撒水頭作動時間的實尺寸分析

Investigation of Thermal Response of Glass Bulb Sprinklers in a Full-Scale Room

本研究針對密閉式撒水頭於火場之作動時間進行實驗與探討，於6m×5m 之實尺寸房間進行密閉式撒水頭作動時間實驗與分析影響撒因素，並使用FDS（Fire Dynamics Simulator）進行比較分析。在本研究中，火源位置設定為火源位於房間中央區域、火源緊靠於壁面以及火源位於房間角落等三類。實驗結果顯示撒水頭作動時間與流場特性有關，而流場特性又與壁面、火源與撒水頭距離以及通風口有關。實驗過程發現火源緊靠壁面時，火焰高度會較火源位於房間中央區域時高，且煙氣的上升速度增快，而致使撒水頭作動時間縮短。若火源位於房間角落，則其對於火場的影響會比壁面效應更大，且撒水頭作動時間最快。FDS 模擬實驗屋內昇溫曲線與實驗值比對發現兩者間存有偏差。經熱電偶靈敏度實驗結果，發現在撒水頭作動時，實驗屋所量得的溫度會與模擬預測火場溫度約低30~40℃。若摒除熱電偶靈敏度影響，整體而言FDS 對此實驗所進行的模擬相當準確，而且溫度的變化趨勢也與實驗相當一致。

With regard to the activation of the automatic fire sprinklers, a series of tests were carried out by using a gas burner sat at various locations in a full-scale room. At the same time, Fire Dynamics Simulator was used to predict the temperature field of the tested room. The gas burner was placed in three different locations. When the burner was placed against the wall, the height of flame was higher and the movement of smoke was faster, and the activation time of the sprinkler was reduced. The effect of corner was greater than the effect of wall, so that the activation time of the sprinkler was the shortest when burner was at the corner. The activation time was longest when the gas burner was placed in the center of the room. From comparisons of the experimental and predicted data, it was found that the trends of temperature variations from experiments and FDS simulations were similar, but there exited a temperature difference of 30~40℃ in between. This temperature difference was caused by the response time of thermocouples justified by the sensitivity test of thermocouples.