利用锥型量热计研究细水雾作用下的油池火热释放速率

热释放速率是燃烧过程最基本的特性参数之一，在研究细水雾与油池火相互作用时可以用来表示其动态发展过程．基于燃烧耗氧原理，锥型量热计被广泛利用来测量热释放速率，其测量条件之一是进入测量系统的气体仅来自于环境空气．当利用锥型量热计来研究细水雾与油池火相互作用时，部分细水雾会受热气化并改变进入锥型量热计中气体浓度，从而导致一定的热释放速率测量误差．本文提出了一种简单的方法来修正相应的热释放速率数据，并在此基础上利用锥型量热计研究了细水雾作用下的油池火热释放速率特性．实验中着重考虑了油池尺度、燃料特性、细水雾雾通量等因素的作用． 研究结果表明，在足够雾通量的细水雾作用下，热释放速率明显降低，然而在少量细水雾作用下，热释放速率会有所啬增加，对于一些不能完全燃烧的燃料试样，后者更加明显．

Heat Release Rate Study of a Pool Fire Interacted with Water Mists Using a Cone Calorimeter

Heat release rate is the most essential parameter for combustion process, and is often employed to study the dynamic suppression process of a pool fire under water mist application. Based on oxygen consumption theory, cone calorimeter is widely used to measure the heat release rate of a fire. However one of the main simplifying assumptions of this technique is that the incoming gases into the system only come from ambient atmosphere. When water mists are applied to the pool fire, some of them would be heated and evaporate into water vapor, so the incoming gas concentration would be affected, resulting in significant bias of the heat release rate measurement. In this paper a simple method to reduce this effect due to water vapor was developed and the heat release rate of the pool fire interacted with water mists was studied using the cone calorimeter. The factors such as pool scale, fuel type and water mist volume flux were considered in the experiments. The heat release rate was reduced significantly when water mists of adequate flux were applied to the pool fire, and however was enhanced with water mists of small quantity. As regards to some incomplete combustible fuel sample, the enhancement effect was obvious.