2021 ГОД
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Название статьи |
Авторы |
Год |
Название журнала |
Краткая аннотация |
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1 |
Computer technologies of 3d modeling by combustion processes to create effective methods of burning solid fuel and reduce harmful dust and gas emissions into the atmosphere |
Askarova, A., Bolegenova, S., Maximov, V., Bolegenova S., Askarov, N., Nugymanova, A. |
2021 |
Energies |
Using numerical methods, studies have been carried out to determine the effect of the introduction of the technology of two-stage combustion of high-ash Karaganda coal on the main characteristics of heat and mass transfer processes in the furnace of the BKZ-75 boiler at Shakhtinskaya TPP (Kazakhstan). Various regimes of supplying additional air into the combustion space, the volume of which varied from 0% (traditional basic version) to 30% of the total volume of air required for fuel combustion, have been investigated using 3D computer modeling methods. The performed computational experiments made it possible to obtain the distributions of the total velocity vector, temperature fields, concentration fields of carbon monoxide CO and nitrogen dioxide NO2 over the entire volume of the furnace and at the outlet from it. The introduction of the two-stage combustion technology made it possible to optimize the combustion of high-ash coal, since in this case there is an increase in the temperature in the torch core and a decrease in it at the outlet from the furnace, which has a significant effect on the chemical processes of the formation of combustion products. Based on the results obtained, it can be concluded that an increase in the percentage of air supplied through additional injectors to 18% leads to a decrease in the concentrations of carbon monoxide CO by about 36%, and nitrogen dioxide NO2 by 25% compared to the base case. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the furnace of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions into the atmosphere, and introduce a two-stage combustion technology at other coal-fired TPPs. |
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2 |
Numerical method to predict ice accretion shapes and performance penalties for rotating vertical axis wind turbines under icing conditions |
Baizhuma, Z., Kim, T., Son, C. |
2021 |
Journal of Wind Engineering and Industrial Aerodynamics https://doi.org/10.1016/j.jweia.2021.104708 |
This paper proposes a numerical method to predict the ice accretion shapes and aerodynamic performance of rotating vertical axis wind turbine (VAWTs) under icing conditions. A multiple reference frame (MRF) and sliding mesh technique (SMT) are combined to efficiently reflect the unsteady icing effects on rotating wind turbines. The SMT calculates the flow field considering the rotational and unsteady effects of the VAWTs. The MRF can efficiently clarify the rotational effects of the droplet field and ice accretion. Using the MRF technique, a series of icing simulations is implemented in which the ice shapes are updated at azimuth angle intervals of 36°. Using the proposed method, ice shapes in agreement with those obtained in icing wind tunnel tests can be obtained. Moreover, ice that is evenly distributed over the blade surface under glaze ice conditions can be examined instead of only the forms concentrated on the leading-edge, such as ice horns. The overall output power of an ice-covered VAWT is noted to be significantly reduced. Massive flow separation is induced owing to the increased airfoil thickness at azimuthal angles between 0° and 180°. Nevertheless, the performance of the thickened airfoil is enhanced owing to the delayed flow separation via dynamic stall in azimuthal angles between 180° and 270° |
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3 |
Numerical simulations on static Vertical Axis Wind Turbine blade icing |
Manatbayev, R., Baizhuma, Z., Bolegenova, S., Georgiev, A.
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2021 |
Renewable Energy https://doi.org/10.1016/j.renene.2021.02.023 |
During the last decade, there was an increased interest in wind turbine icing. Most of the icing studies are related to horizontal axis wind turbine icing (HAWT). Vertical axis wind turbine (VAWT) icing is seldomly reported in the literature. Compared to the HAWT blade VAWT blade operates under various angles of attack. Therefore, ice accretion shapes on static VAWT blade must be considered under different angles of attack. In the present study, a novel approach to predict ice accretion shapes on VAWT is described. Ice accretion shapes are obtained at a range of angles of attack between −25° and 25° using FENSAP-ICE which is the state-of-art icing simulation tool. Moving reference frame (MRF) was used to consider rotating effect on droplet field. The present method helped to draw the following conclusions. Firstly, the whole leading edge is covered by ice. Secondly, in rime ice conditions smooth ice shape is obtained, which does not significantly affect aerodynamic performance. Whereas in glaze ice conditions bumpy ice shapes causing massive flow separation and lift force degradation. Finally, iced VAWT loses up to 60% of power performance due to rime ice conditions. In glaze ice conditions VAWT is unable to produce power. |
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4 |
Parameters of heat treatment of coal to obtain combustible volatile substances |
Mergalimova, A., Ongar, B., Georgiev, A., Каlieva К., Abitaeva, R., Bissenbayev, P.
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2021 |
The article discusses the theoretical and practical foundations of the study of the possibility of obtaining volatile combustible substances released during special heat treatment of coal, with the aim of replacing ignition fuel oil at thermal power plants. The results of an experimental study of the coals of the Saryadyr field of three Kazakhstan deposits with the aim of obtaining volatile combustible substances, as well as the possibility of using these combustible substances as starting fuel, are presented. The results of calculating the heat of combustion of the gas obtained from the presented coal samples at different heating temperatures showed that with an increase in the heating temperature, the heat of combustion of combustible gases obtained from coal samples also increases. For all the coal samples under consideration, the maximum value of the heat of combustion is traced at a heating temperature of 600 °C. The greatest value is observed for the coal of the Shubarkul deposit - 22.1 MJ/m3, and the minimum value for the brown coal of the Saryadyr deposit is 13.5 MJ/m3. According to the results of experimental studies, we can conclude that of the three presented coals for producing combustible gas, the most suitable are the coals of the Shubarkul and Maikuben deposits. For use in the boiler unit as a starting fuel, it is sufficient to heat coal to temperatures of 350–450 °C. |