Experimental studies of mechanically exhausted smoke within the transport passage of the main transformer of an underground hydropower station

► Scale modeling experiments are conducted in a 1/12th underground transport passage. ► The results have been compared with full-scale experimental results. ► The results of the scale modeling experiments can be extrapolated to full scale. ► Spill plume has similar characteristics with smoke generated directly from fires. Scale modeling experiments were conducted in a 1/12th scale model of the underground transport passage of the main transformer of a hydropower station model. The influence of heat release rate and smoke exhaust rate on the smoke exhaust efficiency was investigated. Results showed that the smoke exhaust process was less efficient when the heat release rate was larger, and that better smoke control may be obtained with larger smoke exhaust rates. The results of the scale modeling experiments have been compared with full-scale experimental results in other studies. Through comparison, it can be concluded that the results of the scale modeling experiments may be extrapolated to full scale, and the spill plume has similar characteristics to the smoke generated directly from fires that had spread along the passage.