Influence of sunken squares on ventilation of underground comprehensive transportation hubs in hot summer and warm winter zone

The air conditioning operating conditions of the underground comprehensive transportation hub with the sunken square are simulated by CFD in hot summer and warm winter zone in winter and summer, and the distribution of the wind speed of the main cross-section of each floor and the wind in and out caused by the setting of the sunken square under typical winter and summer conditions are obtained and analysed based on the concepts of quasi-quiet wind area and air change rates. The results show that the wind entering and exiting the sunken square presents the characteristics of “one in and three out” under the summer condition and “two in and two out” under the winter condition. Due to the installation of the glass curtain wall, there is an obvious air flow path in the glass curtain wall. The ventilation performance of the building is affected by the change of outdoor wind direction, the setting of the sunken square, the opening area and the internal structure, and the outdoor air is easier to enter the indoor through the sunken square whose opening direction is the same as the wind direction, with large opening area and no large number of internal partition walls.