Abstract This study proposed a hybrid ventilation mode for underground subway depot with superstructures and described the construction of a calculation model for estimating the smoke-exhaust efficiency of ventilation systems in such buildings. The hybrid ventilation system consisted of natural ventilation, a flow deflector, and mechanical fans. The smoke-layer height, smoke temperature, gas-flow routes, and velocity distribution under the ceiling were recorded, and the smoke-exhaust efficiencies of the three ventilation modes were calculated and compared. The results revealed a lower ceiling temperature in hybrid ventilation than in mechanical ventilation or natural ventilation systems, with no smoke accumulation in the bottom layer or interlayer. Therefore, the thickness and stability of the smoke layer was determined to be more desirable in hybrid ventilation than in the other two ventilation systems. Gas-flow routes demonstrated that air from outside flowed in through the side window along the ceiling of the bottom layer to the exhaust fan. The dispersion of hot smoke was thus impeded, and smoke was entrained into the fan. The smoke-exhaust efficiencies of hybrid ventilation and mechanical ventilation systems were similar, and both were higher than that of natural ventilation.

中文翻译：

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地铁地下车库上部结构混合通风数值模拟

摘要 本研究提出了一种带有上部结构的地下地铁段的混合通风模式，并描述了用于估算此类建筑物通风系统排烟效率的计算模型的构建。混合通风系统由自然通风、导流板和机械风扇组成。记录烟气层高度、烟气温度、气流路径和天花板下的速度分布，并计算和比较三种通风方式的排烟效率。结果表明，混合通风的天花板温度低于机械通风或自然通风系统，底层或夹层没有烟雾积聚。所以，烟气层的厚度和稳定性在混合通风中比在其他两个通风系统中更理想。气流路径表明，来自外部的空气通过侧窗沿底层天花板流入排气扇。热烟的扩散因此受到阻碍，并且烟被夹带入风扇中。混合通风和机械通风系统的排烟效率相似，均高于自然通风。