Zhodnocení tepelné bilance prostoru při aplikaci vysokotlaké vodní mlhy

Abstract

Water mist is used in a wide range of industries. Used in heavy, chemical or food industry. It finds its applicability through a wide range of mechanisms. Primary mechanisms include endothermic cooling, oxygen displacement and radiant heat shielding. The efficiency of water mist depends on their parameters and the parameters of the mist nozzle. These parameters include spray angle, droplet size, working pressure, spray speed, mist flux or water mist temperature. This dissertation examines the effect of droplet size and water mist temperature on the degree of endothermic cooling capability. Specifically, a measure of ambient cooling capability. The dissertation contains a theoretical and practical part. Theoretical part describes water and its properties. Other chapters are dedicated to water mist. Defining water mist and describing water mist history. Its practical use in fire protection, but also in other fields. Water mist mechanisms and mist nozzle parameters. The theoretical part is completed with methods to determine the particle size distribution. The practical part describes the complete apparatus that was used across the water mist measurements. The next chapter is dedicated to measurements made to determine the particle size distribution of individual nozzles. Based on the measurements, suitable nozzles were selected according to droplet size. The last chapter is dedicated to the firefighting of kerosene, technical gasoline and lamp oil and the subsequent ambient cooling. Nozzles marked SKA19, B1 and B3 were selected for the measurements. All measurements took place in a test room that was constructed for the purpose of measurement. The dimensions of the test room were intended to simulate confined spaces. The time required to extinguish, and the temperature course were monitored using thermocouples. The temperature course was evaluated in terms of the time required from the smallest maximum of all maxima in all measurements with a given fuel to reach a temperature of 35 °C. The resulting times were evaluated in terms of the effect of the water source temperature and the droplet size produced by each nozzle.