Oleg V. Komarov’s research while affiliated with Ural Federal University and other places

Nowadays, energy demand continuously rises while energy stocks are dwindling. Using current resources more effectively is crucial for the world. A wide method to effectively utilize energy is to generate electricity using thermal gas turbines (GT). One of the most important problems that gas turbines suffer from is high ambient air temperature especially in summer. The current paper details the effects of ambient conditions on the performance of a gas turbine through energy audits taking into account the influence of ambient conditions on the specific heat capacity ( , isentropic exponent ( ) as well as the gas constant of air . A computer program was developed to examine the operation of a power plant at various ambient temperatures and relative humidities. The ambient temperatures ranged from 0 to 45 ºC, with relative humidities from 10 to 90%. The obtained results show that a GT operated at increased inlet air temperatures is characterized by lower net power and thermal efficiency. At higher inlet air temperatures, increased relative humidity has a slight positive impact on the GT cycle net power and its thermal efficiency. Net output power of the GT decreased from 93.3 MW at 15 °C to 70 MW at 45 °C. Its efficiency decreased from 32.32% at 5 °C to 28.3% at 30 °C. Although fuel consumption is reduced, the heat rate as well and the specific fuel consumption (SFC) are enhanced. SFC increased by 5.36% with a 10 °C temperature rise in temperature at a constant relative humidity. Therefore, use of a gas turbine with inlet air cooling and humidification is appropriate for improved GT efficiency.

Rationale. Gas turbine units are the most widespread type of power plants used in almost all industries. Such a wide distribution in combination with a high level of energy characteristics, high power density and maneuverability determine the relevance of research in the field of assessing their operating parameters. Goal of the work. The paper presents the results of an exergy analysis of a gas turbine plant as part of the Jandar Thermal Power Plant, Syria. The aim of the work was to determine the exergy characteristics (exergy efficiency and exergy destruction factor) of a gas turbine plant and to evaluate the efficiency of energy use in a gas turbine plant, as well as to analyze the effect of ambient temperature on the selected parameters. Materials and methods. To evaluate the described parameters, the method of exergy analysis of the thermodynamic characteristics of a gas turbine plant was used based on the first and second laws of thermodynamics in conjunction with the laws of conservation of mass and energy. An important feature of the study, which also emphasizes its novelty, is taking into account the chemical exergy of combustion gases during the exergy analysis. Results. Based on the results of the work, it was found that the maximum exergy efficiency was 92.8% and was typical for a turbine as part of a gas turbine, while the highest exergy destruction was observed for the process of fuel combustion in the combustion chamber and was equal to 80% (117.3 MW). The lowest exergy values corresponded to the compressor 6.0% (9 MW). For the gas turbine unit as a whole, the total exergy destruction was 147.3 MW, and the exergy efficiency was 53.3%. In this case, the main sources of irreversibility in the gas turbine unit are the combustion chamber and combustion gases. Conclusion. Exergy analysis is a convenient method for evaluating the thermodynamic perfection of gas turbine units. As a further line of work, it is necessary to more fully evaluate the effects of various conditions, such as air humidity or compressor pressure ratio, on the exergy characteristics of the gas turbine.

Исследована научно-техническая задача по моделированию газоабразивного изнашивания лопаточного аппарата осевого компрессора. Цели исследования — определение актуального состояния данного направления исследований и разработка методики расчета износа. Внимание направлено на верификацию расчетной методики на основании открытых результатов экспериментов с газоабразивной эрозией в поворотном канале трубы круглого сечения. Выполнен подробный обзор отечественной и зарубежной литературы. Исследование нацелено на прогнозирование величины эрозии лопаточного аппарата с помощью методов вычислительной газовой динамики. Представлено поэтапное описание алгоритма решения задачи численным методом с историческим обзором разработанных другими исследователями моделей эрозии. Проведена отработка алгоритма по расчету абразивной эрозии в осевом компрессоре и сделан анализ возможных алгоритмов расчета газодинамических характеристик компрессора, подвергшегося газоабразивному износу. Результаты исследования можно использовать при проектировании осевых компрессоров газотурбинных установок, работающих в условиях загрязненного воздуха. Таким образом, с помощью численного метода возможно проведение качественного и количественного анализа скорости газоабразивного износа проточной части осевого компрессора. Основной вклад в точность расчета величины эрозии вносит корректная калибровка модели эрозии, поэтому для получения адекватных результатов требуются достоверные экспериментальные данные по определению свойств взаимодействия эродирующих частиц со стенкой.

