• Energy Research
• Closed Access close
• Restricted close
• engineering and technology close
• RU close

Technical solutions for optimizing the flame aerodynamics and the design of tangentially arranged burners in a TGMP-314 boiler are proposed. The implementation of these solutions will make it possible to achieve more reliable operation of the boiler during fuel oil combustion, smaller amount of NOx emissions during the combustion of gas and fuel oil, and a somewhat lower air excess factor in the furnace.

This paper analyzes the general issues of sectionalizing 110- and 220-kV distribution grids, including by current limiting. The results of calculations of transients in the event of various disturbances in the distribution network, taking into account the operation of emergency control devices, are presented. The results of comparative analysis of sectionalized and desectionalized distribution grids are presented. The authors hereof propose introducing a load increment safety factor to quantify how sectionalization or desectionalization could affect grid reliability. The paper further substantiates the need for accounting excess disturbances in sectionalized grids to design and implement measures to minimize accident-related losses. It analyzes the effectiveness of applying automatic load transfer (ALT) and draws recommendations on how to implement it.

The temperature dependence of the electrical conductivity of the molten eutectic GdCl3(0.515)–KCl(0.485) containing up to 3.3 mol % gadolinium oxide is studied. The temperature dependences of the conductivity of the molten GdCl3–KCl–Gd2O3 system are approximated by second-order polynomials. The formation of gadolinium oxychlorides is confirmed by spectral studies of the solidified melt.

Two approaches to synthesis of unsymmetrical disulfides based on different types of thiol activation, namely, an electrochemical method in the presence of a redox mediator and a microwave irradiation, were discussed. The mediated electrosynthesis procedures were carried out by the oxidative coupling of thiols or by the thiol-disulfide exchange in the presence of redox pairs—substituted o-aminophenol/o-iminobenzoquinone. It has been established that the formation of unsymmetrical disulfides under electrochemical conditions occurs as a result of both the oxidative coupling of sulfur-centered radicals, and a redox-mediator promoted thiol-disulfide exchange, which led to a high yield of heterodimeric products (89%–99%). The microwave-assisted synthesis made it possible to obtain the target products with yields of 13%–86% depending on different irradiation parameters such as power, temperature, and irradiation duration. However, this method requires a rigorous selection of conditions for each reaction and is therefore inferior to the electrochemical approach.

We have developed algorithms and programs for automated tests of synchronous machines. The programs were made using the LabVIEW development system. They are interrelated and have been combined into one software system. An approximation of its characteristics using regression equations of different orders with mean-square rate control is used in the algorithms to determine static parameters. A combined optimizing algorithm that is based on the least squares method and alternating-variable descent method is used to determine dynamic parameters. A new effective and adaptive method of sliding trigonometric interpolation is used to filter out possible noise in measuring channels of voltage and current sensors, while determining the parameters of sinusoidal signals in the stationary modes and dots of envelope curves in the transient modes. To reduce the time needed to obtain static characteristics, the software has a special virtual instrument with a field current control loop with a PID controller that provides desired field forcing. The SMTest software system has been tested using HIL modeling and laboratory test stations. Analysis of test results shows that, even when the acquired signal has a 30% noise level, the calculation error in the determination of parameters does not exceed 6%. The software, when used in stationary or mobile test stations, allows automating the process of obtaining characteristics and determining the main static and dynamic parameters of midand high-power rotor synchronous machines.

This short report substantiates the advisability of developing a two-stage model for the emergence and development of a boiling crisis. One of the stages is the violation of the stability of the two-phase wall layer, and the other is the appearance and fusion of dry spots on the heating surface. The use of a two-stage (“temporary”) model makes it possible to combine both well-known approaches to crisis analysis—hydrodynamic and thermal—in a single logical system. In the first approach, the characteristics of the boiling crisis are characteristic of high pressures in a boiling liquid, while those in the second are for low pressures.

Abstract The problem of mass transfer during anodic dissolution of vertical wire tungsten electrode in the alkaline solution under the conditions of natural convection is solved numerically. The concentration dependences of ionic diffusion coefficients, solution density and viscosity are taken into account. The distributions of concentrations, current density and potential over the near-anode layer are determined. The dependence of limiting current on the concentration of alkaline solution is obtained. The role of ion migration in the tungsten dissolution is shown. The results are compared with the experimental data.

Abstract The problem of fine particle gas cleaning is especially actual at the present time. This is due to the need to capture the desired product and waste gases cleaning. In both cases, the equipment should provide maximum collection efficiency. Cleaning of gas from thermal power plant (TPP) fly ash is serious problem. Coal-fired thermal power plants provide 27% of the total world energy consumption. Conventional TPP produce more than 700,000 tonnes of fly ash per year. Annually fly ash production only in Russia, according to various estimates, is 27–35 million tons. Various apparatus are used to clean the gases from the fly ash. Required collection efficiency of purification units must to be 99.5–99.7% and higher. Wet scrubbers makes ash recycling more difficult. It requires ash separation from the slurry and drying. One solution of gas cleaning problem is a electrocyclone. It provides gas purification efficiency up to 99.9% at initial ash concentration equal 50 g/m 3 and higher. An electrocyclone allows to obtain a product in dry form. Re-entrainment is return of captured material to clean gas stream. Re-entrainment in the gas cleaning equipment is one of the negative effects. Re-entrainment reduces equipment efficiency at high gas velocities. The present study was carried out to determine the value of re-entrainment in the electrocyclone. The object of study was the electrocyclone of ‘pipe in pipe’ type. Aluminosilicate fly ash from thermal power plant (TPP) was the test material. Study was carried out in dry and wet modes. Re-entrainment was observed in dry operation mode. No re-entrainment was observed in wet operation mode. The value of re-entrainment was calculated. It decreases collection efficiency from 99.9% to 60%. Re-entrainment depends on aerosol velocity (range 14–27 m/s) and the aerosol concentration (range 2–30 g/m 3 ). It is shown, what re-entrainment can be eliminated by water irrigation of collecting electrodes.