Paper 6: Alignment Investigation following a Medium-Speed Marine Engine Crankshaft Failure

Author(s):  
D. Castle

The multiple fracture, apparently without warning, of the crankshaft of one of a pair of medium-speed propulsion engines in a modern cargo ship in mid-Atlantic led to a programme of tests, involving many alignment measurements, chiefly on a sister ship. The damage to the engine is reviewed and an account is given of the investigation into the cause of failure. The measured values of alignment are recorded, together with changes of alignment due to temperature variations of the machinery, the lubricating oil, and the cooling water, and to cargo loading and distribution. Conclusions are stated and a set of rules, which have been supported by subsequent experience, are postulated.

Author(s):  
John Hedrick ◽  
Steven G. Fritz ◽  
Ted Stewart

This paper focuses on quantifying emission reductions associated with various on-engine technologies applied to Electro-Motive Diesel two-cycle diesel engines, which are very popular in marine and locomotive applications in North America. This paper investigates the benefits of using exhaust gas recirculation (EGR), separate circuit aftercooler, and retarded injection timing on a EMD 12-645E7 marine engine. The EGR system alone provided up to a 32.9% reduction in brake specific Nitrogen Oxides (NOx) emissions while demonstrating less than one percent increase in cycle brake specific fuel consumption (BSFC). The brake specific particulate matter emissions increased somewhat, but at a modest rate based on the amount of NOx emission reduction. When the enhanced aftercooler system was combined with the addition of EGR, there was a 31.9% reduction in NOx and essentially no change to the BSFC when compared to the baseline test. The minimum manifold air temperature (MAT) was limited due to the size of the standard EMD aftercooler heat exchanger that is fitted on the engine. No efforts to modify the turbocharger to improve the turbo match to take advantage of the lower manifold air temperatures and the corresponding lower exhaust energy. Once 4° static injection timing retard was introduced, along with the EGR and the minimum MAT, a maximum NOx reduction of 49% was realized with only a 1.1% increase over the baseline BSFC.


2015 ◽  
Vol 236 ◽  
pp. 85-92 ◽  
Author(s):  
Jerzy Merkisz ◽  
Jarosław Markowski ◽  
Jarosław Kaluzny ◽  
Robert Roszak

Engine operating conditions of the main propulsion, static in principle with steady-state rotation speed of the crankshaft and engine load, also work under dynamic load conditions. These conditions cause additional distortion of the crankshaft and changes in the operating conditions of the shaft bearings. However, the greatest impact on the long and trouble-free operation has proper engine maintenance. Variable operating conditions and engine operating errors, unfortunately, often cause damage to the main bearings of the crankshaft. Repair of the damaged main bearing spindles of the shaft involves performing the machining of the spindle surface then its re-hardening and selecting new bearing bushings with the appropriate bearing clearance. Trusting the engine manufacturer, there is no check of the influence of the machining of bearing spindles on the structural properties of the shaft. Therefore, the paper presents the model tests of the structure of medium-rev marine engine crankshaft aimed at determining the changes in the mechanical properties of the structure resulting from carrying out the regeneration of the main shaft spindles.


Author(s):  
Vasiliy Aleksandrovich Chanchikov ◽  
Ivan Nikolaevich Guzhvenko ◽  
Alexandr Ivanovich Andreev ◽  
Marina Aleksandrovna Shulimova ◽  
Sergey Aleksandrovich Svekolnykov

The paper presents the results of studying the influence of variable characteristics of lubricating oils for marine diesel engines (concentration of layered friction modifier in lubricating oil, viscosity of lubricating oil, contact pressure in the friction zone) on the tribological parameters of parts of the cylinder-piston group of marine diesel engines. There are considered the aspects of increasing the reliability and wear resistance of the cylinder-piston group of marine diesel engines when a layered friction modifier is added to the base lubricating oil in a concentration of 1.5 vol.%. There have been carried out the comparative tribological studies of M-16G2CS lubricating oil including an additive based on molybdenum diselenide. Dependences of the wear of parts of the cylinder-piston group of a marine engine on different parameters of the studied lubricants are shown. The wear rate of experimental samples in conditions of variable characteristics of lubricants has been studied. According to the tribological studies of lubricants and structural materials, the tribological rating of lubricating compositions containing M16G2CS marine engine oil as a base and a layered friction modifier - molybdenum diselenide as a tribologically active additive was built. The test tool for the antiwear ability of lubricants is a friction machine of an original design with abraded samples according to the “ball-cylinder” contact scheme. Mechanical mixing of the lubricating medium of “oil + additive” type on the RPU-0.8-55A rotary-pulsating unit was one of the variable parameters in the tests. The tribological efficiency of the studied antiwear additive varies depending on the type of mixing of the additive solution before adding to the base lubricating oil and makes 13-54% (the difference in the diameter of the wear spot of the sample) for mechanical mixing, and for rotary-pulsation mixing - 45-56%.


