A Study on Thermal Environment and Fire Safety in Buildings with Large Space

室外风对具有大开口（如中庭和空腔空间）的大型建筑的热环境和早期火灾有很大的影响。本文通过缩尺模型实验和现场实尺实验，对这些建筑物的热环境和火灾早期进行了研究。此外，为了检验正态k-ε湍流火灾模型的有效性，对实验结果进行了数值分析。通过这些讨论，为建筑火灾问题的解决提供了有效的设计方法。结论如下。(1)采用缩尺律模型实验可以近似地预测大开口中庭火灾的早期阶段。(2)从模型试验中可以看出，火灾阶段的发展过程因区域大小、外围风向和风速的不同而发生强烈的变化。(3)从全尺寸试验结果来看，空腔底部开口面积的大小对空腔内的热量和烟气运动有较大的影响。（4）由于Boussinesq近似模型计算结果高估了空腔内的高浮力流动，因此采用标准高雷诺数k-k-ε模型计算空腔内的气流和温度局部高于试验结果。但总的来说，当热源与周围空气之间的对流换热量一定时，计算结果的趋势和平均值与实验结果基本一致。

The outer-wind influences strongly on a thermal environment and an early stage of fire in large buildings with large openings (ex.atrium and cavity space). This study investigates the thermal environment and the early stage of the fire in those buildings by some model experiments with scaling-law and full-scale field experiements. Additionally, in order to examine the validity of a normal k-epsilon turbulence fire model, these experimental results are analyzed by it numerically. From these discussions, it presents the valid design method to the problem of fire in buildings. Conclusions are as follows. (1) The model experiment with scaling law can be used to predict, in an approximate manner, the early stage of the fire in the atrium with large openings. (2) From the model experiments, the process of the stage of fire changes strongly according to the differences of the size of the area, the outer-wind direction and velocity. (3) From the full-scale experiments, the size of opening area at bottom of cavity space has considerable effects on heat and smoke movements in it. (4) The computational air flow and temperature in the cavity space by using the standard high-Reynolds number k-epsilon model are locally higher than the experimental results, because the computational results by the model with Boussinesq approximation overestimate the highly-buoyancy flows. On the whole, however, the trends and averages of the calculated results generally correspond to the experiemental results when the proper amount of heat convection element from heat source to its surrounding air is known.