Návrh optimálních parametrů požárních hadic

Abstract

This diploma thesis deals with pressure losses in fire hoses. In addition to the usually described losses, it focuses on the pressure drops that arise on the curvature of hoses. In the first part of the thesis, he acquaints the reader with the issue of pressure losses, explaining all the context necessary for understanding the work, starting with water as a fire extinguishing agent, by physical laws, to the description of pressure losses. At the same time, it adds a chapter of fire pumps, which summarizes the necessary information regarding these devices, especially the working diagrams of individual pumps used primarily for firefighters. At the beginning of the second part, the acquired knowledge of the estimation of pressure losses in fire intervention, both in the Czech Republic and abroad, are summarized. On this basis, a simplified calculation for this issue is created. Subsequently, there is also a detailed method of calculating pressure losses. Theoretically, the pressure losses of friction, then the local are gradually calculated, and finally the pressure drops at the curvature of the hoses. The latter area is theoretically discussed in detail. It is explained how water flows in a pipe bending where slowing down, where overpressure or, conversely, vacuum. There are also methods of calculating loss coefficients for bends on pipes from different sectors. The results of the calculations by the acquired loss coefficients are compared to each other. For the needs of this work, measurements were designed to compare theoretically acquired values with real quantities. The results are compared and brought into graphs, including the intensity of their similarity and differences. On the basis of the theoretical knowledge acquired, its own loss coefficient was designed, which describes the development of pressure losses on the curvature of hoses in practice. With its help, a calculation was also made for hoses on which the measurement was not carried out. At the end of the thesis, the designs of optimal hose diameters for different types of interventions, including pumping water from flooded areas, are then mentioned.