Scale modeling experiments of fire-induced smoke and extraction via mechanical ventilation in an underground hydropower plant

Abstract

This study explores experimental research that investigates the characteristics of fire-induced smoke and mechanical smoke extraction systems in the main powerhouse of the Ludila underground hydropower plant. Experiments adopting the similarity theory were conducted in a 1/12 scale model, which in turn was verified through empirical formulas. Experimental results reveal that the cooling effect was so striking that the maximum temperature in the occupied zone was 27.35 °C, and the egress time was over 18 min under conditions of fire intensity of 3 kW. Moreover, the influence of fire locations on CO concentration and smoke layer height are discussed in detail. Furthermore, the effects on temperature variations, the smoke ventilation system layout and exhaust rates caused by mechanical smoke extraction are analyzed. A turning point of smoke layer descent speed was discovered at 0.6 dimensionless height, and this study also recommends the optimal layout of smoke exhaust ventilators that should be used to reduce underground excavation loads. This will help to retrench the initial investment and thereby render a guideline in the design of sustainable underground engineering.