• Energy Research
• 2016-2025close
• natural sciences close
• social sciences close
• Russian close

Принятие комплекса законодательных актов в сфере энергетики, объединяемых термином Energiewende , существенно изменило структуру потребления энергии в Германии: в настоящее время наи-большую долю в ней занимает зеленая энергия, выработанная за счет использования ветра, солнца, воды и биомассы. Подобные изменения, безусловно, можно расценивать как успех. Однако, одновременно с целена-правленным изменением структуры производства и потребления энергии в Германии возникли определенные социально-политические, экономические и юридические проблемы, требующие тщательного изучения. Дискус-сионным является вопрос о соответствии целей и предлагаемых мер их достижения, в частности, в отношении бесперебойности энергообеспечения, расширения электрических сетей, совершенствования подхода к ценооб-разованию, экологических последствий с учетом курса на тотальное расширение производства энергии за счет возобновляемых источников. Актуальными для Германии и затрагивающими энергетическую политику России являются вопросы ускоренного сворачивания ядерной энергетики и легитимности национального курса Герма-нии на продвижение зеленой энергетики в контексте интеграции с Европейским энергетическим рынком. В статье выполнен анализ указанного комплекса проблем и охарактеризована роль национального законода-тельства Германии в их решении. from wind, solar, water and biomass now provides the largest contribution to the total electricity consumption. In this respect, Energiewende can be regarded as an overall success. But in parallel to this scenario, a critical discourse has evolved concerning socio-political, economic and legal issues. The congruence of objectives and measures for example, in regards to ensuring security of supply, expansion of electricity networks, development of electricity price and envi-ronmental consequences in the course of expansion of electricity generation from renewable sources is the main focus of socio-political and economic discussions. Accelerated phase-out of nuclear energy and constitutional disputes regarding the legality of national orientation of the promotional scheme for green electricity in respect to the integration of German electricity sector in the European internal market for energy are in the centre of the debate and have a remarkable impact on the energy policy in Russia as well. Against this background, present article examines the con-tribution of German Energiewende to the resolution of complex challenges of the developed industrial society. №4 (226) (2017)

This research aim is to develop a method for modeling the conditions for the critical hydraulic impacts emergence on thermal and nuclear power plants’ pipeline systems pressure pumps departing from the general provisions of the heat and hydrodynamic instability theory. On the developed method basis, the conditions giving rise to the reliability-critical hydraulic impacts emergence on pumps for the thermal and nuclear power plants’ typical pipeline system have been determined. With the flow characteristic minimum allowable (critical) sensitivity, the flow velocity fluctuations amplitude reaches critical values at which the pumps working elements’ failure occurs. The critical hydraulic impacts emergence corresponds to the transition of the vibrational heat-hydrodynamic instability into an aperiodic one. As research revealed, a highly promising approach as to the preventing the critical hydraulic impacts related to the foreground use of pumps having the most sensitive consumption (at supply network) performance (while other technical characteristics corresponding to that parameter). The research novelty refers to the suggested method elaborated by the authors’ team, which, in contrast to traditional approaches, is efficient in determining the pump hydraulic impact occurrence conditions when the vibrational heat-hydrodynamic instability transition to the aperiodic instability.

The aim of this paper was the development of a positional system model for a vector control of a static loads’ stand using the electrical drive and the study of the effect of various types of speed controllers and their settings on the dynamics of the transient processes during the simulation of the regulation and disturbance actions. This goal was achieved by the development of a vector control system model using the stand electric drive with the PID-speed controller setting, which ensured minimal speed errors and restrictions in the dynamic loads during the regulating and disturbing action. The synthesis of the current control circuits of the stator and speed in the torque control channel was performed. It was shown that using the existing PI-regulators of speed and current and their settings, the speed dynamic error was found to be as high as 21% at a regulating action, whereas during the disturbing action it was 8%. The achievement of the above indicators of the regulation quality was possible in the presence of the intensity setter at the speed regulator input. In this case the dynamic speed error while operating under control increased substantially. The introduction of the speed PID controller made it possible to reduce dynamic errors, however, it gave no desired results with the standard configuration. Changing the controller’s proportional part parameters allowed us to minimize the dynamic speed error while operation, both under regulating or disturbing influences.