Author(s):  
M. Cipolla

A typical industrial application of high temperature pumps involves handling of fluids up to 400 °C. This is critical for pump bearing housing, where thermal dissipation is not effective due to geometric configuration. Therefore, without any external cooling system, bearings and lubricating oil temperatures can exceed allowable values prescribed by both API 610 Reference Standard [1] and bearing manufacturer [2]. Particularly, for a overhung pump, when pumped fluid temperature is above 200 °C, external cooling system is necessary and water is usually used for this purpose. Consequently, water availability must be taken into account when considering pump’s location, which is particularly difficult in desert areas. From these considerations was the idea to enhance the heat transfer of the pump support, in order to avoid any need of cooling water. The problem has been dealt with numerical analysis and experimental tests. First, we have considered the original support in the most critical situation, the stand-by condition, where no forced convection (fan) is effective. From the results pertaining to currently used support, we have got the hints to improve heat transfer by a full redesign. Finally an experimental validation has been set up. The measures gained allow us to validate hypothesis taken into consideration in the numerical simulation.


2001 ◽  
Author(s):  
Dong Woon Jeong ◽  
Sang Yong Lee ◽  
Byung Kyu Park

Abstract A simulation program taking into account of the mass transfer effect was constructed to estimate the heat transfer rate and the pressure drop of a flow of humid flue gas across a tube bank. Higher heat transfer rate is expected when the flue gas temperature drops below the dew point because of the vapor condensation effect at the external surface of the tubes. The temperature variations of the flue gas and the cooling water and the pressure drop across the tube bank were compared with the experimental data reported previously. The predicted results for the temperature variations without any correction factor agree satisfactorily with the experimental data. As for the shell-side pressure drop, the single-phase friction factor for the tube-bank flow adopted. With this simulation program, the parametric studies have been conducted for various operating conditions, such as the velocities and temperatures of the vapor/gas mixture and the cooling water, the number of the tube-rows, and the conductivity of the wall material.


2013 ◽  
Vol 634-638 ◽  
pp. 1677-1681 ◽  
Author(s):  
Zhou Ping Li ◽  
Xiao Jian Hu ◽  
Hai Yan Ma ◽  
Si Wei Yan ◽  
Ai Jun Yan ◽  
...  

The plate heat exchanger in oil cooler of unit 2 in a thermal power plant became corrosion perforation after 2-year running, and severe pits were found on its surface. The material and scale composition of the lubricating oil cooler was analyzed, and it was found that the oil cooler was made of 304 stainless steel, instead of the 316 stainless steel provided by factory. The corrosion products on the corroded surface were composed of some characteristic elements in cooling water. The analysis suggested that the reason for corrosion perforation of the heat exchanger could be associated with its material composition, and the under scale corrosion formed under the action of scale deposition could also cause corrosion perforation and large-scale pits.


2012 ◽  
Vol 496 ◽  
pp. 427-430
Author(s):  
Li Dan Chen

By now, it is hard for an effective determination of the engine abnormal sound according to the existing auscultation method based on human experiences and diagnosis aided by instruments. For this reason, the author presented an innovative method that was by the using of atomic absorption spectroscopy technology for a rapid determination of the engine crankshaft bearing abnormal sounds. Major metals contents (Cu and Pb) in 20 batches of Audi A6 engine lubricating oil were detected by atomic absorption spectrometry. Samples were taken from the oil of mileages from 5000km to 69000km and 3000km intervals. Then the databases of main metal contents of different driving miles were built within the same vehicle type. This study showed that the main metal contents were fluctuating with the increasing of driving miles within certain range. For the practical application, we built a connection between engine abnormal sound faults and the major metal contents in the engine lubricating oil. By comparing the metal contents in problem engine with the established contents changing trends chart, we could get a rapid determination about the engine abnormal sound fault without disintegration of the car. To sum up, the achievements of this study helped to reduce vehicle maintenance costs and improved the fault diagnosis accuracy in abnormal sound of engine crankshaft bearing.


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