Influence of Irregularities of Water Vapor Field in Surface Layer of the Atmosphere on the Results of Satellite Monitoring of Hydropower Structures in Region of Reservoirs

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Results are presented for the modeling of coordinate errors in the projected GNSS system of monitoring the Zagorsk GAES-2 that are caused by local atmospheric irregularities in the surface layer. It has been established that for mean meteorological conditions, these errors can reach 0.8 mm for elevation and 0.1 mm for horizontal position. It is noted that actual instantaneous irregularities exceed mean values by an order of magnitude and can thus cause larger errors in coordinates

Dynamics of large-scale ionospheric inhomogeneities caused by a powerful radio emission of the Sura facility from the data collected onto ground-based GNSS network

© 2017, Pleiades Publishing, Ltd.The measurements of variations in the total electron content of the Earth’s ionosphere along the GPS satellite signal propagation path are described. The signal parameters were measured at a network of receivers at three distant sites: Sura (Vasilsursk), Zelenodolsk, and Kazan. They are arranged along the geomagnetic latitude of the Sura Facility under short-wave radio irradiation of the ionosphere. One feature of the experiment is the crossing of a disturbed region by the radio path between a GPS satellite and Vasilsursk. This resulted from the angular sizes of the Sura array pattern; the radio paths between a GPS satellite and Zelenodolsk and a GPS satellite and Kazan did not cross. Variations in the total electron content of up to 0.15−0.3 TECU were revealed at all three sites during four experimental campaigns (March 2010, March 2013, May 2013, and November 2013). The lateral scale of an ionospheric disturbance stimulated by a high-power radio wave and the velocity of its west-to-east propagation along the geomagnetic latitude were 30–60 km and 270–350 m/s, respectively. A decrease in the total electron content (down to 0.55 TECU) was recorded along the Kazan–Zelenodolsk–Vasilsurks line, which is connected with the solar terminator transit; the lateral scale of the related ionospheric inhomogeneities was ~65–80 km

The measurement of the ionospheric total content variations caused by a powerful radio emission of "sura" facility on a network of GNSS-receivers

© 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.Observations of the perturbations of total electron content (TEC) caused by a powerful radio emission of "Sura" facility (Radio Physical Research Institute, N. Novgorod) were carried out during several experimental campaigns from March of 2010 to March 2013. In this paper the data of experimental measurements of TEC-variations conducted on March, 15, 2010 and on March, 12, 2013, are presented. Parameters of TEC-variations were obtained by dual-frequency global navigation satellite systems (GNSS) diagnostics. Registration of signal parameters from GNSS-transmitters was performed at spatially separated sites along the geomagnetic latitude: Vasilsursk (56°08′N, 46°05′ E), Zelenodolsk (55°52′N, 48°33′E) and Kazan (55°48′N, 49°08′E). In the experiments radio path from GNSS satellite to Vasilsursk passed over the disturbed region of ionosphere, but radio paths to Zelenodolsk and to Kazan did not. However, TEC-variations correlated with pumping of ionosphere by "Sura" facility were detected for all up to three ground measurements sites. Magnitudes of TEC-variations reached up to ∼0.6-0.7 TECU. The speculation that a sharp gradient of the electron density formed at the border of the main lobe of "Sura" facility may cause the generation of IGW is presented

