Journal Bearing Test Research Articles

Fabrication of Cu-Infiltrated Journal Bearing by Binder Jetting Additive Manufacturing

In this study, considering the economic feasibility of products that can be produced through the binder jetting additive manufacturing process, 316L stainless steel, a widely used material with a wide particle size ranging from 15 to 106 μm, was used. The lubrication effect was increased by internal patterning through design for additive manufacturing, and journal bearing parts with excellent load resistance and wear resistance were implemented by using wear-resistant Cu as an infiltration material. In addition, to investigate the amount of Cu infiltrated as a function of porosity, the parts were pre-sintered from 1423 K to 1573 K, and the best performance was obtained when Cu was infiltrated after pre-sintering at 1473 K. As a result of rig testing of Cu-infiltrated journal bearings, mechanical properties were obtained that were more than 50% improved compared to those of mass products.

Bio-based lubricant with additives: tribological performances in hydrodynamic journal bearing

PurposeThe purpose of this paper is to investigate the performance of bio-based lubricants (BBL), namely, palm mid-olein (PMO) enriched with an antioxidant agent, tertiary-butylhydroquinone (TBHQ) and a viscosity improver, ethylene-vinyl acetate (EVA), in journal bearing (JB) applications.Design/methodology/approachSamples of the BBL were prepared by blending it with TBHQ and EVA at various blending ratios. The oxidative stability (OS) and viscosity of the BBL samples were examined using differential scanning calorimetry and a viscometer, respectively. Meanwhile, their performance in JB applications was evaluated through the use of a JB test rig with a 0.5 length-to-diameter ratio at various operating conditions.FindingsIt was found that the combination of PMO + TBHQ + EVA demonstrated a superior oil film pressure and load-carrying capacity, resulting in a reduced friction coefficient and a smaller attitude angle compared to the use of only PMO or VG68. However, it was observed that the addition of TBHQ and EVA to the PMO did not have a significant impact on the minimum oil film thickness.Practical implicationsThe results would be quite useful for researchers generally and designers of bearings in particular.Originality/valueThis study used PMO as the base stock, and its compatibility with TBHQ and EVA was investigated in terms of its OS and viscosity. The performance of this treated BBL was evaluated in a hydrodynamic JB.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2023-0363/

Hydrodynamic lubrication behavior under miscellaneous operational conditions via CGB numerical model

The current study is basically focused on investigating the possible ways to enhance the lubricating oil film performance and hence ship energy efficiency of marine journal bearings in general terms. For the intended purpose, a novel numerical Circumferential Grooved Bearing (CGB) model was developed to assess journal bearing operating conditions based on versatile simulation analyses. Prior to all conducted test trials, the model validation has been confirmed based on the conformity between numerical outcomes and those derived from experimental procedures depending on Universal Journal Bearing Test Rig. CGB performance was evaluated at slow speed variations from 25 rpm up to 125 rpm and different applied loads utilizing the two lubricant oil grades of 5W40 and 0W30. Reducing shaft rotational speed by 80% was found to incur a reduction in the maximum oil film pressure value by 1.17 bar and 0.97 bar for the two aforementioned lubricants respectively. Further, the increase of applied loads from 1079 N up to 1471 N at a constant speed of 75 rpm reduces the maximum oil film pressure ratio by 0.14 and 0.18 for the two oil grades subsequently.

Parametric optimisation on the performance of the journal bearing using Taguchi approach

Hydrodynamic journal bearings are widely used to support high-speed rotating equipment due to their excellent strength and load-bearing capacity. Therefore, bearings are essential mechanical elements to improve the quality of rotating equipment. Bearing performance depends on various factors but pressure and frictional torque plays a vital role in load carrying capacity of bearing. In this present work, both experimental and analytical approach of a typical journal bearing has been carried out to determine the optimal performance of the bearing. Taguchi-based optimisation method has been proposed for journal bearing. Taguchi L27 orthogonal array has been planned to study peak pressure and frictional torque with three input parameters speed, load and viscosity index. The result shows that loading criterion influences much on performance of bearing. The experimental data is obtained from a journal bearing test rig and the analytical data are generated by MINITAB 18. From the experiment, it can be confirmed that speed – 2000 rpm, load – 600 N and viscosity index – 150 are the ideal process parameters for lower peak pressure and less frictional torque.

