摘要
对于局部火灾,需要考虑建筑物构件在不均匀受热情况下的热学与力学响应。以方钢管梁为研究对象,模拟其不同高度处承受底部火羽流冲击作用的热力学现象。不同于应用绝热表面温度概念来实现流固传热的单向迭代耦合,提出一种新的计算流体力学-有限元数值(computational fluid dynamics-finite element method,CFD-FEM)模拟手段,通过采用CFD方法统一分析火灾模块与热模块来实现流固传热界面的双向直接耦合。首先通过典型局部火灾试验验证了该数值方法的准确性。继而在火灾模块中探究了空间速度场与温度场的分布规律,在热模块中探究了不同高度处钢梁壁面热流的变化规律,以及辐射与对流热流随时间的变化规律。最后以固体温度为边界条件完成了结构模块分析,实现了固体域热力耦合,探讨了在此局部火灾场景下不同高度处钢梁的力学响应,探讨了其在受热后出现的屈服强度退化现象。
For localized fire,it is necessary to consider the thermal and mechanical response of building elements under uneven heating.The object of this paper is a square steel tube beam,simulating its thermomechanical phenomena under the flame impact on its bottom at different heights.Instead of applying the concept of adiabatic surface temperature to realize the one-way iterative coupling of fluid-solid heat transfer,this paper proposes a new computational fluid dynamics-finite element method(CFD-FEM)simulation methodology to realize the two-way direct coupling of fluid-solid heat transfer.In this direct coupled form,the fire model and the thermal model are addressed together by CFD method.Firstly,the accuracy of the numerical method is verified by a typical local fire test.Then,the distribution of the velocity and temperature fields is investigated in the fire model.The variation of the surface heat flux of the steel beams at different heights and the variation of the radiative and convective heat flux with time are investigated in the thermal model.Following this,the structural model analysis is completed using the solid temperature as the boundary condition to achieve thermal-mechanical coupling in the solid domain.The mechanical response of steel beams at different heights in this local fire condition is discussed,and the degradation of yield strength after heating is found.
作者
周靖罡
王伟
周晅毅
丛北华
ZHOU Jinggang;WANG Wei;ZHOU Xuanyi;CONG Beihua(State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;Shanghai Institute of Disaster Prevention and Relief,Tongji University,Shanghai 200092,China)
出处
《建筑钢结构进展》
北大核心
2025年第3期38-45,共8页
Progress in Steel Building Structures
基金
国家自然科学基金(52078380、51820105013)
土木工程Ⅰ类高峰学科建设经费(2022-3-YB-18)。
关键词
计算流体力学
局部火灾
流固传热
钢梁
热力耦合
热流
computational fluid dynamics
localized fire
fluid-solid heat transfer
steel beam
thermal-mechanical coupling
heat flux
