Journal of Marine Science and Engineering

Editorial

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5 pages, 178 KiB

Open AccessEditorial

Marine Power Systems

by Igor Poljak

J. Mar. Sci. Eng. 2022, 10(2), 195; https://doi.org/10.3390/jmse10020195 - 01 Feb 2022

Cited by 2 | Viewed by 1317

Abstract

The international seaborne trade by volume is divided into 60% loaded and 70% discharged trade, which means that the marine industry today is still the number one means of transportation for the human kind [...] Full article

(This article belongs to the Special Issue Marine Power Systems)

Research

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32 pages, 9422 KiB

Open AccessArticle

Energy, Economic and Environmental Effects of the Marine Diesel Engine Trigeneration Energy Systems

by Ivan Gospić, Ivica Glavan, Igor Poljak and Vedran Mrzljak

J. Mar. Sci. Eng. 2021, 9(7), 773; https://doi.org/10.3390/jmse9070773 - 16 Jul 2021

Cited by 9 | Viewed by 2357

Abstract

The paper discusses the possibility of applying the trigeneration energy concept (cogeneration + absorption cooling) on diesel-powered refrigerated ships, based on systematic analyses of variable energy loads during the estimated life of the ship on a predefined navigation route. From a methodological point [...] Read more.

The paper discusses the possibility of applying the trigeneration energy concept (cogeneration + absorption cooling) on diesel-powered refrigerated ships, based on systematic analyses of variable energy loads during the estimated life of the ship on a predefined navigation route. From a methodological point of view, mathematical modeling of predictable energy interactions of a ship with a realistic environment yields corresponding models of simultaneously occurring energy loads (propulsion, electrical and thermal), as well as the preferred trigenerational thermal effect (cooling and heating). Special emphasis is placed on the assessment of the upcoming total heat loads (refrigeration and heating) in live cargo air conditioning systems (unfrozen fruits and vegetables) as in ship accommodations. The obtained results indicate beneficiary energy, economic and environmental effects of the application of diesel engine trigeneration systems on ships intended for cargo transport whose storage temperatures range from −25 to 15 °C. Further analysis of trigeneration system application to the passenger ship air conditioning system indicates even greater achievable savings. Full article

(This article belongs to the Special Issue Marine Power Systems)

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18 pages, 7519 KiB

Open AccessArticle

Research on Improving the Working Efficiency of Hydraulic Jet Submarine Cable Laying Machine

by Zhifei Lu, Chen Cao, Yongqiang Ge, Jiamin He, Zhou Yu, Jiawang Chen and Xinlong Zheng

J. Mar. Sci. Eng. 2021, 9(7), 745; https://doi.org/10.3390/jmse9070745 - 05 Jul 2021

Cited by 6 | Viewed by 2213

Abstract

The anchoring and hooking of ships, bedrock friction and biological corrosion threaten the safety and stability of submarine cables. A hydraulic jet submarine cable laying machine manages to bury the submarine cables deep into the seabed, and effectively reduces the occurrence of external [...] Read more.

The anchoring and hooking of ships, bedrock friction and biological corrosion threaten the safety and stability of submarine cables. A hydraulic jet submarine cable laying machine manages to bury the submarine cables deep into the seabed, and effectively reduces the occurrence of external damage to the submarine cables. This machine uses a hydraulic jet system to realize trenching on the seabed. However, the hydraulic jet submarine cable laying machine has complicated operation and high power consumption with high requirements on the mother ship, and it is not yet the mainstream trenching method. In this paper, a mathematical model for the hydraulic jet nozzle of the submarine cable laying machine is established, and parameters that affect the trenching efficiency are studied. The effects of jet target distance, flow, angle and nozzle spacing on the working efficiency of the burying machine are analyzed by setting up a double-nozzle model. The results of the theory, numerical simulation and experiment show that the operational efficiency of the hydraulic jet submarine cable laying machine can be distinctly improved by setting proper jet conditions and parameters. Full article

(This article belongs to the Special Issue Marine Power Systems)

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31 pages, 7569 KiB

Open AccessArticle

Use of Genetic Programming for the Estimation of CODLAG Propulsion System Parameters

by Nikola Anđelić, Sandi Baressi Šegota, Ivan Lorencin, Igor Poljak, Vedran Mrzljak and Zlatan Car

J. Mar. Sci. Eng. 2021, 9(6), 612; https://doi.org/10.3390/jmse9060612 - 02 Jun 2021

Cited by 6 | Viewed by 2661

Abstract

In this paper, the publicly available dataset for the Combined Diesel-Electric and Gas (CODLAG) propulsion system was used to obtain symbolic expressions for estimation of fuel flow, ship speed, starboard propeller torque, port propeller torque, and total propeller torque using genetic programming (GP) [...] Read more.