Experimental comparison of the transition speed of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid

A journal bearing test bench is used to find the transition speed between the hydrodynamic and mixed lubrication regimes for a modified magnetorheological (MR) fluid. It is shown that the transition speed of the bearing can be reduced by applying a local magnetic field near minimum film when it is lubricated with the MR fluid, and that this will only marginally increase friction. The lubricating performance of the MR fluid is compared to that of a reference oil, and all experimental results are compared with a Finite Element model based on the Reynolds equation.

Experimental study on hydro- thermal behavior of journal bearing oil film profile in a slow speed diesel engine

Utilizing universal journal bearing test rig, the performance of a heavy-loaded main journal bearing has been investigated based on tracing operational behavior of oil film temperature and pressure profiles. Test trials were conducted observing the loading program of slow speed diesel engine. Examining the effect of different oil grades, it turned out that oil grade of higher viscosity index enhances journal bearing performance and maintains oil film temperature profile stability at both maximum speeds and heavy loads. Further, medium viscosity grade oil reduces fuel consumption and costs from power production for all operational conditions. Regarding the impact of heavy loads on shaft power performance with medium viscosity oil grade, the differences between optimal and heavy loads get lower as the shaft speed increases. Those were 22 %, 9.7 % and 2.1 % corresponding to the shaft speeds of 43 rpm, 90 rpm and 104 rpm respectively. Additionally, the lower the value of the maximum oil film pressure Pmax difference between optimal and heavy load, the higher the ability of the lubricant to promote performance and provide enhanced operating condition stability. Yet, at part load operating conditions entailing running journal shaft at slow speeds during ship maneuverability, it cannot be considered as the best selection due to the heavy loads often applied in such critical operating conditions. Finally, the test-trial based experimental outcomes can provide useful guidance regarding the proper selection of a lubricant for enhanced performance, cost saving and prolonged journal bearing working life.

Experimental Investigation of Main Journal Bearing Performance in Marine Applications with Heavy Loads at Slow Speeds Utilizing Different Grade Oils

Heavy loads are known to be among the most critical operational factors affecting the behavior of the lubricating oil film within journal bearing related to marine slow speed diesel engines. In light of the fact, a comprehensive investigation was carried out to examine the performance of journal bearing under heavy loads resulting from increased maximum pressure within the combustion chamber. Further, the research test trial procedures have been extended to cover the different speed ranges of 40 rpm, 85 rpm and 105 rpm, as corresponding to the engine loads (40 %, 85% and 100 % respectively), together with the different oil grades of 20W50, 5W40 and 0W30. Universal Journal Bearing Test Rig (UJBTR) was utilized for conducting the experimental test trials due to its capability to contain versatile variations regarding the key operational factors. Experimental test trials basically based on tracing the changes in the oil film pressure distribution and the maximum oil film pressure values, have given insight into the behavior of heavy-loaded journal bearing of diesel engine related to ships. Based all the experimental test trials under optimal and heavy load conditions, oil grade 5W40 was concluded to provide the most optimal operating conditions for all tested speed ranges.

Experimental Investigation of Main Journal Bearing Performance in Marine Applications with Heavy Loads at Slow Speeds Utilizing Different Grade Oils

Heavy loads are known to be among the most critical operational factors affecting the behavior of the lubricating oil film within journal bearing related to marine slow speed diesel engines. In light of the fact, a comprehensive investigation was carried out to examine the performance of journal bearing under heavy loads resulting from increased maximum pressure within the combustion chamber. Further, the research test trial procedures have been extended to cover the different speed ranges of 40 rpm, 85 rpm and 105 rpm, as corresponding to the engine loads (40 %, 85% and 100 % respectively), together with the different oil grades of 20W50, 5W40 and 0W30. Universal Journal Bearing Test Rig (UJBTR) was utilized for conducting the experimental test trials due to its capability to contain versatile variations regarding the key operational factors. Experimental test trials basically based on tracing the changes in the oil film pressure distribution and the maximum oil film pressure values, have given insight into the behavior of heavy-loaded journal bearing of diesel engine related to ships. Based all the experimental test trials under optimal and heavy load conditions, oil grade 5W40 was concluded to provide the most optimal operating conditions for all tested speed ranges. Keywords: Hydrodynamic Lubrication, Pressure Distribution, heavy loads, Slow Speeds, Oil Grades.