The study focuses on estimating thermodynamic characteristics at constant pressure for ambient air as a working fluid for gas turbines. The objective of this paper is to carry out a thermodynamic analysis of the properties of air as a working gas for a power plant. Various values of relative humidity, as well as temperatures, were examined in this study. Code was written using EES (Engineering Equations Solver) to conduct the simulation. This code contains the necessary equation to compute the thermodynamic characteristics of the working fluid. According to the results, both temperature and relative humidity remarkably influence the specific heat capacity (C_p), isentropic exponent (γ_h) as well as the gas constant of air (R_h). According to the results, when the ambient air temperature is increased from 0 to 45 ℃ with constant relative humidity values of either 10% or 90%, the specific heat capacity increases by 5.01% and 17.6%, respectively. Furthermore, the isentropic exponent decreases by 1.07% and 4.5%, respectively. The results show that the gas constant of air increases with ambient air temperature and relative humidity. One can conclude that the ambient conditions have considerable influence on the thermodynamic characteristics of a gas turbine working fluid.

In multistage axial compressors of gas turbine engines, there is a need for a detailed understanding of the flow field in between the blade rows, which could be obtained by spanwise traversing. This requires a pneumatic probe to be immersed into the flow path between the blade rows, where the space is limited. Therefore, the probe will affect the flow field around it and in the blade channel, and the probe readings will be affected by that flow field. As a result, these probe readings cannot be translated to flow parameters based on just the freestream calibration characteristics, obtained in the idealized wind tunnel. In our paper, we provide a computational analysis of the flow field around the cylindrical probe in a constrained inter-blade-row environment at different circumferential locations and flow conditions both upstream and downstream of the stator blade row. It is shown that the flow angle measurement error can reach up to five degrees in the mid-pitch locations compared to undistorted flow, and dynamic head measurements can be up to 30% away from the actual mean values of the flow. These deviations are shown to be caused by flow field interaction inside the blade channel and, as a result, measured values, obtained during industrial compressor testing, could be corrected accordingly. The universal correction procedure is proposed for further use in the industry

The main difficulty in assessing the technical condition of gas turbine units as part of gas-compressor units is the accurate calculation of the effective power. This paper presents an analysis of methods for determining the effective power of a gas turbine unit with a free power turbine to assess its technical condition. The main parameters of the gas turbine unit technical condition are considered. The division of parameters into local and integral is presented. The authors have developed a method for calculating the effective power of a gas turbine unit based on the parameters of a power turbine using gas-dynamic functions. This paper presents a comparison of the results in determining the gas turbine unit’s effective power according to the developed method, the torque meter, and the power consumed by a centrifugal natural gas compressor. The issues of tracking and predicting the degradation of the technical state of gas turbine units are discussed.

The paper presents a study of corner separations in hub to blade region at various operation conditions towards compressor stall. It is known that for compressor flows with low or none separations computation fluid dynamics with RANS methods work quite well, however, for highly separated flows they are no longer entirely valid. Therefore, several criteria were applied for prediction and quantification of possible corner separation, and the main interest of this work is in predicting the separation just before it will actually happen by certain flow metrics, so these metrics can be further used as a ‘pre-stall’ criteria whilst the RANS CFD operating point still behave within its appropriate limits. Also the effect of shear lean is discussed in the presented context.

In large pipeline gas transport systems the operation and maintenance of gas pumping units are carried according to the current number of equivalent working hours of centrifugal gas compressors and gas turbines. Modern terms of lean production require the maintenance procedure to be done according to the current technical performance of equipment. The paper presents a designed and verified methodology of technical performance estimation of gas turbine units using the standard measuring systems. This method includes a verified high-order mathematical model based on the gas dynamic function for the precise analytical description of turbomachinery aerodynamics. The models are defined for different types of multi-shaft gas turbines. In this article the results of technical performance estimation of different gas turbine units are discussed.