大空间建筑火灾中火焰辐射对无保护钢构件升温的影响

大空间建筑的空间尺度变化范围较大，当空间尺度变化时火焰对壁面或构件的热辐射变化也较大，正确预测火焰辐射对构件升温的影响，是准确计算火灾场景中构件升温的一个重要环节。在计算假定条件下，通过分析外界与构件之间的热量交换以及影响火焰辐射的因素，导出考虑火焰辐射影响的构件净吸热量计算公式，将构件净吸热量计算公式导入基于集总热容法的热平衡方程中，得到构件升温的数值解，从而定量确定火焰辐射对钢构件升温影响的，临界角系数，为简化钢构件升温计算奠定基础，使钢构件升温计算既准确反映火灾中构件的升温历程，又方便实用。

Fire Radiation Effect on Steel Member at Elevated Temperature in Large Space Fire

Large space build has wide ranges of space dimension. Heat radiation from fire to wall or member has great changes as space dimension variation. Estimating fire radiation correctly is very important for calculating temperature rise in steel structural elements. The formula of heat absorption net capacity including fire radiation can be derived from analyzing the influence factors of fire radiation and heat exchange between external environment and steel member. The numerical solution of elevated temperature of steel member can be derived from substituting the heat absorption net capacity equation into heat equilibrium equation which bases on the lumped differential formulation. Then the critical radiation shape factor of fire radiation affected on steel member can be determined. Simplified approach of temperature rise in steel member bases on the critical radiation shape factor and estimates the temperature rise in steel member accurately and convenience.