Purpose This paper aims to determine the halon concentration time-evolution inside an aircraft cargo compartment to design fire extinguishing systems. Design/methodology/approach A fire suppression system is numerically simulated using the lumped parameter approach. Findings The halon volumetric concentration, halon and air mass fluxes and the cargo compartment pressure are numerically calculated. It also determines the time to halon concentration to achieve the fire suppressant value (high pressure bottle) as well as its inerting volumetric concentration (low pressure bottle). Research limitations/implications In the lumped parameter approach, the dependent variables of interest are a function of time alone, and its spatial distribution is neglected. Practical implications This study predicts the fire extinguishing agent behavior aiming to satisfy cargo compartment certification requirements. Originality/value This paper uses a simplified methodology, but it represents a very useful tool during the preliminary stages of the aircraft fire suppression systems design.

This work focuses on a numerical study of a diesel engine valve ports steady-state compressible flow to calculate the mixing effects due to the presence of the filling and spiral intake ducts. These valve ports have an important role in engine charge exchange (exhaust and intake mechanisms), air-fuel mixture and combustion processes. Diesel engine industry developed a stationary bench flow tests which has been very useful to improve the preliminary design of valve ports. In this bench methodology, a stationary airflow is induced through valve ports by a exhaust fan where pressure drops and swirl flow patterns are measured maintaining a fixed valve aperture. At this context, the present CFD (Computational Fluid Dynamic) work intends to show fluid flow patterns and to calculate the Swirl number induced by the secondary flow. A 3D turbulent steady compressible flow is solved employing a finite volume technique with a density based approach.