The All-British High-Powered Marine Diesel Engine

1975 ◽  
Vol 189 (1) ◽  
pp. 21-32
Author(s):  
J. F. Butler

Over the past quarter of a century, British-designed marine propulsion diesel engines have more than doubled their power output per cylinder. During the same period weight per kilowatt, and engine length per kilowatt, have both been reduced by nearly 75 per cent, specific fuel consumption has been reduced, and reliability has improved. This progress has been achieved by detail design improvements to even out stresses in components and to reduce temperature differences between hot and cold surfaces, combined with the application of the results of advanced computer methods to air flow, fuel distribution, and separation of rubbing surfaces by oil films. At the present stage of development the marine diesel engine is in many ways more advanced than the small automotive engine and can also compete in economic power production with prime movers at the opposite end of the scale such as super-large high-pressure steam turbines.

Author(s):  
D. C. Lee ◽  
J. D. Yu

Under steady state condition, unstable torsional vibration normally does not occur in shafting systems using 4stroke diesel engine due to hysteresis damping of shafting system and relative damping of standard fitted damper. However, the unstable torsional vibration occurs on marine propulsion shafting systems due to slippage of a multi-friction clutch installed between increasing gear box and shaft generator. To identify this unstable vibration and make proper counter measure, the simulation for transient torsional vibration using the Newmark method is introduced in this paper. The mechanism of this unstable vibration is verified by vibration and noise measurements of the shafting system.


2020 ◽  
Vol 3 (3) ◽  
pp. 359-372
Author(s):  
Vladimir Pelić ◽  
Tomislav Mrakovčić ◽  
Ozren Bukovac ◽  
Marko Valčić

Increasing demands on energy efficiency and environmental acceptance are being imposed on marine propulsion plants. The fulfilment of the conditions set by the MARPOL Convention, Annex VI, regarding the emissions from exhaust gases of marine diesel engines is of particular interest. This paper presents the development and validation of a zero-dimensional, single-zone diesel engine numerical model. Presented numerical model is based on the law of conservation of energy and mass and solving the resulting differential equations. The single-zone model will serve as the basis for a model where the cylinder space is divided into two or three zones during combustion. In this way, the multi-zone model will allow the modelling of nitrogen oxide emissions with satisfactory accuracy. Validation of the diesel engine model was carried out for the Wärtsilä 12V50DF 11700 kW motor designed to drive a synchronous alternator. Obtained results and deviations of certain parameters in the operation of the engine with respect to the data obtained from the measurements on the test bed, are more than satisfactory regarding complexity of the numerical model. This confirmed the usability of the model for research purposes to optimize the marine diesel engine.


Author(s):  
Salman Abdu ◽  
Song Zhou ◽  
Malachy Orji

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.


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