The production of cement clinker faces many management challenges, particularly in terms of consistently high product quality, efficient energy usage, and stable furnace operation. In this study, a machine learning model based on gradient boosting was developed for the efficient operation modes of the kiln (required quality and low energy consumption). The influence of process parameters on the efficiency of the clinker kiln was investigated. As a result, it was shown that stable kiln feeding improves the quality of the final product. High feeding variation leads to an increase in the dispersion of the entire setup and attempts to maintain it in a stable state by changing the volume of burned gas. When there is high feeder operation variation, the lime saturation factor has a significant impact on the outcome. The obtained results can be used to create a digital assistant for the kiln operator.

Nonlinear waves in a rectilinear rivulet flowing down a vertical plate are investigated on the basis of the developed semi-analytical model. The characteristics of nonlinear quasi-two-dimensional steady-state traveling waves are obtained numerically. Another wave family (the family of double-humped waves), branching off from the first family by doubling the spatial period, is found for small values of the wave number. It is shown that steady-state traveling waves do not exist in a certain narrow range of the excitation frequency, but a pulsating wave mode is realized.

The paper deals with the numerical study of aerodynamics and heat transfer for a case of a four-vortex furnace chamber designed for jet fire of brown coal from the Eastern-region coalfields. The combustion modeling is achieved by a set of linked submodels: they describe turbulent gas flow, thermal and radiative heat transfer, processes of degradation and burning for coal particles, and NOx generation. Simulation demonstrated that using of these types of brown coal in a specific-design furnace chamber creates a steady four-vortex flow structure that provides a uniform temperature field in the volume and admissible generation of NOx.

Nonlinear waves in a rectilinear rivulet flowing down a vertical plate are studied based on the developed theoretical model. The model equations are derived by the weighted residual method through projecting the Navier–Stokes equations onto the constructed system of basic orthogonal polynomials. Stability of the rivulet flow is analyzed and dispersion dependences for linear waves are obtained. Nonlinear wave regimes of a rivulet flow are numerically studied within the framework of two different problems, namely, the problem of stationary traveling waves with a given wavelength and the problem of spatial development of forced waves with a given frequency. Characteristics of nonlinear quasi-two-dimensional stationary traveling waves are obtained, and spatial development of forced waves is studied. Waves of various families are identified. It is shown that in a certain narrow range of excitation frequency, there are no stationary traveling waves, but a pulsating regime of flow occurs.

Four options for the power cycle using carbon dioxide as a working fluid during oxygen combustion of gaseous fuel are considered. In all the cases, heat is supplied within the zone of supercritical parameters of CO2. The fundamental difference in options lies in the method of increasing the working fluid pressure. The heat is supplied to the cycle in the combustion chamber, and the cycle operation is accompanied by continuous updating of the working fluid, since part of CO2 and all steam obtained during fuel combustion are removed from the cycle. It is shown that cycles with a single-stage pressure increase by a pump have the highest thermal efficiency, reaching 64.5 %. The effect of thermodynamic parameters on the energy characteristics of cycles has been estimated quantitatively.

In the present paper, the process of co-combustion of coal-water slurry (CWS) and pulverized coal fuel (PCF) in the E500 pilot-industrial boiler employing a stepwise arrangement of afterburning is investigated based on numerical simulation. To describe the CWS and PCF co-combustion, the authors used a model of the motion of a multicomponent non-isothermal gas medium (carrier phase) based on the RANS approach, a model of droplet/particle motion based on the Lagrange approach, and a model of combustion in the gas phase based on a hybrid model. The proposed comprehensive mathematical model was tested based on data from a full-scale experiment. For the first time, a detailed comparative analysis of the impact of changes in the design of a pilot-industrial boiler, using a three-stage arrangement of combustion and the flare-drip combustion technology for CWS on the physicochemical processes in the combustion chamber and environmental indicators was carried out. The change of circulation zones depending on the coal fuel supply method during the implementation of three-stage combustion was investigated. It has been revealed that using CWS as a reducing agent allows reducing the amount of harmful NOx emissions relative to the basic version by more than 40%.

