• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.790-793
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• 2009

In the case of projection type display, it needs to use the screen in order to project the image clearly and wide viewing angle. We have been developing the step in type display system using the smoke screen. However, the image with smoke screen was flickered by gravity and air flow. Then we considered to reduce the flicker of the image and we found that flicker can be reduced and viewing angle becomes more large. This time we report the large viewing angle step in type display system using screen made up with very small particle size smoke and flow controlled nozzle. Hence, at first we considered the most suitable particle for the screen and then the shape of screen and then we constructed the array of flow controlled smoke screen. By the results of experiment we could get considerably high contrast flicker-less image and get the viewing angle more than $60^{\circ}$ by this flow controlled nozzle attached new type smoke screen and make clear the efficiency of this method.

• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.50-54
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• 2006

A fire in a subway station platform, completely isolated by screen doors, was numerically simulated to investigate problems in smoke control and find their countermeasures. A part of the platform, $40m{\times}5m$ floor and 3 m high, and a fire of 1 MW were considered, and the smoke extraction system was assumed to start operation at the onset of the fire. For three different values of the exhaust air flow rate, 0.1, 2, and $4m^3/min-m^2$, the distributions of temperature, concentrations of soot and carbon monoxide, and those of visibility were compared. The time-variations of the number of randomly distributed particles in the space were also investigated for the air flow rates to see the efficiency in smoke control. It was shown that smoke control takes time by lack of air supply. It was also confirmed that air supply from the railway to the platform at emergency is needed so that smoke is able to be controlled efficiently, and that opening the doors at the both ends of the platform is desirable until the fire is completely extinguished.