Oil Sumps Research Articles

Investigation on Influence of Circumferential Velocity and Lubrication Oil Grades on Scuffing and Thermal Efficiency of Gearbox

Lubrication oil grades plays major role in reducing the friction to prevent scuffing in gears. Gears transmit power through rolling/sliding contacts between teeth, which must operate reliably for designed life with reduced friction so that there will be minimum wear. Lubrication of tooth contacts, both as a means of minimizing scuffing and as a means of reducing friction due to sliding, is therefore of crucial importance. The circumferential velocity of high speed gearboxes and oil grades plays major role in thermal efficiency of gearboxes. In gearboxes with oil sumps, churning losses contribute for significant portion of the total power loss. Present empirical approaches for examining the churning losses are often limited to certain constraints and operating conditions. Furthermore, they do not provide any information about the oil distribution in the gearbox. In order to overcome these shortcomings, we investigated a steel mill gearbox failure with analytical tools and simulations with the help of renowned software packages and predicted the thermal behavior of the gearbox as function of oil grade and circumferential velocity, also validated later at application.

Thermal analysis of oil sump and compression unit in a rotary compressor

Thermal analysis of the oil sump and compression unit in a hermetic rotary compressor is important for enhancing its performance and reliability. In this study, the temperature distribution, heat-transfer mechanism, and heat balance of the oil sump and compression unit in a rotary compressor were analyzed using the 3D computational fluid dynamics (CFD) fluid-solid coupled model. Considering the practical characteristics of the rotary compressor, some special treatments are proposed for the simulation model. Instead of using empirical formulations, heat-transfer coefficients in the upside of the main bearing and compressor shell were obtained using the 3D CFD simulation model; the dynamic process in the suction chamber and compression chamber was considered to be static and the oil film in the inner wall of the cylinder, rib effect of the A-frame structure at the bottom of the compressor shell, and friction loss in the side of the sliding vane were considered. The simulation results showed good agreement with experimental results. We expect that these analytical results would be of great use in further understanding the temperature distribution and heat-transfer mechanism of oil sumps and compression units and also provide guidelines for improving the performance and reliability of rotary compressors.

A STUDY OF THE DEMULSIFIER EFFECTIVENESS IN THE PRESENCE OF HYDROCHLORIC ACID

Background Efficient production of oil at the fields located on the third and fourth stages of development is not possible without the use of oilfield chemicals. Using different kinds of chemicals have controversial effects on the properties of oil and produced water, which in turn requires a constant feed amount correction demulsifier. Aims and Objectives Investigation of the effect of hydrochloric acid on the properties of water-oil emulsions (WOE) and the effectiveness of the demulsifier during dehydration. The study of the variation of properties of the oil and aqueous phases WOE associated with changes in the concentration of hydrochloric acid in the production wells. Methods The paper uses the following research methods: microscopy, determination of the degree and rate of oil dehydration, determination of the interfacial tension (IFT) at the interface of the «oil - formation water - hydrochloric acid» phase by the method of a rotating drop. Dispersion of the emulsion was evaluated using a microscope «Altami BIO 2». Studies of the effectiveness of the destruction of WOE in the presence of hydrochloric acid were performed in the conventional method «Bottle Test», which determined the rate of dehydration and the residual water content in the settled oil. Studies of IFT performed according to the method of rotating drops on video tensiometer SVT15N (DataPhysics). Results The results of studies evaluating the effect of hydrochloric acid on the destruction efficiency WOE using microscopic techniques and determination of the degree of dehydration of oil rate, measuring the IFT at the interface «oil - formation water - hydrochloric acid». The results of experimental studies have confirmed the adverse effect of hydrochloric acid on the effectiveness of oil dehydration processes. It is found that with increasing the acid concentration takes place decrease in the average size of the dispersed phase droplets and increasing WOE aggregate stability, which adversely affects the operability condition and intermediate layers of oil sumps. It should be noted that for each value of the hydrochloric acid content of the emulsion optimum flow demulsifier is observed. On the basis of the studies for the selected test object, the dependence of the optimal flow rate of the demulsifier on the content of hydrochloric acid in the WOE was determined.

