Influence Mechanism Study on Smoke Temperature Characteristics under Low-Pressure Tunnel Environment with Spatial Blockage Effects

This study focuses on the unique low-pressure environment of traffic tunnels in plateau regions, taking the scenario of severe damage caused by burning tanker trucks as the study starting point. By combining the Fluent simulation software with experimental data, the study thoroughly explores the impact of different traffic vehicle blockage effects on smoke diffusion and temperature field in tunnels during fires. The study emphasizes the blockage effects generated by traffic vehicles in both lateral and longitudinal spatial dimensions within the tunnel, aiming to investigate the temperature and smoke flow patterns in tunnel fires. The results indicate that the blockage ratio significantly affects smoke diffusion, whereas the influence of blockage length is relatively minor. At the characteristic height of the human eye on evacuation platforms, the impact of vehicle blockage effects is relatively limited, especially under the control of longitudinal mechanical ventilation airflow. Furthermore, both the blockage ratio and length have a significant impact on the maximum ceiling temperature. Based on the study of blockage ratio and length, a prediction model for the maximum ceiling temperature rise based on blockage ratio is proposed. This model fully considers the extreme fire burning and vehicle blockage effects in fire scenarios, providing strong data support for improving the level of fire safety and control in traffic tunnels.