Development of a pre-screening-method for the qualification of environmentally acceptable lubricants for stern tube systems—The evaluation of friction efficiency and scuffing capacity

Lubricants for stern tube systems are subject to increasingly stringent requirements in terms of environmental compatibility, as any lubricant leakage leads to contamination of the sea. As a result, interest in environmentally acceptable lubricants (EALs) is increasing. Biodegradable ester lubricants represent a possible alternative to conventional, mineral oil-based lubricants. In addition to environmental compatibility requirements, these ester lubricants must also meet tribological requirements. In this study, suitable tribometers were therefore combined in a pre-screening method to cost-effectively test lubricants for their tribological requirements (friction efficiency, wear protection and scuffing capacity). For this purpose, the contact parameters are transferred from the real conditions in the stern tube system’s journal bearing and from the standardized component tests (FZG for gears and FE8 for rolling bearings) to tribological model tests on a Mini-Traction-Machine (MTM, PCS Instruments). The result of the study is a method for the pre-screening of EALs under the application-related journal bearing and standardized component test conditions, respectively. The results show an influence of the lubricant composition on the friction efficiency in fluid friction as well as the transition point from fluid to mixed friction. Furthermore, an influence of the lubricant composition on the scuffing capacity could be shown. The results of friction efficiency and scuffing capacity confirm also a high reproducibility for those pre-screening tests.

Physics-informed neural networks for the Reynolds equation with cavitation modeling

The Reynolds equation with cavitation modeling describes the pressure and liquid ratio in thin viscous flows and is widely used in the field of hydrodynamic lubrication. This work presents a method solving it with physics-informed neural networks (PINNs). A strategy for the efficient training of the PINNs, involving adaptation and loss balancing, is proposed. By extending its inputs by parameters such as the relative eccentricity of a journal bearing, the PINN solves several problems simultaneously and generalizes well making it reusable. Accurate pressure and liquid ratio predictions for further values of the relative eccentricity are then obtained by just evaluating the PINN taking less than a second. Solutions for a journal bearing test case are compared with finite difference solutions.

Experimental Measurements of Oil Films in a Dynamically Loaded Journal Bearing

This article describes the design of a journal bearing test platform capable of high-accuracy film thickness measurements via ultrasonic transducers permanently embedded in both the bearing and rotating shaft. A bespoke hydraulic loading system with programmable valves allowed the application of dynamic loads with defined loading patterns, including the simulation of loading patterns found in real components such as automotive connecting rod bearings. Tests under a range of rotation speeds, temperatures, and loading profiles allowed the detailed analysis of film thickness response to rapidly changing loads. Unlike conventional methods, the ultrasonic technique offers a noninvasive direct measurement of the shaft–bearing interface, thus enabling the study of phenomena such as squeeze film effects. Measurements were achieved by applying a novel referencing method, referred to as the “snapshot technique”. Via this method, squeeze time was shown to reduce with increasing shaft rotation speed, applied load, and bearing temperature. Results were compared against inductive sensors and numerical techniques and good agreement was observed.

Development and Production of Artificial Test Swarf to Examine Wear Behavior of Running Engine Components—Geometrically Derived Designs

Subtractive manufacturing processes are usually accompanied by the occurrence of tiny flakes and swarf, which later on cause severe wear and damage, especially in moving components such as rolling or sliding bearings, pistons, etc. However, up until now, such detrimental effects have hardly been investigated. One reason is the lack of a definition of a typical design of debris particle. Therefore, the main goal of the project described in this paper was to elaborate a draft that defines standardized test particles. It had to be evaluated whether test particles could be adequately reproduced and whether they would reveal significant damage potential. Taking into account future mass fabrication, Micro Powder Injection Molding (MicroPIM) was chosen as a production method. Five different 3D designs of geometrically defined test particles were developed. The maximum size of each design was 1167 mm in green state; however, all samples shrank in size during sintering. Specially tailored feedstocks containing 42CrMo4 steel powders were used and the related molding, debinding and sintering procedures were developed. All particle geometries and related mold inserts were developed using a commercial software routine for the layout of runner systems, gate locations and ejector positions. The damage potential of the test particles was evaluated based on trials using journal bearing and shift valve test rigs. Although only a moderate degree of damage potential could be ascertained up until now, it can be expected that the artificial swarf will enable standardized wear test procedures to be developed.

