Research On The Relationship Between Ventilation And Smoke Patterns In Fire

Smoked patterns of wall is an important research content in fire investigation work, insome scene of the fire, because the ground traces and burning residue was damaged in theprocess of fighting and wall of smoky trace becomes especially important research value.Fire wall formation is the main reason of the fire smoked patterns the free carbon materialssuch as in the flue gas is adsorbed to the surface of a wall or cracks. Therefore, to researchmural face of smoky trace formation law of sandstrom, first to study the fire smokemovement. There are many factors that can influence of fire smoke movement, this papermainly explores the fire ventilation on fire smoked patterns the influence of the formationlaw of sandstrom, through the analysis of the theoretical model, physical model experimentand numerical simulation to study relevant laws.Based on the analysis on the basis of predecessors’ research results, firstly using thetheory of point source model, by using the parabola of v-shaped wall smoke mark tracecontour curve, determine the condition of no wind fire smoke plume and the surfaceposition relationship of the v-shaped smoky trace, and according to the results ofexperimental measurement, fitting out of the smoke plume of the cone busbar. On this basis,the model room set up three different layout of fire, through the experimental researchunder the conditions of natural smoke extraction and mechanical smoke extraction,variation rules of indoor fire wall Smoked patterns.Indoor fire layout as the center, fire wall under the condition of natural smokeextraction traces of the thinnest place should be in the fire. Ventilation reduces the thicknessof the wall at the top of the smoky trace, fire burning time shortened, and led to a smokytrace in the thinnest to the exhaust mouth direction apparent migration, influence theaccurate determination of the point of origin.Indoor fire wall fire for layout, ventilation has significantly reduced the thickness of thewall at the top of the smoky trace, fire burning time significantly shortened, but also tostrengthen the wall of v-shaped trace contour features: namely compared with traces ofnatural smoke extraction conditions, mechanical ventilation wall under the condition ofv-shaped trace contour are increased, the overall to the exhaust mouth slightly tilted,identify the fire more easily.Indoor fire corner fire for layout, the corner of the wall can form clear traces of V, iseasy to identify the fire. Because in front of the fire source is located in the model roomcorner, ventilation can only reduce the thickness of the wall at the top of the smoky trace,had a little effects on combustion flue gas temperature and time. Visible, if the fire sourcelocation close to fire or smoke the intake port and mechanical smoke exhaust effect onsurface trace is not big. Computer numerical simulation flue gas concentration distribution of thecharacterization of surface traces by calculation, the accuracy is higher. Compared withactual pictures of the Smoked patterns experiment, center and corner simulation result isvery close to the fire, fire wall of fire trace V can’t accurate to characterize withconcentration distribution, so the simulation accuracy is poorer. In general, the simulationexperimental results is reliable.