kawagoe's Law in compartment fire is validated through numerical study. The results show that Kawagoe's Law holds true for ordinary openings, but becomes invalid for openings with large aspect ratios and small gaps. The study also reveals the occurrence of jet flame and the breathing process in compartment fires with small gaps.