Universal journal bearing test rig uncertainty and validation measurement to enhance marine shafting performance

Enhancing the ship power transmission is surely a target sought by all those involved in the marine applications, mainly due to its beneficial results regarding making tangible reduction in fuel oil consumption, consequently considerable reduction in emissions to environment. The oil film lubrication within journal bearings is certainly a key factor in attaining that goal. Besides, journal bearings being essentially intrinsic structures by which numerous experimental tests could successfully be carried out. The first vital step in the uninterrupted series of the research efforts at hand has been to design and construct a journal bearing test rig (JBTR) characterized by sufficient validity for embracing all aspired experiments. Additionally, following the construction of the test rig, there emerged the need to realize the second step which mainly focused on enhancing and promoting the range and capabilities of the journal bearing, which ultimately turned it into a universal journal bearing test rig (UJBTR). Such step has granted the structure the ability to embrace even more sophisticated and much wider range of experiments. Further, one of the main consequences resulting from conducting versatile experiments and tests are the inevitable errors, or rather more precisely the uncertainties. Conducting such essential tests would entail making measurements, which in turn would incur necessary uncertainties. Consequently, there arose the need to introduce the current paper presenting a thorough investigation relating to the uncertainty measurement with view to better identifying the nature of such errors, with view to keeping them to a minimum and trying to overcome their hazardous consequences in as far as the experimentation procedures and outcomes are related.

An Experimental Investigation of Static Properties of Bio-Oils and SAE40 Oil in Journal Bearing Applications.

Considerable research has been conducted in the past decade and a half regarding the bio-lubricants potential to replace mineral-based lubricants as mainstream lubricants such as engine oil, hydraulic oil, compressor oil, and metalworking oil. This study studied several bio-lubricants (rapeseed oil, palm olein, and soybean oil) and a mineral-based lubricant, SAE40. The bio-lubricants have better physiochemical, tribological characteristics and environmental friendly nature, and are promising to replace mineral-based lubricants. In this study, a journal bearing test rig (JBTR) was developed in order to investigate the effect of journal speed on the temperature of oil film with time. Additionally, the load-carrying capacity of bio-oils was tested against the mineral-based lubricant SAE40 by adding a load on the journal. For all three speeds, i.e., 1000, 1500, and 2000 rpm, the bio-lubricants recorded minimum temperature. At 1000 rpm, rapeseed oil recorded a 9.2% lower temperature than SAE40. Similarly, at 2000 rpm, rapeseed oil recorded a minimum temperature that was 2.5% lower than SAE40; in comparison, at 1500 rpm, palm olein recorded a minimum temperature that was 1.8% less than SAE40. Overall, the results of this study revealed that bio-oils recorded a lower temperature rise than mineral oil. These results are very encouraging for further research in this area.

Numerical Study of a Journal Bearing with Scratches: Validation with Literature and Comparison with Experimental Data

The lifespan of journal bearings is directly related to the operating conditions they have to face and reducing their maintenance intervals allows one to have a clear idea about their performance when issues occur. The presence of scratches on one of its surfaces degrades the performance of a journal bearing. These effects have already been assessed in experiments; however, numerical studies on this subject are still scarce. This work develops a numerical thermohydrodynamic (THD) program using the finite volume method to simulate the effects of scratches on the performance of journal bearings. To test the validity of the program, the numerical results are compared with the scientific literature and with experimental measurements conducted using the Pprime Institute journal bearing test rig. Some minor discrepancies are observed, but the overall results are in good agreement.

Experimental analysis of tribological properties of polyisobutylene thickened oil in lubricated contacts

The main objective of this research work is to examine experimentally the tribological performance of polymeric viscosity index improver (VII) in boundary/mixed and hydrodynamic lubricated concentrated contact by simulating non-conformal and conformal geometry in the versatile multispecimen tribotester. Three different experimental approaches (Four ball tester, pin on roller tester and journal bearing test rig) were used to study Polyisobutylene (PIB) as VII. The ability of Polyisobutylene (PIB) blends to reduce friction and wear on the solid/liquid interface has been observed to depend strongly on the polymer concentrations. This study is useful for reducing wear and friction significantly for 15% concentration by weight of PIB blend in paraffinic low viscosity base oil N150. For higher concentration studied, the friction was observed eventually increase giving antagonistic behaviour with base oil.

Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

Experimental analysis of the efficacy of vegetable oil-based nanolubricants for improving journal-bearing performance

The present experimental study explores the performance of Hydrodynamic journal bearings operating with vegetable oil-based nanolubricants. For this study, titanium oxide nanoparticles have been added to canola oil by varying the volume fraction from 0% to 0.04%. An assessment of performance characteristics has been done by using a journal-bearing test rig under different operating conditions. The outcome of the experimental results aimed at the addition of nanoparticles to base lubricants to improve the performance was observed to be favorable. However, under high operating conditions, the influence of nanoparticles is observed to be less useful. The fluid film pressure of nanolubricants increased up to a specific volume concentration of titanium oxide nanoparticles (i.e. 0.02%) beyond which no further enhancement was observed. At a load of 3000 N, the fluid film pressure increased up to 10%, when a bearing is lubricated using canola oil with a 0.02% volume fraction of nanoparticles. The heat transfer rate was found to be higher for nanolubricants in comparison to a base oil and the fluid film temperature was reduced by up to 15% at a volume fraction of 0.04%. Furthermore, rheological studies reveal that the prepared nanolubricants exhibited Newtonian behavior under the given conditions. The percentage increment of viscosity varied from 2.1% to 15.4% and 2.43% to 13.89% for a volume fraction ranging from 0.01% to 0.04% at a temperature of 40 °C and 100 °C, respectively. The dynamic light scattering results confirmed that the particles were well distributed in a base lubricant without much aggregation.

Performance analysis of journal bearing operating on nanolubricants with TiO2, CuO and Al2O3 nanoparticles as lubricant additives

Present experimental study investigate the performance analysis of Journal bearing operating on Nanolubricants prepared by adding TiO2, CuO and Al2O3 nanoparticles as lubricant additives in Avalon ISO Viscosity grade 46 oil. By adding nanoparticles, the viscosity of the lubricant oil is improved, and, in effect, a performance characteristic of journal bearing is enhanced. Nanoparticles used for present work is mixed with base oil with volume fractions of 0.25%, 0.5%, 1% and 2% with the help of mechanical agitator and ultrasonication. Journal bearing Test Rig TR-60 is used to experimentally investigate pressure distribution and load carrying capacity. Performance of bearing is measured at speeds 250 rpm, 500 rpm and at loads 300 N and 450 N. The results indicate a rise in maximum pressure and load carrying capacity of journal bearing by adding TiO2, CuO, and Al2O3 nanoparticles as lubricant additives compared to base oil without nanoparticles additives.

Experimental investigation into the effects of diesel dilution on engine lubrication

The dilution of lubricant due to contamination with diesel fuel is an increasingly prevalent, potentially important and poorly understood issue. This study addresses two fundamental questions: 1) How does the change in lubricant rheology due to diesel dilution affect engine lubrication? 2) How is the chemical performance of lubricant components (base oil and performance additives) impacted by diesel dilution under different lubrication regimes (boundary/full film, hydrodynamic/elastohydrodynamic). This is achieved by testing three lubricant samples: 1) neat fully formulated 0W-30 engine oil, 2) fully formulated 0W-30 oil diluted with diesel at a concentration of 15%, denoted “0W-30D”, and 3) neat, fully-formulated 0W-16, with the same base oil components and performance additives as the 0W-30, but blended to give a viscosity equal to that of the diluted an equivalent “0W-30D”. Tribometer tests, including 1) low pressure, low shear viscosity, 2) Ultra-high Shear Viscosity (USV), 3) elastohydrodynamic film thickness, 4) Stribeck friction and 5) boundary friction and wear, are then conducted. To further emulate engine lubrication conditions, Stribeck curve measurements are performed on the three lubricants using a journal bearing test rig, fitted with a connecting-rod and commercial diesel engine shells. Results suggest that diesel dilution only slightly affects chemical additive performance (with friction modifiers being more inhibited than anti-wear additives) but does reduce both viscosity and film thickness. However, care must be taken in using viscometrics to predict dilution behaviour because 1) the pressure viscosity coefficient is also affected by diesel dilution which has implications for elastohydrodynamically lubrication contacts, 2) shear thinning means that viscosity modifier additives effects lose their functions at high shear rates; whereas diesel contamination affects viscosity behaviour throughout the whole shear rate range.