Interaction Between a Plume Ceiling Jet and the Flow Driven by a Jet Fan - a Study for Smoke Control

Abstract

An experimental study aimed at smoke control by means of impulse jet fans in covered car parks is reported. This study includes measurements of the isothermal velocity field induced by two parallel wall jets, and measurements of the velocity and temperature fields of a ceiling jet originated from a pool fire, with or without the influence of the wall jets. The velocity and temperature fields measured during the tests with the pool fire without ventilation show that Alpert’s analytical model fits well the experimental data. The measurements for the pool fire with the wall jets reveal that the heat release rate is incremented, while the smoke temperature decreases and the smoke layer thickness increases due to the jet fans. The analysis of the isothermal velocity field of the two parallel wall jets and the velocity field from the pool fire without the influence of the walls jets suggests that it is possible to estimate the region where the smoke stops from these two configurations. This analysis is corroborated by observations made during the experimental work. This information is relevant to help designers to select the location of the impulse fans in covered car parks.