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- Author or Editor: Orest Voznyak x
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Abstract
The article is devoted to decision of actual task of air distribution efficiency increase due to swirled air jets application. The aim of the paper is investigation of swirled air jets, analytical dependencies obtaining for determination of the air velocity attenuation coefficient, aerodynamic local resistance coefficient and noise level from the twisting plates inclination angle; optimization of the twisting plates inclination angle of the air distributor. It has been established that increase of the angle results in the air velocity attenuation coefficient increase and results in decrease of the noise level and resistance coefficient of air distributor. The optimum angle of the plates is determined considering aerodynamic, noise and energy aspects and equals 36°.
Abstract
The work is devoted to study of thermal efficiency of heating convectors with aluminum ribbing to ensure comfortable indoor conditions. The purpose of this paper is to evaluate theoretically and experimentally the thermal efficiency of convector-type heaters with aluminum ribbing, to implement numerical simulation and to obtain dependencies for determination of thermal characteristics of convector-type heaters with aluminum ribbing, ensuring of a proper both indoor climate in the premise and energy saving. A nomogram of interdependence between heat amount, heat carrying medium flow rate, the initial and final temperatures was created. Heat quantity increases with increasing heat carrying medium flow rate, the inlet temperature and decreases with increasing of the exit temperature.
Abstract
This article discusses the topical issue of improving the distribution of air in the premise due to application of the all type rectangular air streams: flat, axisymmetric and rectangular ones. The purpose of the article is research of the all types rectangular air streams, analytical dependencies obtaining for determination of the air velocity attenuation coefficient, aerodynamic local resistance coefficient and noise level from the ratio of slit length to its height; optimization of the inflow slit side's ratio. It has been established that increase of the inflow slit sides ratio results in the air velocity attenuation coefficient decrease and results in increase of the noise level and resistance coefficient of the rectangular slit. The optimal ratio of the sides of a rectangular slit is determined by the combination of aerodynamics and energetics, as well as of the sound power level.
Abstract
In this work, the actual aspect of the creation of comfortable climatic conditions indoors due to the compressed swirl compact air streams at an alternating mode is considered. The purpose of this article is the mathematical modeling of the swirl compact air jet and getting of the analytical equations for calculation air distribution in a premise at the condition of dynamic indoor climate in compressed conditions of a premise for providing comfort people well-being. A mathematical model of air supply with the swirl compact air jets in the room has been developed. A combinatorial-logarithmic method for the graphs approximating the dependence of the relative transverse velocity of a swirl compact air jet and the correction coefficient for compression and swirling on the relative transverse coordinate has been developed.
Abstract
The air temperature in school buildings significantly affects the ability of students and teachers to focus on the educational process. Students usually begin to feel an increase the temperature in room. The purpose of this study is to find the limit of the temperature rise in the classroom when people no longer feel the temperature rise in the room. For this reason, several experimental measurements of indoor air parameters were carried out: air temperature, relative humidity and carbon dioxide concentration. Measured temperature differences and individual subjective ratings of audiences determined the dependence using mathematical statistics, from which can be determined the critical level of increase in air temperature at which people no longer perceive the change in air temperature.
Abstract
The article is devoted to solving of urgent problem: creation of staff work safety in the boiler room due to ensure of required conditions by natural ventilation. The aim of the work is to eliminate the main damage of the natural ventilation system of the boiler premise by using of compact air jet due to correction coefficients and updated results. Static and dynamic air pressure, difference of static pressure due to wind, aerodynamic coefficients and air balance for necessary nature ventilation of the boiler premise as well temperature correction coefficient are established. The update calculation dependencies for determining of the air static pressure and its volume flow rate in the boiler room have been obtained. Updated graph, monogram, and analytical equations for natural ventilation calculation of boiler room are presented.
Abstract
The article is devoted to research of properties of the round convective air jet. The aim of this work is to establish universal graphical dependencies and empirical formulas for describing velocity and temperature fields over the entire range of development of round convective exhaust ventilation jet; development of an algorithm for solving the transcendent problem of determining the surface temperature of a heat source; introduction of velocity and temperature attenuation coefficients for round convective jet; visualization of its characteristics in the form of a 3D image; achieving reduction of metal consumption of the local exhaust ventilation system due to the overall optimization of the velocity and temperature fields of the round convective air jet.
