Risk ranking of maintenance activities in a two-stroke marine diesel engine via fuzzy AHP method

2021 ◽  
Vol 111 ◽  
pp. 102648
Author(s):  
Bedir Ünver ◽  
İsmail Altın ◽  
Samet Gürgen
Keyword(s):  
Diesel Engine ◽  
Fuzzy Ahp ◽  
Marine Diesel Engine ◽  
Ahp Method ◽  
Risk Ranking ◽  
Marine Diesel ◽  
Maintenance Activities

Selection of a Waste Heat Recovery System for a Marine Diesel Engine Based on Exergy Analysis

2016 ◽  
Vol 25 ◽  
pp. 36-51
Author(s):  
Salman Abdu ◽  
Song Zhou ◽  
Malachy Orji
Keyword(s):  
Diesel Engine ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Marine Diesel Engine ◽  
Exergetic Efficiency ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System ◽  
Marine Diesel

Highly increased fuel prices and the need for greenhouse emissions reduction from diesel engines used in marine engines in compliance with International Maritime Organization (IMO) on the strict regulations and guidelines for the Energy Efficiency Design Index (EEDI) make diesel engine exhaust gas heat recovery technologies attractive. The recovery and utilization of waste heat not only conserves fuel, but also reduces the amount of waste heat and greenhouse gases dumped to the environment .The present paper deals with the use of exergy as an efficient tool to measure the quantity and quality of energy extracted from waste heat exhaust gases in a marine diesel engine. This analysis is utilized to identify the sources of losses in useful energy within the components of the system for three different configurations of waste heat recovery system considered. The second law efficiency and the exergy destroyed of the components are investigated to show the performance of the system in order to select the most efficient waste heat recovery system. The effects of ambient temperature are also investigated in order to see how the system performance changes with the change of ambient temperature. The results of the analysis show that in all of the three different cases the boiler is the main source of exergy destruction and the site of dominant irreversibility in the whole system it accounts alone for (31-52%) of losses in the system followed by steam turbine and gas turbine each accounting for 13.5-27.5% and 5.5-15% respectively. Case 1 waste heat recovery system has the highest exergetic efficiency and case 3 has the least exergetic efficiency.

Stress Distribution Analysis on Alloy Layer of High Power Marine Diesel Engine Bearing Bush

2013 ◽  
Vol 331 ◽  
pp. 148-152
Author(s):  
Xiu Xu Zhao ◽  
Zhi Xiang Hu ◽  
An Jian Huang
Keyword(s):  
Diesel Engine ◽  
High Power ◽  
Alloy Layer ◽  
Marine Diesel Engine ◽  
Oil Film ◽  
Marine Diesel ◽  
Bearing Alloy ◽  
Stress And Strain Distribution ◽  
Engine Bearing ◽  
Oil Film Pressure

According to the characteristics of large size, small clearance ratio, high oil film pressure and thin oil film thickness in the actual conditions of high power marine diesel engine bearing, this Paper analyzes oil film pressure distribution on inner surface of bearing bush based on the finite difference method, uses finite element method to establish the hierarchical model, and analyzes stress and strain distribution on bearing alloy. In addition, this Paper researches the changes of stress and strain distribution on bearing alloy layer when alloy layer thickness changes for the optimization design of high power marine diesel engine bearing bush.

Modeling and performance analysis of diesel engine considering the heating effect of blow-by on cylinder intake gas

2021 ◽  
pp. 146808742110692
Author(s):  
Zhenyu Shen ◽  
Yanjun Li ◽  
Nan Xu ◽  
Baozhi Sun ◽  
Yunpeng Fu ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Engine Performance ◽  
Marine Diesel Engine ◽  
Heating Effect ◽  
Shipping Industry ◽  
Low Speed ◽  
Proposed Model ◽  
International Regulations ◽  
Marine Diesel ◽  
And Performance

Recently, the stringent international regulations on ship energy efficiency and NOx emissions from ocean-going ships make energy conservation and emission reduction be the theme of the shipping industry. Due to its fuel economy and reliability, most large commercial vessels are propelled by a low-speed two-stroke marine diesel engine, which consumes most of the fuel in the ship. In the present work, a zero-dimensional model is developed, which considers the blow-by, exhaust gas bypass, gas exchange, turbocharger, and heat transfer. Meanwhile, the model is improved by considering the heating effect of the blow-by gas on the intake gas. The proposed model is applied to a MAN B&W low-speed two-stroke marine diesel engine and validated with the engine shop test data. The simulation results are in good agreement with the experimental results. The accuracy of the model is greatly improved after considering the heating effect of blow-by gas. The model accuracy of most parameters has been improved from within 5% to within 2%, by considering the heating effect of blow-by gas. Finally, the influence of blow-by area change on engine performance is analyzed with considering and without considering the heating effect of blow-by.

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