摘要
为了研究火灾下混凝土空心板温度场分布,基于流固耦合传热理论,采用流体动力学软件FLUENT,建立空心板混凝土和封闭空洞内空气耦合模型并进行计算.通过典型算例,对相同外形尺寸下混凝土实心板和空心板温度场的分布进行了比较;对空洞内空气的自然对流和内壁面间辐射换热进行了分析;同时考虑了内壁面取绝热边界条件的可行性.分析结果表明:延火1h内,空心板与实心板温度场分布相近,随后差异明显;空洞通过内部空气自然对流与壁面间辐射换热对空心板温度场分布产生影响,并随延火时间增长而愈加明显;内壁面取绝热边界条件会高估空心板空洞附近的温度.空气-混凝土耦合传热系统模型可以解决常规单独计算混凝土空心板传热无法确定其空洞内边界条件的问题.
To research temperature field in concrete hollow-slab exposed to fire, based on the fluidsolid coupling heat-transfer theory, a coupling model of hollow-slab concrete and air in an enclosure was built to calculate temperature field by computational fluid dynamics （CFD） software FLUENT. Through a typical case, a comparison was made between the temperature distribution of a concrete hollow-slab and a solid-slab with the same outline dimensions. The heat transfer of natural convection in the enclosure and the radiation between inner walls were analyzed. In addition, the feasibility of setting inner wall boundary conditions to the heat insulation was taken into account. The results indicate that the temperature distribution of the concrete hollow-slab is similar to that of the solid-slab within 1 h of being exposed to fire, but different later. The hollow influences the temperature field in the concrete hollow-slab through natural convection of the air and radiation between the walls. The influence becomes more obvious with the increase in exposure time to fire. The temperature near the hollow is overestimated when inner wall boundary conditions are set to heat insulation. The model of the airconcrete coupling heat-transfer system can help to solve the boundary problems that cannot be defined by the traditional single solid heat transfer method.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2009年第3期536-540,共5页
Journal of Southeast University：Natural Science Edition
基金
江苏省交通科学研究计划资助项目(04Y051)
关键词
桥梁工程
混凝土空心板
火灾高温
耦合传热
bridge engineering
concrete hollow-slab
fires and high temperature
coupling heattransfer
