Experimental studies on smoke movement in a model tunnel with longitudinal ventilation

Results from a series of fire tests carried out in a horizontal model tunnel (1:10) with longitudinal ventilation are presented. Pool fire with methanol as the fuel was used to simulate the fire source. Temperature and velocity distribution in the model tunnel were measured. The heat release rate, maximum gas temperature under the ceiling, back-layering length and critical velocity were investigated and compared with models proposed previously. Predicted maximum gas temperature under tunnel ceiling by Kurioka’s model agreed well with the experimental data with maximum discrepancy less than 20%. Dimensionless back-layering length was found decreased with the increase of the dimensionless ventilation velocity nearly linearly. Due to the difference between the experimental conditions and validating conditions of models proposed previously, diversities were found between the experimental results and predicted values base on Froude modeling. Maximum discrepancy on critical velocity might be about 40%. Models considering the effect of boundaries and heat loss of smoke more detailedly remain to be further developed.

► Results of fire experiments with a model tunnel are provided. ► Kurioka’s model agrees well with the experiments with discrepancy less than 20%. ► Variation of back-layering length versus ventilation velocity is obtained. ► Models for critical velocity are validated by the experimental data.