| Popis: |
The indicators in the quantitative method are investigated to evaluate smoke exhaust performance in tunnel fires, which provides a theoretical basis for the optimization of the smoke extraction system under the lateral centralized mode. The criterion is proposed for plug-holing, and the theoretical models of smoke exhaust efficiency are established to distinguish whether the plug-holing occurs or not. The relationship between efficiency, effectiveness, and efficacy is analyzed from the perspective of smoke and heat exhaust. Meanwhile, this evaluation method is applied to the optimization of exhaust volume through FDS numerical simulation. The results show that Ri is a vital basis for judging the movement form of smoke and the exhaust effect. The critical value of Ri is 1.09 when plug-holing occurs, resulting in a significant reduction in the efficiency of smoke exhaust. The greater the exhaust volume of the exhaust fan, the greater the Ri value, the higher the total smoke and heat exhaust efficiency, and the better the exhaust effectiveness of smoke inlets without plug-holing. Under longitudinal ventilation, the optimal exhaust volume is 180m3/s at 20MW and 360m3/s at 50MW. |
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