EXPERIMENTAL INVESTIGATION OF SPRAYED EXTINGUISHING LIQUID DROPS MOVING FEATURES ON THE ENTERING INTO THE FLAME

The diagram, technique and results of series experiments to investigation of processes on the entering of typical extinguishing liquid — water drops into the flame are proposed. Modern high-speed measuring equipment operating on the basis of the method digital “tracer” visualization PIV (Particle Image Velocimetry) is used for the recording and processing of video frames in experiments. It is established that the measurement errors of liquid droplet sizes are no more than 0.001 mm, speed of the combustion products and water drops — 2 %. Video frames and the velocities fields, illustrating the entering of spray liquid flow (water with a “tracer” particles of titanium dioxide nanopowder) on the high-temperature combustion products are presented. Typical processes of turning the liquid droplets and the formation of vortex structures are analyzed. Significant effect of the velocity rising combustion products and sizes of water droplets on the degree of ash from the combustion zone is established. Depending for water drops velocities on the combustion products rates for different sizes drops are showed. Critical velocities of the combustion products in which they are entrainment of water droplets with different sizes are determined. The phenomenon of coagulation (merge) drops inherent in the process under investigation is analyzed. Two mechanisms for the origin and occurrence of this phenomenon are identified. The corresponding video frames are presented. The practical guidance on the parameters of liquid spraying (water drops sizes), which provide the entry of latest into the flames and the complete evaporation of the motion in the combustion zone for the conditions are formulated.