Experimental Study On Temperature Characteristics In Closed Cabin

One of the most common scenarios of fire is the chamber fire which has been paid specially attention and studied by lots of researchers. So far, fires in buildings with outlets such as windows and doors have been studied and the corresponding fire models have been developed, but few researches have been found about the fire in closed chamber without outlets or with only roof outlet.This paper conducted a lab-scale experimental research using an enclosed cabin fire testing system developed by ourselves, aiming at to reveal the principles of the combustion and the smoke movement in fires occurred in enclosed cabin. The experiment was conducted in a closed ship cabin with the dimension of 1000mm(L)×1000mm(W)×750mm(H). The properties of the fire in a chamber without outlet was studied, emphasized at temperature distribution and the smoke movement in the cabin. Through analyzing the experimental data using various methods such as theoretical induction, analogy, non-dimension analysis etc., the characteristics of the temperature distribution and the smoke movement of fire in closed boat cabin were concluded as following:Fire in enclosed cabin usually consists three consequent periods, namely the developing period, the temperature steady increasing period and the close-burnout period. At the horizontal direction, most of spaces, the same temperature appears at the same height in the cabin; at the vertical direction, the gas in the cabin can be classified into two layers: the upper layer with high temperature and the lower layer with even gradient of distribution. In the upper area, the temperature remains the same everywhere and has nothing to do with the height, while in the lower area, the temperature is an one order function with the height, namely, is in direct proportion with the height.Considering that the temperature distribution in the cabin at the time of burnout can be represented as a separable function and the dimensionless temperature distribution is consist with the united Boltzmann equation, a model for predicting the temperature at the time of burnout has been proposed, which provides the theoretical basis for estimate an appropriate time to open the cabin after the fire suppression of a ship fireThe movement of the smoke in fires of enclosed cabin is very different from that in the normal buildings with vertical outlets. Here, the traditional two-zone model, in which the space is divided into the hot smoke layer and the cold gas layer, is not suitable anymore. Instead, as the time elapsed, the original three layers of smoke, which consists of the hot smoke layer, the cold smoke layer and the transitional layer, change into two layers, namely the hot smoke layer and the transitional layer, where the cold gas layer disappears. The height of the smoke interface in fires in enclosed cabin changes as the form of exponential attenuation with the time, a model has been proposed of the height of the smoke interface with different fire powers.