Перегляд зібрання за групою - Теми
- the beginning of World War III 1
- the coke rest 1
- the concept of organizational and economic mechanism 1
- the dispatcher of the duty control service of emergency call centres, stress resistance formation, simulating extreme activity conditions 1
- the educational process 1
- The environmental safety 1
- the environmental safety 1
- the express system of control of development nodes 1
- the in- dustrial noo-revolution, true Prehistory 1
- The influence of climate change on the ecological condition of the Oskil river basin 1
- the influence of oxidizing agents 1
- The Material Losses Risk 1
- the Model of Short-term Energy Security 1
- the multicomponent systems, the thermodynamic analysis, the subsolidus structure 1
- the nonlinearity of volt-ampere characteristics 1
- the object of increased danger 1
- The object of this study is a class B fire, which is extinguished with sprayed water. The subject of the study is the characteristics of class B fires when they are extinguished with sprayed water. Diffusion burning of a flammable liquid is considered as such a fire, and its extinguishing is carried out by cooling the flame. Heat and oxygen balance equations are used to build a mathematical model describing the fire extinguishing process. The components of the heat balance equation are the power of heat during heat release due to the chemical reaction of liquid combustion and the power of heat dissipated to the environment. The second component takes into account heat removal due to radiation, convection, and evaporation. The component of removed heat due to evaporation takes into account the Sreznevsky constant. The mathematical model that describes the process of extinguishing a class B fire is built in the class of models belonging to differential equations with constant coefficients. Analytical expressions were obtained for these static and dynamic coefficients, which include thermophysical, kinematic, and geometric parameters of the flame and fire extinguishing agent. To determine these characteristics, the constructed mathematical fire model was transformed using the integral Laplace transform. The dynamic characteristics of the fire were obtained in the time domain – the transient function of the fire, and in the frequency domain – the amplitude-frequency and phase-frequency characteristics of the fire. It is shown that the parameters of these dynamic characteristics should be determined experimentally. Experimental methods for determining parameters of dynamic fire characteristics have been devised. The presence of dynamic characteristics of class B fire makes it possible to spread the proven methods of the theory of control systems to design effective fire extinguishing systems 1
- the perovskite structure 1
- The pollution of water bodies, from diffusion sources 1
- The premises of a special purpose, a system of life support facilities, air ion generator, ionized air 1