A formula of thermal drag was firstly established based on the revised concept,and then the relation between roundabout flow resistance,heat release rate(HRR) and airflow velocity was deduced.

• 首先在修正的热阻力概念基础上建立热阻力的表达式,然后推导绕流阻力与火灾规模和风速的关系式,最终建立比较严谨的火区阻力实用公式,并得到数值模拟的验证。