Krylov State Research Center

Ice cover is one of the main parameters describing the state of various water areas. The simplicity of calculation determines the frequency of using the indicator in research both for reading the seasonal course and interannual changes in the state of the ice cover and for verifying model data or reanalysis data. In this paper, ice cover is calculated based on five data sources. The comparison is based on satellite data from the NSIDC DAAC archives (October 26, 1978, to March 31, 2023; spatial resolution is 25 × 25 km, temporal resolution is 1 day; the data were collected by SMMR, SSM/I, and SSMI/S sensors on the DMSP program satellites, as well as the Nimbus-7 satellite and OSISAF (product code OSI-401-d; March 1, 2005, to present; spatial resolution is 10 × 10 km and temporal resolution is 1 day; the data were collected by the SSMI/S sensor on the DMSP program satellites). Model data from the international CMIP (Coupled Model Intercomparison Project) project are used for comparison and verification. Of the more than 40 models of the sixth phase of the project, two were selected that provided the necessary data and were suitable in terms of spatial and temporal resolution: MPI-ESM1-2-HR and AWI-CM-1-1-MR of the Max Planck Institute and the Alfred Wegener Institute, respectively. For all obtained coverage series, the mean, standard deviation, range, correlation intervals, trend coefficients, and standard error were estimated relative to the NSIDC series for the data intersection period of September 19, 2016 to June 31, 2023, in each of the Russian Arctic seas, as well as for the water area as a whole. Using the statistical characteristics, satellite data on ice cover were compared with the results of modeling in accordance with different socioeconomic trajectories (Shared Socioeconomic Pathways (SSPs)) for both models, the quality of ice cover modeling was assessed, and scenarios were selected that most closely matched the satellite data for both the entire Russian Arctic water area and for individual seas. Based on the optimal scenarios, possible changes in ice content were predicted.

The results of experimental study of comparative efficiency of vibrational energy dissipation in materials of metal-polymer-metal (M–P–M) layered structure with different thickness of polymer layer are presented. It is shown that if the thickness of the polymer layer is significantly less than the thickness of the metal layer, it has little effect on the efficiency of energy dissipation in M–P–M structures. In addition, the vibration-absorbing film VPS-2.5 demonstrates high dissipation of vibrational energy in M–P–M structures in the frequency ranges from 1 to 6000 Hz, including low frequencies (f ≤ 200 Hz) even at a thickness of 0.2 mm.

The diagrams of ships ice propulsive quality allowing to determine all relevant parameters (power consumption, propeller RPM, movement speed and propulsion thrust) are described in the paper. These diagrams can be used to calculate above-mentioned ice propulsive quality parameters for the scenarios of high loads on propulsion system at low advance coefficients, like ice navigation and towing operations. It is pointed out that previously this calculation was impossible because of wake fractions tend to “minus infinity”. To overcome this challenge, an alternative (mooring) system of interaction coefficients briefly presented in this paper and enabling all required calculations, is developed and applied. The results of these calculations are presented in the form of ice propulsive quality diagrams that clearly and conveniently display the entire volume of the calculation data. It has been shown that ice propulsive quality diagrams can be easily added with the environmental data for usability. In the diagram given in this paper, the environmental parameter is the thickness of ice that the ship has to overcome. The possible practical applications for these diagrams, for instance ice resistance assessment during full-scale trials, are discussed in the paper. It is highlighted that the data contained in the ice propulsive quality diagrams are approximate. The possibility of using other environmental parameters is also discussed in the paper.

The experimental studies in the ice model tank of the Krylov State Research Centre are described in the paper. This study aimed at researching a possibility of close-coupled towing of large-sized vessels by icebreaker. The displacement of considered commercial vessels is several times greater than the icebreaker displacement. Due to the fact that an amount of cargo transported along the Northern Sea Route is growing every year and new terminals are being constructed for the export of raw materials extracted in the Arctic, it has been shown in the paper that new transport vessels with high cargo capacity should be designed and built for the efficient operation of terminal. It has also been shown that the organization of independent year-round operation of such vessels in the Arctic region is extremely difficult, therefore, even at the stage of their design it’s important to consider the possibility of their escorting by existing icebreakers. The feasibility of close-coupled towing in the escorting of large-sized vessels with low ice class by icebreakers in the Arctic waters has been studied in the paper. The models of the greatest existing nuclear-powered icebreaker and conditional bulk carrier are used as an object of the ice model tests. The study of the close-coupled towing features in the continuous flat ice conditions is carried out at straightforward movement and gyration, as well as for the case of an emergency stop of the icebreaker. During ice model tests the ice forces acting on the hull of the model are measured, as well as the load on a towing notch with rubber fenders in the stern of icebreaker and the tension in the wire rope. The comparison of the wire rope tension with its breaking force is taken as a criterion to assess the possibility of the close-coupled towing operation. The results can be used as the basis for choosing the hull concept of the future large-sized vessels, its ice class and main dimensions and in strategic simulations of Arctic marine transport systems.

