The aim of this work is to describe an approach to the formulation of surrogates of hydrocarbon fuels, taking into account the properties related to atomisation, heating, evaporation and combustion behaviours. These properties include the density, viscosity, lower calorific value, distillation curve, saturated vapour pressure, heat capacity, thermal conductivity, surface tension, molar ratio of hydrogen to carbon, molar mass, derived cetane number, and threshold soot index. Three diesel surrogates were developed using the proposed approach. Methods for calculating the physicochemical properties of both individual hydrocarbons and their mixtures are presented. The discrepancy between calculated results and experimental data for all properties is shown not to exceed 3%.Experimental studies were carried out in a lab-scaled combustion chamber, in which the properties of one of the three developed surrogates, DSSU3, were compared with those of diesel fuel. Also, the simulation results for DSSU3 were compared with published experimental data. It is shown that the properties of DSSU3 are a good match for those of diesel fuel. In addition, a kerosene surrogate was formed using the proposed approach. This allowed us to conclude that this approach to determining the properties of multi-component fuels is suitable for the formulation of both kerosene and diesel fuel surrogates.

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Hydrogen plays a key role in the transition to a carbon-free economy. Substitution of hydrocarbon fuel with hydrogen in gas turbine engines and power plants is an area of growing interest. This review discusses the combustion features of adding hydrogen as well as its influence on the characteristics of gas turbine combustion chambers as compared with methane. The paper presents the studies into pure hydrogen or methane and methane–hydrogen mixtures with various hydrogen contents. Hydrogen combustion shows a smaller ignition delay time and higher laminar flame speed with a shift in its maximum value to a rich mixture, which has a significant effect on the flashback inside the burner premixer, especially at elevated air temperatures. Another feature is an increased temperature of the flame, which can lead to an increased rate of nitrogen oxide formation. However, wider combustion concentration ranges contribute to the stable combustion of hydrogen at temperatures lower than those of methane. Along with this, it has been shown that even at the same adiabatic temperature, more nitrogen oxides are formed in a hydrogen flame than in a methane flame, which indicates another mechanism for NOx formation in addition to the Zeldovich mechanism. The article also summarizes some of the results of the studies into the effects of hydrogen on thermoacoustic instability, which depends on the inherent nature of pulsations during methane combustion. The presented data will be useful both to engineers who are engaged in solving the problems of designing hydrogen combustion devices and to scientists in this field of study.

The paper presents the results of studying the flow characteristics of liquid fuel in pressure jet atomizers of small-sized gas turbine engines with nozzle diameters of 0.4-0.6 mm for various operating and design parameters. The study was carried out using experimental measurements, semi-empirical correlations and CFD (computational fluid dynamics) methods. The Euler approach, the volume- of- fluid (VOF) method, was used to model multiphase flows in CFD simulations. Good agreement was obtained between experimental and predicted data on the fuel coefficient and the primary spray cone angle at the nozzle outlet. Besides, the assessment of the applicability of semi-empirical techniques for the nozzle configurations under consideration is given. In the future, the flow characteristics in question (the nozzle flow rate, the fuel film thickness, and the primary spray cone angle) can be used to determine the mean diameter of the droplets (SMD) required to fully determine the boundary conditions of fuel injection when modeling combustion processes in combustion chambers of small-sized gas turbine engines.

Hydrogen plays a key role in the transition to a carbon-free economy. One of the areas of hydrogen use is the substitution of hydrocarbon fuel in gas turbine engines and power plants. This review article discusses the features of hydrogen combustion and their influence on the characteristics of combustion chambers in comparison with methane. The paper presents both the results of a study of pure hydrogen or methane and methane-hydrogen mixtures with different hydrogen content. Among the main features, it is worth noting a smaller ignition delay time and higher laminar flame speed with a shift in its maximum value to a rich mixture, which significantly affects on flashback inside burners premixer, especially at elevated air temperatures. Another feature is the increased temperature of the flame, which can lead to an increase in the rate of nitrogen oxides formation. However, wider combustion concentration ranges contribute to the stable combustion of hydrogen at temperatures lower than those of methane. Along with this, it was shown that even at the same adiabatic temperature, more nitrogen oxides are formed in a hydrogen flame than in a methane flame, which indicates an additional mechanism for NOx formation in addition to the Zeldovich mechanism. The article also summarizes some of the results of a study on the effect of hydrogen on the occurrence of thermoacoustic instability, which depends on the initial nature of pulsations during methane combustion. The presented data will be useful both to engineers who are engaged in solving the problems of designing hydrogen combustion devices, and to scientists in this field of study.