Keywords: reciprocating engine, cylinder liner microarc oxidation, ceramic plating, thermal analysis, thermal conductivity coefficient.

Presented are method and results of investigation into the influence of thickness and thermal conductivity of ceramic plating, applied with microarc oxidation method, onto the thermal condition of the liner. The method of plated cylinder liner thermal analysis, making use of SolidWorks Simulation software package, is described. Temperature of cylinder liner surface under the plating was measured in three zones: the upper zone, the middle zone (contacting with the piston), and the lower zone. Each zone is characterized by zone-specific boundary conditions, as close as possible to real liner operating conditions. Furthermore, thermal condition of unplated cylinder liner has been analyzed. Also, dependence of cylinder liner temperature on plating thickness and thermal conductivity.

Keywords: axial turbine stage, computation hydraulic gas dynamics, Ansys CFX software package, nonstationary flow, aerodynamic interaction of blade rows, inter-row axial clearance, blade spacing ratio.

Periodical nonstationarity of flow in modern gas turbines leads to variability of aerodynamic forces exerted to the blades, which results in higher losses of flow kinetic energy. This work aims at elaboration of recommended ranges of nondimensional geometric parameters (based on numerical analysis of turbine stages’ aerodynamic characteristics), with a view to reduce nonstationary loads of the blades, so as to mitigate blade vibrations and minimize losses of kinetic energy, thus maximizing internal turbine efficiency. This work also examines the influence of inter-row axial clearance and blade spacing ratio, as applied to turbine stage LPI-1. er-row axial clearance and blade spacing ratio, as applied to turbine stage LPI-1.

Keywords: marine diesel engines, evaluation of engine operability, residual life, diagnostic methods, instrument inspection, mathematical apparatus.

The article discusses evaluation of marine engine operability based on its residual life, using various diagnostic methods. Demonstrated are advantages and drawbacks of each diagnostic method, using instrument inspection and results of combustion parameters registration. Diagnostic methods are evaluated from the viewpoint of their suitability for finding methods of engine residual life restoration, acceptable for implementation in nuclear power industry. As it was shown, there are no universal diagnostic method, which would guarantee exact estimation of marine engine operability and residual life.

Keywords: diesel engine, oil-based diesel fuel, vegetable oil, self-ignition, cetane number.

The authors offered a method of comparative analysis of vegetable oil combustibility in diesel engine combustion chamber. This method includes determination of factors affecting vegetable oil cetane number, and identifies the most important of said factors. Vegetable oil cetane number is shown as depending on its ignition point in closed crucible, oleic acid and saturated fatty acid percentage. Correlation analysis of the above dependencies has been carried out. The dependency of vegetable oil cetane number on its ignition point in closed crucible is shown as providing maximum correlation density.

Keywords: diesel fuel, ethanol-containing emulsion, molybdenum dioxide, stabilization, cetane number, ignition lag, combustion temperature.

The authors investigated performance of ethanol-containing emulsion, containing a complex-action additive. The aim of the work is examination of molybdenum disulphide performance as a corrective additive to fuel. The authors provide theoretical justification of additive selection, description of molybdenum disulphide-based additive action mechanism on stabilization and kinetics of high-concentration combustion. The investigation includes theoretical analysis and experimental validation of results.

Keywords: diesel engine, cold start, warm-up, wear, cylinder liner, piston, lubrication, combustion incompleteness, fuel activation, combustible mixture temperature.

According to the results of our analysis and experiments, during the warm-up period 10 to 15% fuel injected into the combustion chamber is burned there, while the rest fuel is exhausted to the environment in the form of steam and condensate. The investigation is targeted at optimization of warm-up characteristics after the cold start. It is shown that during 6 minutes-long warm-up period unburned fuel percentage drops down from 60-70% to 10%. Then, energy flow characteristics are gradually stabilizing during the post-start period. According to the results of our experiments, energy losses may be considerably reduced by means of fuel activation upstream of the injectors, still better – within the injectors.

