SUPPRESSION OF THE FLAME OF COMBUSTIBLE LIQUIDS BY WATER SPRAY COOLING OF THEIR SURFACE

The problem of suppression of combustible liquids flame by cooling of a fuel surface layer up to the temperature when flame is extinguished is considered. The theoretical model is based on decision of the heat conductivity equation considering burn-out of liquid which surface is cooling by sprayed water in conditions of exponential initial distribution of temperature in a fuel layer. The boundary condition on a liquid surface is received from thermal streams balance on the interphase boundary. Due to the fact that the volume of thermal stream falling on a surface from flame is unknown, volume of this stream is found from the differential equation solution describing the stationary distribution of a temperature in a fuel layer. The assumption about approximate equality of a stream, conforming to stationary burning, to a heat stream on a flame extinction limit is used in calculations. The received boundary condition allows to close the equations system describing suppression of a flame and to solve the formulated task at exponential initial distribution of temperatures. The task is solved by an integrated thermal balance method allowing establishing dependence of a flame suppression time on intensity of supply of the sprayed water. The founded approximate solution contains only elementary functions and make obtained experimental data easy to interpret.