Flow analysis of tall spaces in natural smoke extraction systems

[[abstract]]高層建築體型巨大、功能複雜，人員物品都相當集中，如果釀成火災，會造成嚴重的人員傷亡和經濟損失。高層建築火災中的煙氣更是危害生命的重要因素。本文研究主要目的是利用紋影光學系統可視化方式探討挑高建築單一開口、雙開口以及不同補氣、進氣口位置，造成熱氣流的分布。 本研究以6 4cm(W)x0 8cm(L)x8cm(H) 玻璃模型進行縮小尺度實驗，在玻璃兩邊各開1 6cm進氣口、0 5cm補氣口、0 8cm出氣口(包含上方)，首先探討在玻璃內部雙出口、左方出口以及上方出口三種形式，觀察挑高建築發生火災發生時自然排煙在不同開口熱氣流情況。並以三種出氣口分別搭配遮擋補氣口和進氣口對自然排煙是否有影響及熱氣流變化，再搭配紋影光學法來驗證。 結果顯示，在無遮擋進氣口和無遮擋補氣口的情況下，由於左出口和上方開口皆有高溫氣流的蓄積以及底層溫度升高。然而雙出口既沒有高溫氣流蓄積底層溫度也處於室溫狀態，對於火災之人員是相對安全的。在遮擋進氣口和無遮擋補氣口的情況下，會快速使高溫煙氣蔓延整個模型內部，底層溫度快速升高。其中由雙出口的案例為更加快速，對於人員安全更加危險。[[abstract]]High-rise buildings of great size functional complexity personnel items are quite concentrated if causing a fire it will cause serious casualties and economic losses High-rise building fire smoke is an important factor in life-threatening The main purpose of this study was to investigate the use of high-ceilinged building a single opening Schlieren optical system having a visual way with two openings and different qi inlet position resulting in the distribution of hot air In this study 6 4cm (W) x0 8cm (L) x8cm (H) glass model downscaling experiment in the glass on both sides of the opening of the intake port 1 6cm 0 5cm qi mouth 0 8cm outlet (including top) first explore the interior of the glass double exports exports and export to the left above the three forms natural smoke was observed in different openings hot air occurs ceilinged building fires occur And in three outlet were blocked with qi and inlet port for natural smoke and hot air would affect the change and then with Schlieren optics to verify The results show that in the absence of blocking the air intake port and an unobstructed qi case since the left and above the outlet opening Jie accumulation and the underlying high-temperature air temperature However neither double exports accumulate underlying high-temperature air temperature is room temperature for personnel of the fire is relatively safe In the case of blocking the air intake port and an unobstructed qi quickly spread throughout the high-temperature flue gas of the internal model the bottom temperature goes up quickly Wherein the case of double outlet for faster more dangerous for personnel safet