Keywords: professor M.G. Kruglov, 100th anniversary, Bauman University, studies, educational work, titles and rewards, government service.

In September 2021 engine builders celebrated 100th anniversary of professor M.G. Kruglov, outstanding Russian scientist and statesman. Prof. M.G. Kruglov's learned works in the domain of combustion processes still remain actual and fundamental in training programs for highly skilled engine building specialists.

Keywords: marine engines, particulate matter emissions, particle size distribution measurement methods, various biofuels, oxygen concentration, reduction of particulate matter emissions.

The harmful exhaust gas emissions from marine diesel engines are NOx, SOx, and particulate matter. It is shown that lowering sulfur concentration in marine fuel results in lower emissions of РМ and black carbon. Presented are methods of РМ measurement and factors that may influence the measurement results. In this paper, particle size distribution and mass concentration of particulate matter from marine diesel engines were measured with 2 types of marine diesel engine, such as, high speed four-stroke engine (3L13AHS, 73.55 kW) and low speed two-stroke engine (3UEC33LSII-Eco, 1275 kW). The engines were fired with low-sulfur and high-sulfur MDO fuel. Furthermore, particle size distribution was measured by a hot-dilution method and a cooled dilution method. In the hot-dilution method, exhaust gas from the engine is diluted with high temperature air (in compliance with ISO 8178-1). Mass concentration of particulate matter was measured with the dilution tunnel system and divided into SOF (Soluble organic fraction) and ISF (Insoluble organic fraction) by Soxhlet extraction method, and PM particle size distribution was measured with the Scanning mobility particle sizer (SMPS-Scanning mobility particle sizer) and Electric low pressure impactor (ELPI-Electric low pressure impactor). The effects of the dilution ratio and the dilution air temperature in the dilution tunnel on particle size distribution and mass concentration of particulate matter were examined. The results of this experiment are as follows:
1.In the measurement by SMPS, the mode diameters of particle size of particulate matter from the marine diesel engines are below 100 nm for all experimental conditions.
2.Comparison of particulate size distributions by the hot dilution method and the cooled dilution method shows that a nucleation mode of volatility component within the particulate matter in the dilution tunnel is generated clearly.
3.For the two-stroke diesel engine, the mode diameter of particulate size become larger at high engine load condition, and this fact suggests that Brownian coagulation particulate matter has occurred.

The global warming problem caused by a large amount of discharged carbon dioxide from the use of fossil fuel required urgent measure to overcome this matter. In addition, the depletion of fossil fuel is thought as a huge problem for near future. Thus these problems have attracted many attentions of using biofuels especially that derived from vegetables oils as an alternative fuel for internal combustion engine. The authors conducted the systematic fundamental studies examining the spray combustion characteristics of biodiesels such as palm oil methyl ester (PME), coconut methyl ester (CME) and rapeseed methyl ester (RME) and reported in CIMAC 2010 and SETC 2013. However, as biodiesel consists of some kinds of fatty acid methyl ester (FAME), thus it is difficult to determine the major factor governing the combustion characteristics of biodiesels. Therefore, in the research in question different types of FAME which present in biodiesel were used. Following hydrogen combustion, fuel was injected into the vessel at the time when the ambient pressure reached the expected value, and the spray combustion was then examined. The fuel injection system used in the present study is an electronically controlled accumulator type fuel injection system developed by the authors. The ambient pressure and temperature were set to 3 MPa and 985 K. Spray combustion was photographed using the color high-speed video camera Though the soot yield increases as the ambient oxygen concentration decreases, FAMEs suppressed the amount of soot emission even at low ambient oxygen concentration due to its high oxygen content. Under the high temperature ambient condition around 1000 K, type of fuel and the mixing rates has small effect on the ignition delay.
The CIMAC papers are translated into Russian by G.Melnik, PhD.