Estimation of Steam Turbine Shafts Fatigue Damage Caused by Torsional Vibrations

В Україні 74 енергоблоки потужністю 150-800 МВт теплових електростанцій із 102 перебувають на межі перевищення паркового ресурсу (220 тис. Годин). З них 17 енергоблоків наближаються до кінця ресурсу парку, а 11 енергоблоків досягли передбачуваного ресурсу (100 тис. Годин). Статистика аварій на електростанціях у різних країнах показує, що більшість з них спричинені тривалим накопиченням збитків від втоми. Серед основних причин пошкодження втоми - пульсація високотемпературних потоків пари в циліндрах турбіни, поперечні та крутильні коливання валів при тривалій експлуатації тощо. Це обумовлює розробку обчислювальних та експериментальних методів визначення втомних пошкоджень вали турбінних установок при динамічних навантаженнях. Оцінка втомних пошкоджень вала парової турбіни К-200-130 базується на 3D-моделі кінцевих елементів. Розрахунки враховують експериментально визначені втомні властивості роторної сталі. Розраховано втомну пошкодження в результаті крутильних коливань валу турбіни, спричинених аномальною роботою турбінного генератора. Зони концентрації напружень в обертових елементах парової турбіни типу К-200-130 встановлені для різних режимів роботи. Запропоновано процедуру прогнозування впливу втоми від пошкоджень на розрахунковий ресурс турбінного агрегату.In Ukraine, 74 power units with a capacity of 150-800 MW of thermal power plants out of 102 are on the verge of exceeding the park resource (220 thousand hours). Of these, 17 power units are close to the end the park resource, and 11 units have reached their estimated resource (100 thousand hours). Statistics of power plants accidents in different countries indicates that most of them are caused by the long term accumulation of fatigue damage. Among the main causes of fatigue damage are the pulsating of high-temperature steam flows in the turbine cylinders, transverse and torsional vibrations of shafts during long-term operation etc. This causes the development of computational and experimental methods for the determination of fatigue damage of turbine units’ shafts under dynamic loads. The evaluation of fatigue damage of steam turbine K-200-130 shaft is based on the 3D finite element model. The calculations take into account experimentally determined fatigue properties of rotor steel. The fatigue damage as a result of torsional vibrations of turbine shaft caused by the abnormal operation of turbine generator is calculated. Zones of stress concentration in the rotating elements of the steam turbine type K-200-130 are established for various operating modes. The procedure to predict the effect of fatigue damage on the estimated resource of turbine unit is proposed.В Украине 74 энергоблока мощностью 150-800 МВт тепловых электростанций из 102 находятся на грани превышения ресурса парка (220 тыс. Часов). Из них 17 энергоблоков близки к исчерпанию ресурса парка, а 11 энергоблоков вышли на расчетный ресурс (100 тыс. Часов). Статистика аварий на электростанциях в разных странах показывает, что большинство из них вызвано длительным накоплением усталостных повреждений. Среди основных причин усталостных повреждений - пульсации высокотемпературных потоков пара в цилиндрах турбины, поперечные и крутильные колебания валов при длительной эксплуатации и т. Д. Это вызывает развитие расчетных и экспериментальных методов определения усталостных повреждений. валы турбоагрегатов при динамических нагрузках. Оценка усталостных повреждений вала паровой турбины К-200-130 проводится на основе трехмерной конечно-элементной модели. В расчетах учтены экспериментально определенные усталостные свойства роторной стали. Рассчитано усталостное повреждение в результате крутильных колебаний вала турбины, вызванных ненормальной работой турбогенератора. Установлены зоны концентрации напряжений во вращающихся элементах паровой турбины типа К-200-130 для различных режимов работы. Предложена методика прогнозирования влияния усталостных повреждений на расчетный ресурс турбоагрегата

Influence of Irregularities of Water Vapor Field in Surface Layer of the Atmosphere on the Results of Satellite Monitoring of Hydropower Structures in Region of Reservoirs

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Results are presented for the modeling of coordinate errors in the projected GNSS system of monitoring the Zagorsk GAES-2 that are caused by local atmospheric irregularities in the surface layer. It has been established that for mean meteorological conditions, these errors can reach 0.8 mm for elevation and 0.1 mm for horizontal position. It is noted that actual instantaneous irregularities exceed mean values by an order of magnitude and can thus cause larger errors in coordinates

Application of the rescaled range analysis for vibro-acoustic imbalance control of rotary equipment

© Published under licence by IOP Publishing Ltd. The article discusses the possibility of using R/S analysis for vibro-acoustic unbalance control of rotary equipment. An algorithm for R/S analysis is presented. An application package and an information-measuring complex have been developed. Experimental studies on an axial ventilator are conducted. It has been established that in the absence of ventilator imbalance, the vibro-acoustic signal is close to random. With the advent of imbalance, the Hurst exponent changes

Control the tightness of the pipeline valve shutter according to the change in the Hurst exponent of vibroacoustic signals

The article is devoted to the study of the possibility of applying the method of standardized scope (R/S analysis) to control the tightness of the pipeline valve shutter. Experimental studies have confirmed the possibility of using R/S analysis to control the tightness of the pipeline valve shutter. Hurst’s exponent allows you to qualitatively determine the flow of the pipeline valve shutter

Application of the rescaled range analysis for vibro-acoustic imbalance control of rotary equipment

© Published under licence by IOP Publishing Ltd. The article discusses the possibility of using R/S analysis for vibro-acoustic unbalance control of rotary equipment. An algorithm for R/S analysis is presented. An application package and an information-measuring complex have been developed. Experimental studies on an axial ventilator are conducted. It has been established that in the absence of ventilator imbalance, the vibro-acoustic signal is close to random. With the advent of imbalance, the Hurst exponent changes

Classification of time series using the Hurst exponent

© Published under licence by IOP Publishing Ltd. The Hurst exponent allows to classify time series according to the level of their stochasticity. To calculate it, the rescaled range analysis (R/S analysis) is applied. The article presents the R/S analysis algorithm. A program has been developed in the LabView programming environment. Performance check program carried out on the model signals