In this paper, the publicly available dataset for the Combined Diesel-Electric and Gas (CODLAG) propulsion system was used to obtain symbolic expressions for estimation of fuel flow, ship speed, starboard propeller torque, port propeller torque, and total propeller torque using genetic programming (GP) algorithm. The dataset consists of 11,934 samples that were divided into training and testing portions in an 80:20 ratio. The training portion of the dataset which consisted of 9548 samples was used to train the GP algorithm to obtain symbolic expressions for estimation of fuel flow, ship speed, starboard propeller, port propeller, and total propeller torque, respectively. After the symbolic expressions were obtained the testing portion of the dataset which consisted of 2386 samples was used to measure estimation performance in terms of coefficient of correlation (

R^{2}

) and Mean Absolute Error (

M A E

) metric, respectively. Based on the estimation performance in each case three best symbolic expressions were selected with and without decay state coefficients. From the conducted investigation, the highest

R^{2}

and lowest

M A E

values were achieved with symbolic expressions for the estimation of fuel flow, ship speed, starboard propeller torque, port propeller torque, and total propeller torque without decay state coefficients while symbolic expressions with decay state coefficients have slightly lower estimation performance. Full article

(This article belongs to the Special Issue Marine Power Systems)

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12 pages, 3956 KiB

Open AccessArticle

Verification of Vibration Isolation Effectiveness of the Underwater Vehicle Power Plant

by Yang Yang, Guang Pan, Shaoping Yin, Ying Yuan and Qiaogao Huang

J. Mar. Sci. Eng. 2021, 9(4), 382; https://doi.org/10.3390/jmse9040382 - 03 Apr 2021

Cited by 10 | Viewed by 2294

Abstract

In order to enhance the vibration isolation effectiveness of an underwater vehicle power plant, and alleviate the mechanical vibration of the outer housing, initially discrete vibration isolators were improved, and three new types of ring vibration isolators designed, i.e., ring metal rubber isolators, [...] Read more.

In order to enhance the vibration isolation effectiveness of an underwater vehicle power plant, and alleviate the mechanical vibration of the outer housing, initially discrete vibration isolators were improved, and three new types of ring vibration isolators designed, i.e., ring metal rubber isolators, magnesium alloy isolators and modified ultra-high polyethylene isolators (MUHP). A vibrator excitation test was carried out, and the isolation effectiveness of the three types of vibration isolators was evaluated, adopting insertion loss and vibration energy level drop. The results showed that compared with the initial isolators and the other two new types of isolators, MUHP showed the most significant vibration isolation effectiveness. Furthermore, its effectiveness was verified by a power vibration test of the power plant. To improve the vibration isolation effectiveness, in addition to vibration isolators, it is essential to carry out investigations on high-impedance housings. Full article

(This article belongs to the Special Issue Marine Power Systems)

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19 pages, 2442 KiB

Open AccessArticle

Fault Tree Analysis and Failure Diagnosis of Marine Diesel Engine Turbocharger System

by Vlatko Knežević, Josip Orović, Ladislav Stazić and Jelena Čulin

J. Mar. Sci. Eng. 2020, 8(12), 1004; https://doi.org/10.3390/jmse8121004 - 09 Dec 2020

Cited by 32 | Viewed by 8839

Abstract

The reliability of marine propulsion systems depends on the reliability of several sub-systems of a diesel engine. The scavenge air system is one of the crucial sub-systems of the marine engine with a turbocharger as an essential component. In this paper, the failures [...] Read more.

