高大厂房热压自然通风主导条件下排风扇局部降温特性

Effects of exhaust fan at buoyant-driven natural ventilation in workshop

以高大工业厂房为研究对象，建立了房间热压自然通风的物理模型和数学模型，对排风扇在厂房内减低局部温度的效果进行了分析．首先，通过比较热压通风房间理论模型与CFD方法的结果，验证了扩展区域热压通风计算的准确性和可靠性．其次，对于单侧墙壁安有排风扇和排风速度对降低厂房局部温度的作用进行了系统的分析．结果表明，由于结构上的涡流作用，局部排风扇的存在不仅没有降低设备密集区的温度，反而使得局部的热气无法排除，增加了局部的平均温度．在足够高的排风速度下，位于屋顶的通风口出现气流回流，加剧了局部温升．

This paper establishes a physical model and mathematical model of natural ventilation room. Effects of exhaust fan in reducing the local temperature equipment intensive areas are analyzed. By comparing the result of the computational fluid dynamics （CFD） to that of theoretical model, the CFD method is proved accurate and reliable in the calculating thermal driven natural ventilation. Two exhaust fans are installed at sidewall. Effects of exhausting velocity on reducing the local temperature of equipment intensive area are analyzed. The results show that the exhaust fan cannot reduce air temperature at equipment inten- sive zone as a circulation is formed at that area. The back flow at the roof ventilator exacerbated this tern perature rise when exhaust velocity is high enough.