Oil Degradation in a Diesel Engine with Dual-Loop Lubricating System

ABSTRACT A common lubricating oil sump is used in most modern internal combustion engines for cooling, wear protection, and friction reduction. This requires compromises during base oil and additive selection as a result of differing needs for lubricant performance in engine subsystems. The use of a dual lubricating loop, providing separate oil sumps for the power cylinder and valve train subsystems, was investigated experimentally to determine the effect of system segregation on oil degradation. A small diesel engine was modified, installed in a commercial generator unit, and operated for one oil drain cycle. Oil sampling was tailored to assess base and acid numbers, oxidation, soot concentration, water content, and viscosity changes. The experiment complemented an earlier study that investigated the fuel economy benefits of such a lubricating configuration. These include longer drain intervals for the cylinder head and power cylinder subsystems, improved wear performance for the valve train, and opportunities for alternative material selection during engine design. The experiment demonstrated protection of the valve train subsystem from soot contaminants in the power cylinder. Lower total acid number and oxidation tendency was also observed in the valve train.

Scavenge Flow in a Bearing Chamber With Tangential Sump Off-Take

A tangential sump design is employed in several aero-engines mainly due to its simplicity and compactness. However various problems have prompted investigations of the sump design. An experimental program at Purdue University (Chandra, 2006, “Flows in Turbine Engine Oil Sumps,” Ph.D. thesis, School of Aeronautics and Astronautics, Purdue University and Radocaj, 2001, “Experimental Characterization of a Simple Gas Turbine Engine Sump Geometry,” M.S. thesis, School of Aeronautics and Astronautics, Purdue University) was conducted to investigate the characteristics of a tangential sump design like one used in the AE3007 aero-engine. The research employed a transparent chamber to allow unprecedented view of the flow inside the bearing chamber. It was quickly found that a persistent liquid pooling near the drain entrance of a tangential sump obstructs the outflow to the scavenge pump. The air flow near the drain entrance has been shown to have strong reverse flow, even with, or perhaps due to, substantial over-scavenging. Various modifications were tested with varying degrees of success. The work highlights limitations of a tangential sump design. Based on the lessons learned, a new sump design was proposed. Preliminary test of the new sump design has shown positive results.

Properties of magnesium alloy joints welded by a CO2 laser beam

Because of their specific gravity, magnesium alloys find increasing applications in the automotive industry.1 Safety and travelling comfort requirements, satisfied by the use of steel or aluminium parts, are responsible for the increase in the car weight and, therefore, in increased fuel consumption and consequent environmental pollution.2 Replacement of these materials by magnesium alloys satisfies the two requirements while not changing the car mass. The factor which is responsible for the delay in the acceptance of magnesium alloys in the automotive industry is the lack of investigative work into the development of the methods of the manufacture of alloys which would possess the required microstructure, i.e. free of pores and homogeneous structure. The newly developed manufacturing methods indicated, however, that a significant increase in the use of magnesium alloys by the industry can be expected.3 Consequently, a rather limited usage of these alloys in the 1970s for the manufacture of parts, had been extended in the 1990s to whole systems of, mainly, pressure die-cast components (covers, oil sumps, etc) being produced for a number of car makers.4

Sump bay fever: inhalational fever associated with a biologically contaminated water aerosol.

