An efficient and robust real-time longitudinal ventilation control method for unpredictable tunnel fire scenarios

A novel real-time control method, named SF-B control method, was proposed and a comprehensive numerical simulation study was conducted for feasibility analysis. The simulation utilized a combination of Python scripts and FDS. The SF-B control method incorporates automatic detection and localization of the fire source, and the existing ventilation velocity is corrected based on the real-time state of motion of smoke fronts and the backlayering length. The control logic of the SF-B control method was described in detail, and the criterion for determining stabilization was provided. After a comparison with PID control method, scenarios involving random constant HHRs, random fire locations and variable HRR were set up for separate simulations, and the results were compared with previous experimental findings. The outcomes demonstrate that the fluctuation of the SF-B control method is only about 1/10 of that of the PID control method, and the control performance is not significantly influenced by the HRR or fire location. It shows a more powerful control ability on smoke backlayering in scenarios involving variable HRR. This method exhibits excellent compatibility with different fire conditions, showcasing high ventilation control efficiency, robust control capabilities, and delivering reliable control results.