Experimental and Numerical Study on Fire Extinguishment Efficiency of Water Mist with Obstruction

The full scale tests and numerical simulations were carried out to investigate the validity of the obstacle fires extinguishment by water mist on the conditions of reticulation and strip obstacles.Shape,location,and shielding area of the obstacles and water pressure were considered as the main influencing factors on the extinguishment effect.The results show that increase of the pressure is helpful to improve the validity.Location of the obstacle is the crucial influencing factor.It is difficult to get into the flame for mist because of near coverage,and a partial high temperature zone occurs under the obstacle,so the remaining fire is hard to be put out.The extinguishment time is 56 s at least.With far coverage,water mist scatters equally over the flame relatively by entrainment.The cooling effect from mist is obvious;the extinguishment times are within 18s.There is little effect with different shielding area of the reticulation obstacles on the extinguishment.With the same shielding area,fires with strip obstacles are difficult to be extinguished.