Research on Welding Cracks Prevention in the Fuel-Lubricating Oil Heat Exchanger of Aeroengine

2011 ◽  
Vol 308-310 ◽  
pp. 1156-1161
Author(s):  
Kun Yu Yang ◽  
Xiao Jun Xu ◽  
Hong Yi Qu ◽  
Rui Lin Lai
Keyword(s):  
Heat Exchanger ◽  
Prevention Program ◽  
Shock Absorber ◽  
Oil Spills ◽  
Fuel Oil ◽  
Lubricating Oil ◽  
Flight Safety ◽  
Engine Fuel ◽  
Aero Engine ◽  
Two Measures

Cracks were occurred in welding lines at An Aero engine fuel - oil heat exchanger and oil spills were caused. But shortly, after welding cracks, cracks emerged again and severely threat to flight safety. To improve the overall damping by using new developed shock absorber, and alter the distribution and peak of stress at dangerous parts to prevent cracks by using a prevention program which consisting of two measures: vibration damping and partial damping treatment at the cracks particle which are prone to dangerous parts, were proposed in this paper and for analyze the damping effect, vibration test and compared were used. The results show that the prevention program can effect reduce the peak of stress at the risk of cracks particle which are prone to dangerous parts, and it is certain significant for how to repair and prevent the weld cracks at fuel - oil heat exchanger.

Influence of waste of lubricating oil on the intensity of its aging in a marine trunk diesel engine

2021 ◽  
pp. 56-65
Author(s):  
М.И. Тарасов ◽  
Г.П. Кича ◽  
А.В. Надежкин
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engines ◽  
Fuel Oil ◽  
Engine Oil ◽  
Lubricating Oil ◽  
Engine Fuel ◽  
Operating Life ◽  
Resource Saving ◽  
Aging Model ◽  
Operating Modes

Представлены результаты моделирования старения моторного масла в судовом тронковом дизеле при разном его угаре с идентификацией влияния на степень окисления, срабатывание присадок (по щелочности), накопление нерастворимых продуктов, рост кислотности и смолообразования форсировки двигателя и качества применяемых горюче-смазочных материалов. Показана рациональность исследования процесса старения смазочного масла в циркуляционной системе смазки одноцилиндрового отсека дизеля в лабораторных условиях, что позволяет выдерживать контролируемые параметры комплекса «дизель – топливо – масло» (ДТМ) и снизить затраты на моторные испытания. По результатам расчетно-эксперементального исследования получена модель старения смазочного масла по удельным, приходящимся на единицу мощности двигателя показателям, которая позволяет прогнозировать его состояние в зависимости от срока службы и своевременно отбраковывать. Показана адекватность модели старения по экспериментальным данным использования моторного масла в судовом полноразмерном тронковом дизеле повышенной форсировки. Разработанная модель по указанным направлениям старения позволяет определить состав и режимы функционирования комплекса ДТМ, при которых обеспечивается ресурсосберегающее маслоиспользование в двигателях внутреннего сгорания. This paper presents the results of an engine oil aging model in a marine trunk diesel engine under different combustion conditions with characterization of the effect on the oxidation rate, the actuation of additives (by alkalinity), the accumulation of non-soluble products, an increase in acidity and gumming of the engine boost and the quality of the utilized fuels and lubricants. The efficiency of the lubricating oil aging process study in the circulating lubrication system of a single-cylinder diesel compartment in laboratory conditions is also shown in the article, this allows to maintain the controlled parameters of the «diesel – fuel – oil» system and to reduce the cost of motor tests. Based on the results of a computational-experimental study a lubricating oil aging model was obtained in terms of specific indicators per unit of engine power, which allows to predict its condition depending on the operating life and to promptly discard it. The adequacy of the aging model is based on experimental data of the engine oil use in a ship's full-size trunk diesel engine with increased boost. The developed model of the indicated directions of aging makes it possible to determine the composition and operating modes of the «engine-fuel-oil» system, which ensures resource-saving oil use in internal combustion engines.

Wear Assessment in a Biodiesel Fueled Compression Ignition Engine

2003 ◽  
Vol 125 (3) ◽  
pp. 820-826 ◽  
Author(s):  
A. K. Agarwal ◽  
J. Bijwe ◽  
L. M. Das
Keyword(s):  
Coefficient Of Friction ◽  
Linseed Oil ◽  
Diesel Oil ◽  
Lubricating Oil ◽  
Engine Fuel ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Metal Debris ◽  
Wear Rates ◽  
Biodiesel Blend

