The Smoke Layer Descending Simulation in a Small Space by Using Two-Layer Zone Model

• Main Authors: Shiu, Bing-Kai, 徐秉楷
• Other Authors: Chen, Jun-Xun
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/09547896562232926765

碩士 === 國立交通大學 === 機械工程系所 === 101 === The main purpose of this study is to develop the two-layer zone model suit for small space and use it to analyze the fire place. Because of the low floor and the huge heat release of accumulative combustible, there is some difficult when using「The Building of Fire Safety and Evacuation Verification technical manuals」to verify the safety of evacuation in small space. So we adopt the two-layer zone model to verify whether the evacuation is safe or not. The main purpose of develop this program is to predict the fire place in proper conditions and compare the results with FDS、「The Building of Fire Safety and Evacuation Verification technical manuals」and some experiments, to verify the reliability of the program. In this research, we’ll take the condition of fire place into consideration by means of programming, and develop relevant formulae so as to coordinate the condition of fire place. By inputting some conditions relevant to small space and heat release, the analysis of fire place will be launched immediately. By verifying the program results with some related experiments, the results show when we take the heat radiation into account the result can get closer to the experimental temperature distribution in natural condition. The heat radiation is a really important factor. There are two cases studies: (a) The some space volume but in different ratio of floor area and floor height in no vent flow condition(2) The some vent area but in different ratio of breadth and height in natural flow condition. By the case study one, the higher the room floor height ,the faster the smoke descending rate is in the same room volume situations, because of the higher room floor height, the smoke generation rate is higher. Finally, the case of two shows that the opening rate and the lower edge of the opening have a great influence on smoke exhaust Finally, by comparing to some experiments, here are some conclusions about the effect of parameters in two-layer zone simulation. (1)Heat radiation have a great influence on smoke layer temperature; (2)The pressure difference between indoor and outdoor space is the main driving force of natural flow (3) The performance of natural flow are affected by the occupancy of the vent and the lower edge of vent.