Wind-tunnel experiments on atmospheric heavy gas dispersion: Metrological aspects

Vidali, Cristina; Marro, Massimo; Correia, Horacio; Gostiaux, Louis; Jallais, Simon; Houssin, Déborah; Vyazmina, Elena; Salizzoni, Pietro

doi:10.1016/j.expthermflusci.2021.110495

Cited by 6 publications

(1 citation statement)

References 39 publications

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“…The released air–helium mixture and its seeding are controlled by means of three flow meters (Alicat Scientific Inc., MC-Series, USA). This type of flow meter has an error on the flow rate that does not exceed % if compared with classical volumetric counters (Nironi et al., 2015; Vidali et al., 2022). The air and helium flow rates can be varied up to 500 l min (precision 2.5 l min) and 200 l min (precision 1 l min), respectively, while the flow rate of the air with nebulised oil can reach a maximum discharge of 20 l min (precision 0.1 l min).…”

Section: Experimental Methodologymentioning

confidence: 99%

Measurements and scaling of buoyancy-induced flows in ventilated tunnels

Salizzoni

Peruzzi

Marro

et al. 2023

Flow

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We investigate the ventilation conditions required to control the propagation of smoke, produced by a tunnel fire, in the presence of two inertial forcings: a transverse extraction system and a longitudinal flow. For that purpose, we performed a series of experiments in a reduced-scale tunnel, using a mixture of air and helium to simulate the release of hot smoke during a fire. Experiments were designed to focus on the ventilation flows that allow the buoyant release to be confined between two adjacent extraction vents. Different source conditions, in terms of density and velocity of the buoyant release, were analysed along with different vent configurations. Experiments allowed us to quantify the increase of the extraction velocity needed to confine the buoyant smoke, overcoming the effect of an imposed longitudinal velocity. Vents with a rectangular shape, and spanning over the whole tunnel width, provide the best performance. Finally, we studied the stratification conditions of the flow, individuating four regimes. Interestingly, when the stratification conditions fade out, as both the longitudinal flow and vertical extraction flows increase, the flow dynamics becomes almost independent of the forcing induced by the presence of buoyant smoke, which eventually acts as a passive scalar transported by the flow.

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