The reliability of marine propulsion systems depends on the reliability of several sub-systems of a diesel engine. The scavenge air system is one of the crucial sub-systems of the marine engine with a turbocharger as an essential component. In this paper, the failures of a turbocharger are analyzed through the fault tree analysis (FTA) method to estimate the reliability of the system and to predict the cause of failures. The quantitative method is used for assessing the probability of faults occurring in the turbocharger system. The main failures of a scavenge air sub-system, such as air filter blockage, compressor fouling, turbine fouling (exhaust side), cooler tube blockage and cooler air side blockage, are simulated on a Wärtsilä-Transas engine simulator for a marine two-stroke diesel engine. The results obtained through the simulation can provide improvement in the maintenance plan, reliability of the propulsion system and optimization of turbocharger operation during exploitation time. Full article

(This article belongs to the Special Issue Marine Power Systems)

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37 pages, 12667 KiB

Open AccessFeature PaperArticle

Improvement of Marine Steam Turbine Conventional Exergy Analysis by Neural Network Application

by Sandi Baressi Šegota, Ivan Lorencin, Nikola Anđelić, Vedran Mrzljak and Zlatan Car

J. Mar. Sci. Eng. 2020, 8(11), 884; https://doi.org/10.3390/jmse8110884 - 05 Nov 2020

Cited by 22 | Viewed by 4494

Abstract

This article presented an improvement of marine steam turbine conventional exergy analysis by application of neural networks. The conventional exergy analysis requires numerous measurements in seven different turbine operating points at each load, while the intention of MLP (Multilayer Perceptron) neural network-based analysis [...] Read more.

This article presented an improvement of marine steam turbine conventional exergy analysis by application of neural networks. The conventional exergy analysis requires numerous measurements in seven different turbine operating points at each load, while the intention of MLP (Multilayer Perceptron) neural network-based analysis was to investigate the possibilities for measurements reducing. At the same time, the accuracy and precision of the obtained results should be maintained. In MLP analysis, six separate models are trained. Due to a low number of instances within the data set, a 10-fold cross-validation algorithm is performed. The stated goal is achieved and the best solution suggests that MLP application enables reducing of measurements to only three turbine operating points. In the best solution, MLP model errors falling within the desired error ranges (Mean Relative Error) MRE < 2.0% and (Coefficient of Correlation) R² > 0.95 for the whole turbine and each of its cylinders. Full article

(This article belongs to the Special Issue Marine Power Systems)

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22 pages, 6257 KiB

Open AccessArticle

Analysis of the Impact of Split Injection on Fuel Consumption and NO_x Emissions of Marine Medium-Speed Diesel Engine

by Vladimir Pelić, Tomislav Mrakovčić, Radoslav Radonja and Marko Valčić

J. Mar. Sci. Eng. 2020, 8(10), 820; https://doi.org/10.3390/jmse8100820 - 20 Oct 2020

Cited by 11 | Viewed by 2890

Abstract

The medium-speed diesel engine in diesel-electric propulsion systems is increasingly used as the propulsion engine for liquefied natural gas (LNG) ships and passenger ships. The main advantage of such systems is high reliability, better maneuverability, greater ability to optimize and significant decreasing of [...] Read more.

The medium-speed diesel engine in diesel-electric propulsion systems is increasingly used as the propulsion engine for liquefied natural gas (LNG) ships and passenger ships. The main advantage of such systems is high reliability, better maneuverability, greater ability to optimize and significant decreasing of the engine room volume. Marine propulsion systems are required to be as energy efficient as possible and to meet environmental protection standards. This paper analyzes the impact of split injection on fuel consumption and NO_x emissions of marine medium-speed diesel engines. For the needs of the research, a zero-dimensional, two-zone numerical model of a diesel engine was developed. Model based on the extended Zeldovich mechanism was applied to predict NO_x emissions. The validation of the numerical model was performed by comparing operating parameters of the basic engine with data from engine manufacturers and data from sea trials of a ship with diesel-electric propulsion. The applicability of the numerical model was confirmed by comparing the obtained values for pressure, temperature and fuel consumption. The operation of the engine that drives synchronous generator was simulated under stationary conditions for three operating points and nine injection schemes. The values obtained for fuel consumption and NO_x emissions for different fuel injection schemes indicate the possibility of a significant reduction in NO_x emissions but with a reduction in efficiency. The results showed that split injection with a smaller amount of pilot fuel injected and a smaller angle between the two injection allow a moderate reduction in NO_x emissions without a significant reduction in efficiency. The application of split injection schemes that allow significant reductions in NO_x emissions lead to a reduction in engine efficiency. Full article

(This article belongs to the Special Issue Marine Power Systems)

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15 pages, 4626 KiB

Open AccessArticle

Performance Analysis of Combined Cycle with Air Breathing Derivative Gas Turbine, Heat Recovery Steam Generator, and Steam Turbine as LNG Tanker Main Engine Propulsion System

by Wahyu Nirbito, Muhammad Arif Budiyanto and Robby Muliadi

J. Mar. Sci. Eng. 2020, 8(9), 726; https://doi.org/10.3390/jmse8090726 - 20 Sep 2020

Cited by 13 | Viewed by 4445

Abstract

This study explains the performance analysis of a propulsion system engine of an LNG tanker using a combined cycle whose components are gas turbine, steam turbine, and heat recovery steam generator. The researches are to determine the total resistance of an LNG tanker [...] Read more.

