During building fires, buoyant smoke is rapidly transported through elevator and ventilation shafts, posing a threat to the safety of occupants on higher floors. Therefore, smoke dynamics in vertical shafts are of interest to fire and building safety engineers. Herein, analytical solutions describing pure natural-convection laminar flows in asymmetrically-heated vertical shafts are introduced and discussed as a model situation. While the analytical solution is limited to laminar flow at relatively low Rayleigh numbers, a practically-relevant turbulent flow is explored experimentally, with a lab-scale 1-m-high shaft, and numerically, with Fire Dynamics Simulator (FDS) software in the same scale. With supplied heating powers of 100–400 W at the left-hand side wall or/and bottom, a circulatory 2D or/and 3D heat-induced convection flow (natural convection) sets in within the shaft. Air near the heated left wall rises due to buoyancy, while air near the cooler right wall descends, yielding a sine-wave-shaped velocity profile with no-slip boundary conditions imposed at both walls. While this sine-wave velocity profile is clearly observed in laminar flow, the buoyancy-driven layers are relatively thin in the corresponding turbulent flow. The temperature profile practically linearly decreases from the left to the right wall for both laminar and turbulent flows. The overall physical insights provided by the laminar analytical solution are consistent with observations in the turbulent flow. The differences between laminar and turbulent flows are investigated and discussed by qualitatively comparing the analytical solutions to the experimental and numerical data.

在建筑物发生火灾时，漂浮的烟雾会迅速通过电梯和通风井输送，对较高楼层居住者的安全构成威胁。因此，垂直竖井中的烟雾动力学是消防和建筑安全工程师感兴趣的。在此，介绍了描述非对称加热竖井中纯自然对流层流的解析解，并作为模型情况进行了讨论。虽然解析解仅限于瑞利数相对较低的层流，但实际相关的湍流是通过实验探索的，使用实验室规模的 1 米高轴，并在数值上使用 Fire Dynamics Simulator (FDS) 软件在相同的规模。在左侧壁或/和底部提供 100–400 W 的加热功率，循环 2D 或/和 3D 热诱导对流（自然对流）设置在轴内。加热的左壁附近的空气由于浮力而上升，而较冷的右壁附近的空气下降，产生正弦波形状的速度剖面，并在两壁上施加无滑移边界条件。虽然在层流中可以清楚地观察到这种正弦波速度分布，但在相应的湍流中浮力驱动层相对较薄。对于层流和湍流，温度曲线实际上从左壁到右壁线性降低。层流解析解提供的整体物理见解与湍流中的观察结果一致。