Biodiesel is prepared using linseed oil and methanol by the process of transesterification. Use of linseed oil methyl ester (LOME) in a compression ignition engine was found to develop a highly compatible engine-fuel system with low emission characteristics. Two similar engines were operated using optimum biodiesel blend and mineral diesel oil, respectively. These were subjected to long-term endurance tests. Lubricating oil samples drawn from both engines after a fixed interval were subjected to elemental analysis. Quantification of various metal debris concentrations was done by atomic absorption spectroscopy (AAS). Wear metals were found to be about 30% lower for a biodiesel-operated engine system. Lubricating oil samples were also subjected to ferrography indicating lower wear debris concentrations for a biodiesel-operated engine. The additional lubricating property of LOME present in the fuel resulted in lower wear and improved life of moving components in a biodiesel-fuelled engine. However, this needed experimental verification and quantification. A series of experiments were thus conducted to compare the lubricity of various concentrations of LOME in biodiesel blends. Long duration tests were conducted using reciprocating motion in an SRV optimol wear tester to evaluate the coefficient of friction, specific wear rates, etc. The extent of damage, coefficient of friction, and specific wear rates decreased with increase in the percentage of LOME in the biodiesel blend. Scanning electron microscopy was conducted on the surfaces exposed to wear. The disk and pin using 20% biodiesel blend as the lubricating oil showed lesser damage compared to the one subjected to diesel oil as the lubricating fluid, confirming additional lubricity of biodiesel.

Investigation of Heat Transfer for Shell-Tube Fuel-Cooled Heat Exchanger

2013 ◽  
Vol 378 ◽  
pp. 459-465
Author(s):  
Ya Guo Lu ◽  
Peng Fei Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Relative Error ◽  
Absolute Error ◽  
Heat Transfer Characteristics ◽  
Shell Side ◽  
Transfer Characteristics ◽  
Aero Engine ◽  
The Absolute

A calculate method based on ε-NTU model for heat transfer characteristics of shell-tube fuel-cooled heat exchanger of aero-engine lubrication system was built. The heat convection coefficient was obtained by a dimensionless curve (Re~StPr2/3), which was detailed introduced as well. A case study was executed at last. The absolute error of the outlet lubrication of the tube side and the shell side between the value of calculation and experiment was less than ±10°C, and the relative error was less than 6.5%. The absolute error of the heat transferred between calculation and experiment was less than ±0.9kW, and the relative error was less than 7.4%. It indicates that the mothod is available for the investigation of heat transfer characteristics of shell-tube fuel-cooled heat exchanger.

Faults Detection Logic Updating of Fuel Metering Valve on Aero-Engine

2012 ◽  
Vol 503-504 ◽  
pp. 1660-1663 ◽  
Author(s):  
Liang Zhong Ao
Keyword(s):  
Flight Safety ◽  
Control Software ◽  
Fuel Flow ◽  
Flow Metering ◽  
Aero Engine

The basic faults detection logic of fuel flow metering valve can not detect all the faults. It may cause un-commanded in-flight shut-down (IFSD) on the aero-engine and threat the flight safety. The operation principle of fuel flow metering valve is introduced in this paper. The basic faults detection logic is given. Two IFSD examples are presented. To reduce the un-commanded IFSD, faults detection logic updating is discussed. It can be used to design the new control software of the aero-engine and improve the aero-engine’s reliability.

scholarly journals Effect of long term natural weathering on oil composition: study of the 41-years-old Amoco Cadiz and 20-years-old Erika oil spills

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Ronan Jézéquel ◽  
Julien Guyomarch ◽  
Justine Receveur ◽  
Stéphane Le Floch
Keyword(s):  
Methylene Chloride ◽  
Oil Spills ◽  
Weather Conditions ◽  
Fuel Oil ◽  
Terrestrial Vegetation ◽  
Oil Composition ◽  
Heavy Fuel Oil ◽  
Steering Mechanism ◽  
Weathered Oil ◽  
Specific Degradation

On 16 March 1978, the oil tanker the Amoco Cadiz, transporting 223,000 tons of crude oil and 4,000 tons of bunker fuel oil, suffered a failure of her steering mechanism and ran aground on Portsall Rocks, on the Breton coast. The entire cargo spilled out as the breakers split the vessel in two, progressively polluting 360 km of French shoreline from Brest to Saint Brieuc. This was the largest oil spill caused by a tanker grounding ever recorded in the world. The consequences of this accident were significant, and it caused the French Government to revise its oil response plan (the Polmar Plan), to acquire equipment stocks (Polmar stockpiles), to impose traffic lanes in the Channel and to create Cedre. On 12 December 1999, the tanker Erika broke up and sank off the coast of Brittany (France) leading to the spill of 20,000 tons of a heavy fuel oil. 400 km of the French Atlantic coastline were polluted. Because of the characteristics of the oil (a very heavy fuel oil with a high content of light cracking oil) and the severe weather conditions (a centennial storm with spring tides) when the oil came on shore, the Erika spill was one of the most severe accidental releases of oil along the French coastlines. All types of habitat were concerned, and pollution reached the supratidal zone affecting terrestrial vegetation and lichens. In 2019, respectively 41 years and 20 years after these major oil spills affecting the French shoreline, a sampling round was conducted at two sites recorded to present some residual traces of oil. Samples of weathered oil were collected, extracted with methylene chloride and then purified through an alumina-silica microcolumn. SARA fractionation and GC-MS analyses were performed in order to assess respectively the total degradation of the weathered oil (amount of saturates, aromatics and polar fraction) and the specific degradation of nalkanes from n-C9 to n-C40, biomarkers (such as terpanes, hopanes and steranes) and PAHs (parents and alkylated derivatives).