To investigate the clinical, serological, and environmental features of a work related inhalational fever associated with exposure to an aerosol generated from a biologically contaminated 130,000 gallon water pool in a building used for testing scientific equipment. Cross sectional survey of all exposed subjects (n = 83) by symptom questionnaire, clinical examination, spirometry, and serology for antibody to Pseudomonads, pool water extract, and endotoxin. In symptomatic patients diffusion capacity was measured, and chest radiology was performed if this was abnormal. Serial peak flow was recorded in those subjects with wheeze. Bacterial and fungal air sampling was performed before and during operation of the water pool pump mechanism. Endotoxin was measured in the trapped waters and in the pumps. Serum cotinine was measured as an objective indicator of smoking. Of the 20 symptomatic subjects, fever was most common in those with the highest exposure (chi 2 42.7, P < 0.001) in the sump bay when the water was (torrentially) recirculated by the water pumps. Symptoms occurred late in the working day only on days when the water pumps were used, and were independent of the serum cotinine. Pulmonary function was normal in most subjects (spirometry was normal in 79/83, diffusion capacity was low in five subjects, chest radiology was normal). Peak flow recording did not suggest a work relation. The bacterial content of the aerosol rose from 6 to > 10,000 colony forming units per cubic metre (cfu/m3) (predominantly environmental Pseudomonads) when the pumps were operating. High endotoxin concentrations were measured in the waters and oil sumps in the pumps. Low concentrations of antibody to the organisms isolated were detected (apart from two subjects with high antibody) but there was no relation to exposure or the presence of symptoms and similar antibody was found in the serum samples from a non-exposed population. The fever symptoms settled completely with the simple expedient of changing the water and cleaning the pumps. Given the results of our study, the development of inhalational fever in this unique environment and clearly restricted cohort was closely related to the degree of exposure to contaminated aerosol and mainly occurred in the absence of distinct serological abnormality and independent of cigarette smoking.

On-Site Bioremediation Systems Reduce Crude Oil Contamination

Summary. Oilfield properties frequently have areas where soils contain concentrationsof crude oil. These soils can be either"hazardous wastes" or"designated wastes" under regulatory guidelines. As a result, propertyowners and financial institutions face potential liabilities when oilfieldproperties are transferred to new operators, abandoned, or converted to otheruses.Modern, well-designed soil bioremediation systems are cost-effective ways totreat soils that contain concentrations of crude oil, and these systems caneliminate an owner's subsequent liabilities. A modern on- sitebioremediation system requires significantly less surface area, results inlower operating costs, and provides more effective, expeditious results thantraditional land-farming practices. It also eliminates potential long-termliabilities and is typically more cost-effective than excavation and off-sitedisposal of oilfield soils. Case studies indicate that on-site bioremediationsystems have reduced crude oil contamination in soil to levels acceptable toregulatory agencies in less than 20 weeks (in some cases, less than 10 weeks). Total costs for on-site bioremediation range from $35 to $120/yd3oftreated soil, including excavation, depending on specific siterequirements.Introduction. During normal operation of oilfield properties, crude oil or other materialsfrequently leak or spill onto land surfaces. These degraded soils are commonlyassociated with oil wells, sumps and pits, tank batteries, gathering lines, andpump stations. Crude oil and drilling muds may also be found in these areasand, like the contaminated soil, they may be considered either hazardous wastesor designated wastes under current regulatory guidelines. The regulationspertaining to crude oil vary across the U.S. In California, for example, crudeoil is considered a designated waste and its off-site disposal is subject toregulations. If certain constituents (e.g., benzene) are present insufficiently high concentrations, the soil degraded by crude oil may beconsidered a hazardous wasteand subject to additional regulations. Crude oilsludge in an old sump typically contains oilfield treatment chemicals;therefore, the sludge is considered a hazardous waste.

On-Site Bioremediation Systems Reduce Crude Oil Contamination

Summary Oilfield properties frequently have areas where soils contain concentrationsof crude oil. These soils can be either"hazardous wastes" or"designated wastes" under regulatory guidelines. As a result, propertyowners and financial institutions face potential liabilities when oilfieldproperties are transferred to new operators, abandoned, or converted to otheruses. Modern, well-designed soil bioremediation systems are cost-effective ways totreat soils that contain concentrations of crude oil, and these systems caneliminate an owner's subsequent liabilities. A modern on- sitebioremediation system requires significantly less surface area, results inlower operating costs, and provides more effective, expeditious results thantraditional land-farming practices. It also eliminates potential long-termliabilities and is typically more cost-effective than excavation and off-sitedisposal of oilfield soils. Case studies indicate that on-site bioremediationsystems have reduced crude oil contamination in soil to levels acceptable toregulatory agencies in less than 20 weeks (in some cases, less than 10 weeks). Total costs for on-site bioremediation range from $35 to $120/yd3oftreated soil, including excavation, depending on specific siterequirements. Introduction During normal operation of oilfield properties, crude oil or other materialsfrequently leak or spill onto land surfaces. These degraded soils are commonlyassociated with oil wells, sumps and pits, tank batteries, gathering lines, andpump stations. Crude oil and drilling muds may also be found in these areasand, like the contaminated soil, they may be considered either hazardous wastesor designated wastes under current regulatory guidelines. The regulationspertaining to crude oil vary across the U.S. In California, for example, crudeoil is considered a designated waste and its off-site disposal is subject toregulations. If certain constituents (e.g., benzene) are present insufficiently high concentrations, the soil degraded by crude oil may beconsidered a hazardous wasteand subject to additional regulations. Crude oilsludge in an old sump typically contains oilfield treatment chemicals;therefore, the sludge is considered a hazardous waste.

