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Rational Liquid Cooling Systems of Internal Combustion Engines

Moshentsev Yuryi, Gogorenko Oleksiy, Dvirna Olha

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 1

158--169

EN

The scheme of the cooling system is considered, which can be the basis for creating the most efficient cooling systems for IC engines of any purpose. It is assumed that the use of any other scheme is devoid of a rational basis. The scheme consists of two connected circulation circuits, in one of which the coolant flow rate is an order of magnitude less than in the second. The engine is included in a circuit with increased coolant flow. All heat exchangers are in the second circuit. Rules for the formation of such systems are formulated. The basis of the method for calculating such systems is considered. It is indicated that the flow rate through each heat exchanger must be determined by calculation to ensure the maximum efficiency of the cooling system. The considered scheme allows to provide the maximum possible depth of charge air cooling, if its temperature is not specified, or to ensure the minimum cost and compactness of the cooling system, if this temperature is known. The scheme allows regulating the temperatures of the cooling fluids of the system with all kinds of changes in the engine operating conditions and the ambient temperature.

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Possibilities for Improving the Cooling Systems of IC Engines of Marine Power Plants

Moshentsev Yuryi, Gogorenko Oleksiy, Dvirna Olha

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 3

183--192

EN

Modern cooling systems for large ships are quite complex. As a rule, such systems are common (combined) for the main and auxiliaries engines. With the auxiliary engines running constantly, even when parked, this system design allows to keep it warm and ready for a quick start of the main engines at any time. Currently, various schemes of such systems are used, including those that are irrational from our point of view. At the same time, there are systems whose schemes are quite consistent with our idea of the rational forms of such structures. It is important to note, and it is saying about it in an article, that such schemes may have a number of significant differences, but at the same time they will comply with the rationality principle if certain rules for the formation of such systems are followed. These schemes will have close compactness. It is also important that there is the possibility of further improvement of such schemes based on certain rules. This improvement is possible due to the introduction of additional heat dissipaters and the organization of appropriate chains of heat sources and heat dissipaters. The article discusses various options for rational schemes of the cooling system for the same ship power plant, as well as the possibility of further improvement of this scheme. It is shown that an increase in the number of coolants of the internal circuit coolant from one to three can reduce the total mass of the heat exchanger cores by 18 %.

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The development of long-range heat transfer surfaces for marine diesel engine charge air coolers

Kuznetsov Valerii, Gogorenko Oleksiy, Kuznetsova Svetlana

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2021

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nr 65 (137)

51--57

EN

Charge air cooling is essential for the efficient operation of marine diesel engines. This work presents the results of research on the characteristics of long-range heat transfer surfaces for marine diesel engines. Elliptical and flat-oval tubes were considered. This study was carried out using mathematical models that consisted of the equations for energy conservation, motion, continuity, and state. The RSM turbulence model was used to close the system of equations. To solve the resulting system of equations, the RANS approach was used, which was implemented in the software package Code Saturne with a free license and the SimScale cloud service. The mathematical model was verified by comparing the model results with the experimental results obtained using a prototype heat-exchange surface of a charge air cooler at a test bench. The discrepancy between the theoretical and experimental heat transfer coefficient α was ≤ 8.3%. An estimate of the compactness of smooth elliptical and flat-oval tube banks compared with round ones was carried out. A 19.6% increase in compactness was obtained for elliptical tubes and 17.5% for flat-oval tubes. Based on the profiled finning surfaces, it is possible to improve their thermohydraulic characteristics by up to 40% when using them together with elliptical tubes compared with round ones and up to 26% when using them with flat-oval tubes.

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An influence of fouling gathered on the heat transfer surfaces on the heat performance characteristics of the ship steam systems' heat exchangers

Hajduk T.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2021

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Vol. 15 No. 1

183--189

EN

More than half of the incidents reported to EMSA relate to nautical events such as collision, groundings and contacts. Knowledge of accurate and high-integrity positioning is therefore not only a need for future automated shipping but a base for today’s safe navigation. Examples on accidents include Ever Given in the Suez Canal and HNoMS Helge Ingstad in Norway. A Network-RTK (NRTK) service can be used as an augmentation technique to improve performance of shipborne GNSS receivers for future positioning of manned and unmanned vessels in restricted areas, such as port areas, fairways, and inland water ways. NRTK service providers generate RTK corrections based on the observations of networks of GNSS reference stations which enables the users to determine their position with centimeter accuracy in real-time using a shipborne GNSS receiver. Selection of appropriate communication channels for dissemination of NRTK corrections data is the key to a secure positioning (localization) service. In PrePare-Ships project, the modern maritime communication system VDES (VHF Data Exchange System) is proposed to distribute SWEPOS (NRTK in Sweden) correction data to shipborne positioning modules. VDES is a very reliable technique and it is compatible with most onboard functionalities. In order to minimize the impact on the overall VDES data capacity in a local area, NRTK correction data shall only occupy a single VDES slot with a net capacity of 650 bytes. Update rates may vary but are preferably at 1Hz. However, NRTK correction data size changes instantly, depending on the number of visible GNSS satellites, and the data rate can therefore sometimes reach in excess of 1000 byte/s. In this study, a smart technique is proposed to reduce size of NRTK correction data to instantly adapt with the VDES requirements by choosing a combination of specific signals, satellites or even constellations such that the data rate is not more than 650 byte/s, and at the same time it achieves optimal positioning performance with the accuracy required by the PrePare-Ships project application.