scholarly journals The beneficial effect of oxidation on the lubricating properties of oil

1933 ◽  
Vol 139 (838) ◽  
pp. 447-459 ◽  
Keyword(s):  
Boundary Conditions ◽  
Journal Bearing ◽  
Lubricating Oil ◽  
Engine Fuel ◽  
Experimental Conditions ◽  
Oil Film ◽  
Mineral Oils ◽  
Continuous Rotation ◽  
Made In ◽  
Lubricating Properties

Journal bearing friction experiments have been made generally at relatively low temperatures and otherwise in conditions tending to prevent oxidation of the lubricating oil. Thus Beauchamp Tower’s experiments led Reynolds to the conclusion that fluid friction alone prevails in an oil film maintained by continuous rotation of the journal and that boundary conditions do not become sensible. The more recent experiments by Stanton, undertaken after the Physical Society discussion of 1919, were made to verify the conclusion, and confirmed that especially for mineral oils, “the conditions were in all cases those of perfect lubrication ( i. e ., complete fluid lubrication), no approximation to the hypothetical ones of boundary lubrication being observed,” “the conditions of lubrication of a cylindrical journal being of the Reynolds’ type right up to the seizing pressure. Stanton’s experimental conditions were such that oxidation effects were not obtained. The feed to the journal bearing was always by fresh, not circulated, oil and the temperature of the oil film was maintained at 51·6° C., i. e ., at least 50° lower than required to induce oxidation in a mineral oil particularly susceptible to the effect. The possibility that oxidation might lead to boundary conditions becoming a factor in the measurements was not considered. Oxidation of the oil used to lubricate internalcombustion engines cannot be avoided in the usual conditions of operation, and an investigation of the effect on lubricating value was begun, in connection with experiments made in association with Professor Callendar, on the oxidation of the lighter oils used as engine fuel. The results of lubrication experiments made directly on engines were difficult to interpret. The friction measured is mainly that due to the reciprocating motion of the pistons in the cylinders and oxidation being uncontrolled, the resulting accumulation of semisolid products leads to secondary friction effects greater in magnitude than the primary effect attributable to the fluid alone. The conditions of journal bearing lubrication, on the other hand, can be controlled and friction measured with fair accuracy and it appeared therefore that the investigation could be continued most effectively by using journal bearing testing machines. Machines adapted to be run at the relatively high temperature required for the oxidation of mineral oils had been designed at the N. P. L. by Mr. C. Jakeman in association with whom the experiments were continued, by permission of the authorities concerned.

Controversies in Aquatic Sciences

2014 ◽  
Author(s):  
Judith S. Weis
Keyword(s):  
Oil Spills ◽  
Harmful Effect ◽  
Critical Issue ◽  
Water Soluble ◽  
Fuel Oil ◽  
Scientific Debate ◽  
Scientific Controversies ◽  
Shoreline Protection ◽  
Chemical Companies ◽  
Aquatic Sciences

The aquatic sciences have their share of scientific controversies. In some cases the controversy is the classic situation of economic benefit versus environmental protection; in other cases it involves “genuine” scientific debate over uncertainties of the science or debate over what management option is optimal. This chapter discusses two pollution cases that pit scientists from universities or government agencies against those supported by the industry responsible for the pollution. Additional controversies that are also discussed are a disagreement over management options for shoreline protection, and a scientific disagreement over uncertainties in data on fish populations, which is usually the reason for controversies over fisheries. Controversies over effects of pollution often focus on how much (what concentration) of a chemical is needed to produce a certain harmful effect. Chemical companies tend to argue that levels of a chemical found in the environment are too low to cause problems, while environmentalists typically contend that lower levels can be harmful. One chemical about which there is sometimes controversy is oil. In the case of oil spills, debate commonly centers on how long the effects of pollution last. Oil degrades over time, resulting in less oil in the environment. The critical issue here is: When does this degradation reach a point where spilled oil is no longer harmful? Oil is a complex combination of various hydrocarbons that generally floats on water, although some lighter-weight components (the water-soluble fraction) dissolve. Weathering is a process that takes place in the air and water, in which the lightweight components evaporate, thus leaving the heavier components (e.g., tar), which have traditionally been viewed as less toxic. When oil comes into shallow water and marshes, it can coat and smother resident communities. It can sink below the surface of beaches and marshes and remain there for many years. Oil in marsh sediments undergoes some microbial breakdown but very slowly. Effects of a small oil spill (190,000 gallons of number 2 fuel oil) in Falmouth, Massachusetts, in the late 1960s lasted for over a decade, according to Sanders et al. (1980).

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