The work is devoted to the study of heat transfer in channels with a longitudinal pressure gradient. The aim of the work is to develop methods for increasing the heat transfer intensity in channels with a longitudinal pressure gradient. The goal was achieved by developing the original design of the surface intensifier, made in the form of a horseshoe-shaped dimples, as well as by conducting heat transfer studies in the channel with a longitudinal pressure gradient and dimples of various geometries and locations. It was found that a numerical solution using the k-epsilon turbulence model shows not sufficiently stable results, including the values of local heat transfer coefficients can exceed 2 ... 2.5 times their actual values for a single dimple. Moreover, the use of the k-w-sst turbulence model shows more stable results. The most significant results obtained in the work are as follows: it was revealed that the use of holes, their geometry and location have a significant effect on the heat transfer intensity in a channel with a longitudinal pressure gradient; the design of the original horseshoe-shaped dimples has been developed, the use of which allows to intensify heat transfer by 13 ... 47% depending on the Reynolds number when they are arranged in three rows in the corridor order compared to staggered hemispherical dimples; when comparing the efficiency of using the developed dimples with hemispherical holes installed in three rows in the corridor order, the heat transfer increased by 21 ... 51% when the Reynolds number changed from 3000 to 15000.

A significant number of domestic and industrial boilers are in operation in Ukraine. Nitrogen oxides are the most dangerous among all combustion products that pollute the atmosphere, therefore, one should take some measures for decreasing the formation of nitrogen oxides during combustion. The studies were carried out at the boilers of low power (100 kW) with a tubular radiator and an open end. The studies in the furnaces of industrial steam boilers having a tubular radiator with a closed end have not been done. The numerical study results of the gaseous fuel combustion processes in the furnace of a DE-10/14 steam water-tube boiler are presented. The fuel-air mixture is formed by premixing the 15% part of the air with a primary burner twist factor n=2.4 and a secondary burner twist factor n=1.6, and an air excess factor αв=10. As a result of the studies, the temperature and velocity distributions of gases in the combustion chamber, the density of heat flows on the screen tubular surfaces, and the concentrations of the combustion components were determined. Flue gas recirculation in the volume of 80-100% is provided, and the reversible movement of combustion products towards the combustion front provides a reduction in the concentration of nitrogen oxides up to 123-125 mg/m3 at the furnace outlet. Disadvantages are the following: the formation of stagnant zones near the end of the secondary radiator. The optimum diameter of the tubular radiator equals to two burners diameters and tubular radiator is located at a distance of one meter from the burner cutoff.

The natural phenomenon of a tornado, known for its destructive power, is an object of study of many scientists. The available part of the data of field observations of this natural phenomenon is systematized and collected in the so-called Fujita scale. In particular, it indicates the width of the fracture band for tornadoes of different intensity, and only the values of the maximum wind speed are given from the gas dynamic parameters. Bautin S.P. proposed and justified the scheme of occurrence and functioning of natural ascending swirling flows of the tornado and tropical cyclones. Based on both this scheme and the data of the Fujita scale, the external radii of air inflow in the near-bottom parts of tornadoes of various intensities are established and the gas dynamic parameters of these flows are calculated. It turned out that in the case of the lowest intensity from the Fujita scale, the kinetic energy of the rotational motion of the air is half of the entire kinetic energy of the flow in the bottom part. As tornado intensity increases, the kinetic energy of rotational motion becomes the more prominent part of the total kinetic energy of the flow. In this paper, given the Fujita value of the width of the destruction zone for all tornadoes along with the two external radii of air inflow into the bottom part of the tornado are established as rin1 and rin2. The first of these radii, namely rin1 , denotes the radius at which the kinetic energy of the rotational motion of the constructed stream is half of all the kinetic energy of this stream. The second one denoted as rin2, is the radius at which the kinetic energy of the entire stream becomes equal to the kinetic energy of the weakest destructive tornado. Knowing the values of these radii allows reliable predicting the origin of the tornado. В настоящей работе при заданном в таблице Фудзиты значении ширины полосы разрушений для всех торнадо установлены два внешних радиуса притока воздуха в придонную часть торнадо: in1 и rin2. Первый из этих радиусов in1 такой, что кинетическая энергия вращательного движения построенного потока составляет половину всей его кинетической энергии. При втором радиусе rin2 кинетическая энергия всего потока становится равной кинетической энергии самого слабого торнадо, при котором имеют место разрушения. Знание значений этих радиусов позволит более надежно прогнозировать возникновение торнадо. №5(23) (2018)