The review considers problems of fluid dynamics and heat transfer in wavy liquid films under complex flow conditions. The term “complex conditions” here means the presence of fluxes of mass, momentum, and energy through the film surface. The purpose of the review is to analyze the latest achievements in investigations of wave modes of film flows.

The conditions of coal ignition and combustion with application of plasma ignition system have been studied experimentally. Research on plasma ignition of coal fuel flow was carried out on a pilot setup. The conditions were close to the industrial ones used for start-up of coal boilers. The operating range of the velocities of pulverized coal flow in the electric arc unit has been determined. It has been established that a stable process of ignition and further combustion of coal is possible at these flow velocities in the electric arc unit. The experimental setup was started up from a cold state and heated to a temperature of 1000°C; the start-up time did not exceed 200 s. Based on the obtained experimental results, an industrial prototype of plasma ignition system (PIS) was designed and tested with a TP-10 boiler with a capacity of 220 tons of steam per hour. The boiler was started up from a cold state by means of the PIS technology without use of fuel oil; the start-up time was 5 hours. After the pass of pulverized coal through the PIS, stable ignition and combustion of pulverized coal flame with a temperature of 1350°C was observed in the boiler. For the first time, a technology for ignition of pulverized coal boilers without use of fuel oil was created and implemented on the basis of a starting burner with plasma ignition of fuel. The technology features positive economic and environmental parameters in comparison with the widespread technology of starting up coal-fired boilers with liquid fuel combustion.

Abstract Adaptation of a mathematical model of gas diffusion combustion for different flow rates of CO–H 2 and a constant coal flow rate is carried out. It is shown that the results of calculating the main characteristics of the flame are in satisfactory agreement with experimental data and can be used to determine the structure of pulverized coal–gas flow, gas composition, particle and gas temperature, carbon combustion efficiency, etc. The proposed model is suitable for analyzing the stability of coal–gas flame and the transient processes accompanying changes in the mode of supply of the fuel-oxidizer medium.

Данная работа представляет результаты экспериментальных исследований и промышленного применения перспективных способов воспламенения и горения угольного топлива с использованием механохимической и плазменной активации. Экспериментальные исследования проводились на стенде тепловой мощностью до 5 МВт. Получены экспериментальные данные по реализации процесса горения и воспламенения с использованием технологий механоактивации и высоковольтного плазмотрона переменного тока. Проведено внедрение и первые промышленные испытания высоковольтного плазмотрона переменного тока на реальном энергетическом котле ТП-10 производительностью 220 т пара в час с замещением газа и мазута углем в процессе розжига котла.

The three-component Laser Doppler Anemometry method (3D-LDA) was used to study the internal aerodynamics of an experimental model of a promising furnace with a four-vortex scheme for burning coal fuel. Distributions of the averaged velocity and velocity fluctuations are obtained. There are no the pronounced peaks in the spectrum of velocity fluctuations, so we can speak about the stability of the investigated flow. The studied model is characterized by a high level of velocity fluctuations, provided for effective mixing of the pulverized coal mixture in the combustion chamber of the furnace.

The flow structure in a model of promising four-vortex furnace is investigated using three-dimensional laser Doppler anemometry method (3D-LDA). Using the “minimum total pressure” criterion, a vortex flow structure was visualized: the core looks like a deformed elliptical cylinder. Results has been compared with early PIV experiments and showed good agreement. The mathematical model for full-scale furnace numerical studies can be verified using these data.

В процессе обогащения углей образуются огромные объемы отходов, которые, как правило, выбрасываются в окружающее пространство, загрязняя его. При этом отходы могут содержать до 50% углерода. Малая промышленная энергетика, муниципальные котельные используют преимущественно слоевое сжигание углей. При этом коэффициент выгорания углерода составляет 50–60%, и коэффициент полезного действия котлов нередко не превышает 60%, а их экологические показатели не удовлетворяют современным требованиям. Эффективным способом решения проблемы утилизации углеотходов может оказаться перевод котлов на сжигание углей в виде водоугольной суспензии (ВУС). В статье представлены результаты авторов по технологии приготовления водоугольного топлива (ВУТ) и его сжиганию в вихревых топках котлов. Представлены данные по новому оборудованию, необходимому для реализации технологии. Показано, что и рядовые угли, и антрацит, и угольные шламы, а также отходы углеобогащения могут служить основой для производства ВУТ. Приведены примеры опытно-промышленного применения водоугольной технологии. При этом коэффициент выгорания топлива достигает значений порядка 95%, а коэффициент полезного действия котлов превышает 85%.

