Abstract: Against the backdrop of national land planning and the strategy of building a country with strong transportation networks, the Transit-Oriented Development (TOD) model has become one of the key research approaches for the planning and construction of rail transit station areas in China. To address the issue of natural smoke exhaust failure caused by the thermal barrier effect in the large atriums of TOD complexes, this study takes an actual TOD complex as a prototype, establishes a numerical model of an 80 m high large atrium space, and constructs a 1∶15 scaled-down test bench for model validation. The study investigates the smoke spread patterns and smoke exhaust optimization strategies under the thermal barrier effect in the atrium space through numerical simulation and reduced-scale experiments. The results show that the temperature distribution in the large space is uneven, with a certain vertical temperature gradient (0.05~0.60 K/m). The thermal barrier effect prevents smoke from spreading to the ceiling, rendering the natural smoke exhaust vents at the top ineffective. Placing smoke exhaust outlets at the thermal barrier interface or adopting a dispersed multi-layer arrangement can effectively improve smoke exhaust efficiency, with the best performance achieved when outlets are arranged at the thermal barrier interface.

Key words: thermal barrier effect, crystal canyon, smoke spread, natural exhaust, numerical simulation