Increasing fire safety and fire extinguishing efficiency of an aerosol generator with a modified design

Purpose. Improving fire safety during operation of a fire-extinguishing aerosol generator (FEAG), which consists of reducing the temperature of the output flow of fire-extinguishing aerosol (FEA) to values that eliminate spontaneous combustion and melting of substances and materials in the protected area, achieved by a structural method of gas-dynamic cooling. Methods. Literature analysis; comparison of existing results of experimental and theoretical studies on reducing the outlet temperature of the fire extinguishing mixture flow of aerosol generators; comparison of an experimental sample and a serially produced generator during laboratory studies of the temperature fields of the aerosol flow and generator housings and during fire tests. Findings. A new design method for gas-dynamic cooling of a fire-extinguishing aerosol at the outlet of a FEAG has been developed. This method consists of modifying its design with a profiling insert, made according to the type of an annular Laval nozzle with a cylindrical central body, and ensures effective extinguishing of model fires. Based on a serially produced generator, an experimental model of the FEAG, modified with the specified design gas-dynamic cooler, was manufactured, fire tests of which confirmed a decrease in the temperature of the FEA flow at the exit from the generator by 70–75 % in comparison with the serially produced generator. The time to extinguish a flame fire in a protected area during fire tests was reduced by 2 times. Application field of research. The FEAG, modified with a gas-dynamic cooler in the form of a profiling insert, made in the style of a Laval annular nozzle with a cylindrical central body, can be effectively used as an operational means of extinguishing non-smoldering substances and materials.