A swirling flow in a tangential-type hydrodynamic chamber with stationary vortex structures is experimentally investigated. The main attention is paid to determining the geometric and kinematic parameters necessary for a correct description of helical vortices and their spatial structure, in particular, to testing the possibility of a theoretical description of the limiting case where the vortex becomes stationary, i.e., its rotation frequency (or precession frequency) vanishes. It is shown that the theory of helical vortices ensures a sufficiently accurate prediction of conditions for the appearance of their stationary (motionless) states.

This paper presents an experimental study of diffusion jet combustion of gas at different flow rates of CH4–N2 and a constant flow rate of coal. Blow-off curves for a diffusion flame for different nozzle diameters are obtained. It is shown that an increase in the the nozzle diameter causes a decrease in the minimum residual flow rate of the fuel gas at which stable combustion is possible. As coal is supplied, the residual flow rate of the fuel gas also becomes slightly lower. The fluorescence of OH, which makes it possible to analyze the position and dynamics of the flame front is recorded.

The motion of a helical vortex and the movement of the fluid particles along its axis are analyzed. The same form of the helical axis of the vortex and the trajectory of the particles sometimes leads to a false assumption of equality of these two different motions. The correct identification of both motions, however, is essential when considering the helical vortices in the wakes of rotors, or the displacement of the core of helicoidal tornado, etc. Only the same helical shape is the vortex axis and the streamline of the fluid particles can mistakenly merge these two different motions as the identical travel. We describe an experiment that clearly separates these two motions for the case of a stationary helical vortex, along the axis of which the fluid particles intensively move. The result shows that the absolute velocity of fluid particles does not coincide with the motion of the helical vortex as a whole.

The Siberian Thermophysical Seminar (STS) has been traditionally held at Kutateladze Institute of Thermophysics SB RAS in Novosibirsk Akademgorodok since 1960. This area being thirty kilometers away for the city represents a largest scientific center in the easter part of Russia with 35 multidisciplinary institutes spread around Akademgorodok. List of Editorial Committee, Organizing Committee, Chairman, Deputy chairman, Scientific secretaries, Technical committee chairman, Members of the Organizing Committee and Scientific and advisory committees are available in this pdf.

A series of experimental investigations is performed for determining the thermal and environmental characteristics of burning heavy fuel oil of the M-100 type sprayed by a jet of superheated steam in a laboratory prototype of a new burner. A scheme of liquid fuel burning preventing choking of narrow fuel channels of injectors is proposed; this scheme ensures effective burning of high-viscosity fuels and wastes. The process of stable burning of heavy fuel oil in a low-power (7 kW) burner with low concentrations of toxic emissions and high combustion efficiency is realized.

Crude oil is an attractive fuel for energy production because it does not require the additional costs for processing and, in some cases, transportation. Existing technologies for combusting liquid fuel do not always ensure the achievement of required parameters, in particular, the environmental ones. The authors suggest to use the technology of crude oil burning in the presence of superheated steam as one of the ways to improve environmental performance at hydrocarbon combustion. For this purpose, the design of atmospheric burner with liquid fuel spraying by a jet of superheated steam was modernized. The regimes of crude oil combustion in a modernized burner are determined. The results obtained indicate the efficiency of using the proposed technology for combustion of crude oil sprayed by a jet of superheated steam, as well as the prospects of the developed design of a low-power burner for practical applications.

The internal aerodynamics of an isothermal laboratory model of a modified four-vortex furnace for a pulverized coal boiler have been experimentally studied. The digital tracer imaging (particle image velocimetry) technique was used to determine average flow velocity distributions and streamline projections in several sections of the model in various regimes of furnace operation determined by the velocity ratio of flows supplied via primary (main) and secondary nozzles. Conditions for the formation of a stable flow structure with four symmetric conjugated vortices in the entire volume of the furnace, as well as the domain of parameters leading to a nonregular spatial vortex structure, were determined.