Operational and Developmental Experience on the U.S. Navy Hydrofoil "High Point"

Developmental trials on the U.S. Navy's first hydrofoil ship have determined operational capabilities arid evaluated a number of problem areas. Takeoff speed is 27 knots at a gross weight of 262,000 Ib. At a cruise speed of 40 knots, 4400 lip are required with propellers turning at 1270 rpm. Accelerations in Sea State 4 of 0.35 g rms, while hullborne at 8 knots, are to be compared with 0.07 g rms while foilborne at full power speed. Ventilation of the forward foil and hull furrowing occurred 2 to 3 times/mm in the occasionally larger short-crested waves, thus indicating a need to lengthen the forward strut to give the craft increased capability in the higher seas. A turning radius of 3000 ft was reduced to 1100 ft by increasing the size of the spade rudder. An unstable cavity at the forward foil-strut juncture, causing a roughness in the ride at high speeds, will be corrected with a fillet pod around this juncture. The original neoprene coating on the foils and struts failed below the waterlirie because of adhesion difficulties. Salt water leaking into the transmission oil sumps was the principle reason for frequent dry dockings, thus limiting foilborrie operation to approximately 2200 miles, to date.

Selection of a Propulsor for a Submersible System

sign and development of ocean-going hydrofoil ships. With the exception of having demonstrated full design capability in rough water, the craft has met or exceeded all of her design goals, including a verification of the concept of the turbinepowered, fully submerged foil ship being routinely operated by the white hat Navy. Sporadic leakage of salt water into the transmission oil sumps has been the principal reason for limited reliability to date. This and other problems evaluated during the test program can be corrected, as presently envisioned, without major alteration of the craft. In contrast, much operational experience and test data have been obtained that commend many of the more gross aspects of the craft design. Seakeeping characteristics while hullborne, takeoff performance foilborne comfort, and safety have been found to be most satisfactory. The high vehicular efficiency of the full-scale craft was accurately predicted by model work done prior to construction of the ship.

DRY LUBRICANTS

THE VERY TITLE of this talk is something which is always quite exciting to an Engineer—that is the thought of completely dry lubrication and the possibility of dispensing with such unpleasant necessitites as grease cups, nipples, oil sumps etc. Unfortunately, films of dry lubricants do have co‐efficients of friction and are therefore subject to wear, so the ideal of “life time lubrication” is still in the far and distant future. However new materials are constantly being discovered and/or developed which offer some technical advantage over the previous best, and as each of these materials comes to light it does mean that there are a few more engineering units that at one time were dependent on grease or fluid film lubrication that may now be dry lubricated. It is really the technical‐cum‐commercial development of dry lubricants that this paper discusses. For many years the use of Lamellar solids was limited to such materials as talcum, mica and graphite, the last being by far the most popular and possibly still the most widely used today. In more recent years, molybdenum disulphide has come very much to the fore, and because of certain technical advantages (which will be discussed later) will probably replace graphite if and when it becomes more economical to produce and if it in turn does not first become replaced by other lubricating solids such as boron nitride, tungsten disulphide and cadmium oxide. Of these “new” names in dry lubrication, tungsten disulphide looks very promising and has been selected as the third dry lubricant to discuss.