Research on temperature distribution and smoke movement characteristics of tunnel fires with a transverse fire source
Aims:This paper aims to study the effect of the flaming vehicle orientation on the temperature distribution and smoke movement characteristics of the tunnel ceiling.Methods:The maximum ceiling temperature rises and smoke back-layering rules of the two typical fire sources under different longitudinal velocity and fire source power were analyzed by numerical simulation combined with the scale model test.Results:Compared to the longitudinal fire source,the horizontal fire source had a stronger smoke blocking effect,with faster smoke movement near the ceiling and greater smoke roll absorption;and the fire source occupied a larger proportion of the tunnel width,with smoke spreading into the first dimension earlier,making the ceiling temperature lower.As the power of the fire source and the longitudinal velocity increased,the difference in ceiling temperature between the two fire sources increased,with a difference of up to 57% in the maximum ceiling temperature under a 30 MW fire source.Compared to the longitudinal fire source,the horizontal fire source tunnel ceiling temperature was lower.The smoke buoyancy was reduced;and the smoke movement was weakened.As the power of the fire source increased and the longitudinal velocity decreased,the difference in back-layering length gradually increased,with a maximum difference of 36 meters under a 30 MW fire source.Conclusions:The stability of the smoke layer of the horizontal fire source is weaker;and the smoke subsiding is more obvious.Even if the low velocity is small,the smoke layer near the fire source section can be destroyed.
safety engineeringtunnel firetransverse fire sourcetemperature distributionsmoke move-ment
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