The Gas Interface Formation and Diffusion Characteristics Analysis in Ship Equipment Design

当中庭等大型封闭空间发生自发火灾时，需要能够安全疏散人员，因此排烟系统的完美设计就变得非常重要。如果空气对流中的热量和气体分布没有适当平衡，那么天花板下方自然会形成烟层，这可能会使烟雾散射现象变得复杂。本研究对火灾下中庭空间的烟雾界面形成和扩散特性进行了研究，以实现有效的烟雾控制。将剖面法应用到状态方程中，推导了烟层界面的形成条件，并得到了实验的证实。烟雾扩散分析考虑了各向异性湍流吹动以及动量、热量和烟雾传递方程中包含的浮力效应，并对某些烟雾特性做出了一些基本假设。通过对三层大型中庭的数值计算结果表明，在中庭顶部驱动排烟风机可以有效阻止烟雾扩散。结果总结如下：（1）可以看出，一般的分析方法可以用来预测封闭空间的烟雾扩散特性。（2）烟雾倾向于积聚在最高的甲板空间。（3）安装在顶部的排气扇对于清除烟雾非常有效。天花板。

In the event of spontaneous outbreak of fire in a large enclosed space such as an atrium, it is necessary that the personnel can be safely evacuated, whereby, the faultless design of the smoke management system becomes important. The natural tendency to form smoke layrs below the ceiling in the absence of properly balanced heat and gas distribution in the air convection, could make the phenomenon of smoke scattering complicated.This study makes an investigation of smoke interface formation and diffusion characteristics in an atrium-like space under fire for the purpose of effective smoke control. The formation condition of smoke layr interface is deduced by applying the profile method to the state equations, which was also confirmed experimentally. The analysis of smoke diffusino takes into account of an anisotropic turbulent blow with the buoyancy effects included in the momentum, heat and smoke transfer equations with a few basic assumptions made on some smoke properties. From the results of the numerical calculation in a three decked large atrium, it was clarified that by driving a smoke exhaust fan at the top of the atrium could effectively prevent the smoke diffusion.The results are summarized as follows.(1) It can be seen that the present analytecal method in general can be used to predict smoke diffusion characteristics in enclosed spaces.(2) Smoke tendds to accumulate the highest decked space.(3) It is very effective for purging smoke to operate the exhaust fan installed at top ceilling.