Studies on the Delay of Smoke Detector Alarm in Underground Engineering
Di Zhang,Xiao-Ping Miao,Feng Jiang +2 more
- pp 462-465
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TLDR
Based on numerical simulation, the delay of smoke detector alarm was studied in this article, where the authors analyzed the impact of the smoke detector location and air supply velocity on the detector alarm performance.Abstract:
Based on numerical simulation, the delay of smoke detector alarm was studied in this paper. The a ir velocity fields and smoke concentrations were introduced in to help to analyze the impact of detector location and air supply velocity on the detector alarm performance. The results revealed that the position of smoke detector had a great influence on the alarm time. Inappropriate installation position delayed the alarm; m eanwhile, the delay was aggravated with larger air inlet velocity. It is of great significance to study the pattern of fire and smoke spread to determine the feasibility of a fire test system. I ntroduction In the underground engineering, the smoke detector is usually installed in the middle position of the roof. And the detector performs well under no wind conditions ( 1 ) . However, when the ventilation and air conditioning system is running, the airflow organization would be different in the room. The smoke would spread with the airflow in the early stage of fire. The smoke detectors can not sent the alarm information timely, w hich would increase the risk of fire (2)(3) . The ventilation and air conditioning system was different according to the location and direction of the wind pi pe. The mounting position of smoke detector should relate to the different air supply mode. This paper s tudied the smoke spread characteristic of two typical underground engineering air supply modes based on t he numerical simulation. The conclusion can guide the mounting position of smoke fire detector.read more
References
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A numerical study on smoke movement in longitudinal ventilation tunnel fires for different aspect ratio
Sung Ryong Lee,Hong Sun Ryou +1 more
TL;DR: In this paper, numerical simulation was carried out to analyze the effect of the aspect ratio on smoke movement in tunnel fires using FDS 3.0, which confirmed the possibility of application of FDS code to tunnel fires.
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Particulate Entry Lag In Spot-type Smoke Detectors
TL;DR: In this article, a two-parameter model is presented to model the time-lag of spot-type smoke detectors with a characteristic time proportional to the inverse of velocity and a constant of proportionality defined as a characteristic length.
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CFD Fire Simulation Using Mixture Fraction Combustion and Finite Volume Radiative Heat Transfer
TL;DR: In this paper, a computational fluid dynamics (CFD) model of fire and smoke transport is described, where combustion is represented by a single conserved scalar known as the mixture fraction.