The paper experimentally investigates the integral characteristics of the processes involved in the reduction of gas temperature by injecting the aerosol flow of water droplets into a counter flow of combustion products (period of steady low gas temperature, T g ', compared to the initial, T g , range of temperature decrease (ΔT g = T g -T g '), rate of temperature recovery, the geometric dimensions of the temperature traces and their lifetime). We use the following recording devices: fast-response thermocouples (heat inertia less than 0.1 second), a multi-channel recorder, a high speed video camera (up to 10 5 frames per second), as well as a cross-correlation hardware and software package (with optical methods for recording the front and trace of the aerosol). The temperature trace of an aerosol is defined as the area with the temperature T g ' lower than the initial T g by at least 10 K. We determine how the following group of factors affects the characteristics of temperature traces of water droplets: size (0.04-0.4 mm) and concentrations (3·10 -5 -11·10 -5 m 3 of droplet per m 3 of gas) of droplets in a pulse, the initial temperature of water (280-340 K), the duration of a pulse (1-5 seconds), the temperature (350-950 K) and velocities (0.5-5 m/s) of combustion products. The temperature in a trace of water droplets during their motion in a flame can be reduced due to rapid vaporization or heat exchange between the gases and water. The conditions are identified, under which the low temperature of gases in a trace of droplet aerosol can be preserved for a long time (20-30 seconds). Finally, we forecast the parameters of temperature traces under the conditions of actual fires with combustion product temperatures over 1000 K.

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Abstract. To develop fire fighting technologies, the temperatures of combustible products were measured after passing an aerosol droplet flow of water through the flames (with monitored temperatures). It was applied the aerosol flows with droplets of sizes less than 100 μm, 100-200 μm, and 200-300 μm. Investigations were conducted at a temperature of combustible products from 500 K to 900 K. Temperatures of gases in droplet flow traces and maintaining times of relatively low temperatures in these areas (it can be considered as temperature trace) were defined. It was obtained the satisfactory agreement of experimental results and numerical simulation data.

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