The purpose of this work is the theoretical substantiation and development of a practical method for calculating the exchange fund of electrical equipment of an industrial enterprise. The purpose is achieved through the use of separate methods of queuing theory if the flow of applications for repairs and restoration are the simplest. It is confirmed by the results of statistical studies. Therefore, for the mathematical description of the repair problem the authors use the scheme [Mm; Ms; n], which corresponds to the process of death and reproduction. As a criterion for optimizing the exchange fund of electrical equipment it is proposed to use the zero probability waiting for the replacement of a faulty electrical component with a working from the exchange fund. For the case of the simplest flow of applications for service, the authors suggest to use the Peck and Hazelwood tables, which significantly simplify the calculation of the exchange fund for known failure rates and electrical equipment recoveries. For practical use of the proposed method, the authors have developed convenient forms for presenting initial data for calculating the exchange fund, and it is proposed to present the results of calculations in the form of several options for the optimal number of electrical equipment in the exchange fund depending on the accepted level of zero expectation probability, the number of elements from the exchange fund and their recovery time. The proposed method will optimize the exchange fund of electrical equipment and reduce the cost of its formation.

The presence of higher current harmonics has a negative impact on the efficiency and reliability of the elements of network. Higher current harmonics can lead to significant increases of resistance, voltage drop and active losses in busbar, also to decreasing network power factor. Existing engineering techniques can’t provide a reliable calculation of the parameters of busbars at higher current harmonics influences. Therefore, the aim of the work is to develop a new approach of parameters determination and the voltage drop estimation in busbar at higher current harmonics influence. Mathematical model of electromagnetic processes in busbar, which takes into account their design features, non-linearity of magnetic and electrophysical properties, proximity effects, surface and external surface effects, was developed and proposed. This model will allow to determinate the components of active and reactive resistances of busbar, voltage drops for each eigenvalue of the amplitude and frequency of current harmonics. Based on field simulation results was obtained the functional dependence in bicubic polynomial form. For effective spectra and amplitudes of higher harmonics, at selecting the corresponding polynomial coefficients, it will allow to determinate the components and the resulting values of voltage drops for an individual busbar’s design without spending time on field simulation. Based on the proposed approach, a method will be developed for the busbar's parameters identification and voltage drop estimation. This will allow effectively define the network configuration, installed capacity of compensating devices, which will provide the reliability of electrical collectors with the declared technical data and etc.

In this paper, we consider the problems related to measuring and analyzing the characteristics of partial discharges which are the main instrument for oil-filled high-voltage electrical equipment diagnosing. The experiments on recording of partial discharges in transformer oil have been carried out in the “point-plane” electrode system at alternating current. The instantaneous voltage and the apparent charge have been measured depending on the root-mean-square voltage and the phase angle of partial discharges. This paper aimes at carrying out a statistical analysis of the obtained experimental results, in particular, the construction of a parametric probabilistic model of the dependence of the partial discharge inception voltage distribution on the value of the root-mean-square voltage. It differs from usual discharges which occur in liquid dielectric materials in case of sharp inhomogeneous electrode system. It has been suggested that discharges of a different type are the discharges in gas bubbles that occur when partial discharges in a liquid emerge. This assumption is confirmed by the fact that the number of such discharges increases with increasing the root-meansquare voltage value. It is the main novelty of this paper. This corresponds to the nature of the occurrence of such discharges. After rejecting the observations corresponding to discharges in gas bubbles, a parametric probabilistic model has been constructed. The model obtained makes it possible to determine the probability of partial discharge occurrence in a liquid at a given value of the instantaneous voltage depending on the root-mean-square voltage. 

In 2011-2012 The parity of the cost of energy of thermal power plants on fossil fuels and the cost of energy from wind farms and solar power stations had come. Since 2017, the capacities of introduced renewable energy sources in the world have exceeded the volumes of commissioned capacities of traditional energy. The transition from traditional energy technologies to renewable energy sources (RES), which are becoming more profitable from an economic point of view and can minimize the negative impact of energy on the environment, is being phased. This article gives a review of the prospects of application of the combined schemes using renewable energy sources to generate energy. The paper discusses the most important areas of energy development in our country.