Выполнено моделирование рабочих процессов судового дизельного двигателя MAN D&T серии MC с целью снижения выбросов диоксида углерода с отработавшими газами. Целью моделирования был поиск конструктивных и эксплуатационных решений, влияющих на эмиссию СO2. При выполнении расчетного исследования использовалась математическая модель комбинированного двигателя внутреннего сгорания, реализованная в компьютерной программе ДИЗЕЛЬ-РК. В качестве исследуемых переменных приняты степень сжатия, угол опережения и продолжительность впрыска топлива, значения которых можно устанавливать без внесения существенных изменений в конструкцию двигателя. Получены математические модели в виде уравнений регрессии, описывающие влияние исследуемых параметров подачи топлива (степень сжатия, угол опережения впрыска топлива и продолжительность впрыска топлива) на целевые функции – удельный выброс диоксида углерода и эффективная мощность дизельного двигателя 6S60MC. Для определения коэффициентов уравнения регрессии реализовано планирование полного факторного эксперимента второго порядка. С целью поиска минимального значения выбросов диоксида углерода используя метод обобщенного приведенного градиента решена задача выбора оптимальных значений степени сжатия, продолжительности впрыска топлива и угла опережения впрыска топлива для заданной эффективной мощности судового дизельного двигателя 6S60MC. Показано, что, например, при мощности двигателя 10000 кВт снижение выбросов диоксида углерода за счет оптимизации указанных параметров топливоподачи будет равно 7,37 %. The simulation of the working processes of the MAN D&T MC series marine diesel engine was carried out in order to reduce carbon dioxide emissions with exhaust gases. The purpose of the simulation was to find design and operational solutions that affect CO2 emissions. When performing a computational study, a mathematical model of a combined internal combustion engine implemented in the DIESEL-RK computer program was used. The studied variables are the compression ratio, the advance angle and the duration of fuel injection, the values ​​of which can be set without making significant changes to the engine design. Mathematical models are obtained in the form of regression equations that describe the effect of the studied fuel supply parameters (compression ratio, fuel injection advance angle and fuel injection duration) on the target functions - specific carbon dioxide emission and effective power of the 6S60MC diesel engine. To determine the coefficients of the regression equation, planning of a complete factorial experiment of the second order is implemented. In order to find the minimum value of carbon dioxide emissions using the generalized reduced gradient method, the problem of choosing the optimal values ​​of the compression ratio, fuel injection duration and fuel injection advance angle for a given effective power of a 6S60MC marine diesel engine is solved. It is shown that, for example, with an engine power of 10,000 kW, the reduction in carbon dioxide emissions by optimizing the specified fuel supply parameters will be 7.37%.

В статье рассмотрены особенности применения активированных окислительных технологий в судовых станциях приготовления питьевой воды. Рассмотрены процессы обеззараживания питьевой воды с использованием кавитации, УФ-излучения, озонирования. Показано, что применение перечисленных высокоэффективных процессов может значительно уменьшить потребность в реагентах, улучшить массогабаритные показатели, энергопотребление судовых станций приготовления питьевой воды. Предложено применение агрегата комплексного обеззараживания озонированием и УФ-излучением, совмещающего функции озонатора и устройства УФ-обеззараживания. Использование данного устройства сможет повысить надежность, ремонтопригодность, снизит массу, габариты, потребление электроэнергии станцией приготовления питьевой воды в целом. Обозначены достоинства и недоставки указанных способов обеззараживания питьевой воды. Обоснована функциональная схема станций приготовления питьевой воды с использованием синергетического эффекта активированных окислительных технологий. The article discusses the features of the use of activated oxidation technologies in ship stations for the preparation of drinking water. The processes of disinfection of drinking water using cavitation, UV-radiation, ozonation are considered. It is shown that the use of the listed highly efficient processes can significantly reduce the need for reagents, improve the weight and size indicators, and the energy consumption of ship drinking water preparation stations. The use of a unit for complex disinfection by ozonation and UV-radiation, which combines the functions of an ozonator and a UV-disinfection device, is proposed. The use of this device can increase reliability, maintainability, reduce weight, dimensions, and electricity consumption by the drinking water preparation station as a whole. The advantages and disadvantages of these methods of disinfection of drinking water are indicated. A functional diagram of drinking water preparation stations using the synergistic effect of activated oxidation technologies is substantiated. Keywords: drinking water disinfection, cavitation, UV-radiation, ozonation, ship water supply, activated oxidation technologies, drinking water preparation station, drinking water preparation technology.

Object and purpose of research. This paper discusses crash-stop of ship propellers. The puspose of the study was to investigate a number of relevant challenges in this process, i.e. to refine the methods of crash-stop distance calculation, to update the scenarios for which crash-stop strength of propeller blades has to be verified, as well as to determine operational parameters and algorithms for automatic control systems of electric power plants in crash-stop conditions. Subject matter and methods. The study was based on the results of quasi-crash-stop model tests, as well as on previous publications about crash-stop maneuvers of ships and operations of their propulsion systems in these conditions. Main results. To obtain more accurate crash-stop distance estimates, it was suggested to use an alternative, bollard-pull system of propeller-hull interaction coefficients for crash-stop conditions. It was also suggested to perform crash-stop strength check of propellers not only for the scenarios with maximum hydrodynamic load, but also for the moment of propeller rotation direction reversal because it might be accompanied by considerable inertial loads. It is shown that model testing is not helpful in determination of operational parameters and automatic control system algorithms for electric power plants because shaft lines cannot be simulated correctly. These parameters can be obtained through calculations, but this will require more refined expressions for shaft line friction moments. Conclusion. The actual problems of ship reverse propulsion theory is presented in the paper. The possible approaches to their solution are proposed.