This study explains the performance analysis of a propulsion system engine of an LNG tanker using a combined cycle whose components are gas turbine, steam turbine, and heat recovery steam generator. The researches are to determine the total resistance of an LNG tanker with a capacity of 125,000 m³ by using the Maxsurf Resistance 20 software, as well as to design the propulsion system to meet the required power from the resistance by using the Cycle-Tempo 5.0 software. The simulation results indicate a maximum power of the system of about 28,122.23 kW with a fuel consumption of about 1.173 kg/s and a system efficiency of about 48.49% in fully loaded conditions. The ship speed can reach up to 20.67 knots. Full article

(This article belongs to the Special Issue Marine Power Systems)

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19 pages, 2565 KiB

Open AccessArticle

Analysis and Optimization of Atmospheric Drain Tank of Lng Carrier Steam Power Plant

by Igor Poljak, Toni Bielić, Vedran Mrzljak and Josip Orović

J. Mar. Sci. Eng. 2020, 8(8), 568; https://doi.org/10.3390/jmse8080568 - 28 Jul 2020

Cited by 6 | Viewed by 3695

Abstract

The atmospheric drain condensate system of a marine steam power plant is described and evaluated from the energetic and exergetic point of view at a conventional liquefied natural gas (LNG) carrier. Energy loss and exergy destruction rate were calculated for individual stream flows [...] Read more.

The atmospheric drain condensate system of a marine steam power plant is described and evaluated from the energetic and exergetic point of view at a conventional liquefied natural gas (LNG) carrier. Energy loss and exergy destruction rate were calculated for individual stream flows joined in an atmospheric drain tank with variations of the main turbine propulsion speed rate. The energy efficiency of joining streams was noted to be above 98% at all observed points as the atmospheric drain tank was the direct heater. The exergy efficiency of the stream flows into the drain tank was in the range of 80% to 90%. The exergy stream flow to the tank was modeled and optimized by the gradient reduced gradient (GRG) method. Optimization variables comprised contaminated and clean condensate temperature of the atmospheric drain tank and distillate water inlet to the atmospheric drain tank with respect to condensate outlet temperature. The optimal temperatures improves the exergy efficiency of the tank as direct heater, to about 5% in port and 3% to 4% when the LNG carrier was at sea, which is the aim of optimizing. Proposals for improvement and recommendations are given for proper plant supervision, which may be implemented in real applications. Full article

(This article belongs to the Special Issue Marine Power Systems)

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Review

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13 pages, 6887 KiB

Open AccessReview

Marine Propulsion System Failures—A Review

by Goran Vizentin, Goran Vukelic, Lech Murawski, Naman Recho and Josip Orovic

J. Mar. Sci. Eng. 2020, 8(9), 662; https://doi.org/10.3390/jmse8090662 - 27 Aug 2020

Cited by 26 | Viewed by 7340

Abstract

Failures of marine propulsion components or systems can lead to serious consequences for a vessel, cargo and the people onboard a ship. These consequences can be financial losses, delay in delivery time or a threat to safety of the people onboard. This is [...] Read more.

Failures of marine propulsion components or systems can lead to serious consequences for a vessel, cargo and the people onboard a ship. These consequences can be financial losses, delay in delivery time or a threat to safety of the people onboard. This is why it is necessary to learn about marine propulsion failures in order to prevent worst-case scenarios. This paper aims to provide a review of experimental, analytical and numerical methods used in the failure analysis of ship propulsion systems. In order to achieve that, the main causes and failure mechanisms are described and summarized. Commonly used experimental, numerical and analytical tools for failure analysis are given. Most indicative case studies of ship failures describe where the origin of failure lies in the ship propulsion failures (i.e., shaft lines, crankshaft, bearings, foundations). In order to learn from such failures, a holistic engineering approach is inevitable. This paper tries to give suggestions to improve existing design procedures with a goal of producing more reliable propulsion systems and taking care of operational conditions. Full article

(This article belongs to the Special Issue Marine Power Systems)

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