scholarly journals Friction and Wear Characteristics of Microporous Interface Filled with Mixed Lubricants of M50 Steel at Different Loads

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2934
Author(s):  
Xiyao Liu ◽  
Zhiwei Lu ◽  
Hao Dong ◽  
Yan Cao ◽  
Xueming Qian
Keyword(s):  
Flow Behavior ◽  
Interfacial Structure ◽  
Laser Additive Manufacturing ◽  
Load Range ◽  
Lubricating Film ◽  
Lubricating Layer ◽  
Lubrication Characteristics ◽  
Worn Surface ◽  
M50 Steel

Improving the tribological performance of M50 steel under the conditions of wide load range is of great significance. In this study, the interfacial structure of surface micropores filled with Sn–Ag–Cu or Sn–Ag–Cu/whisker carbon nanotubes (whiskerCNT) of M50 material was prepared by laser additive manufacturing and high-temperature infiltration. From 2 to 22 N, the lubrication characteristics of Sn–Ag–Cu and whiskerCNT in surface micropores of M50 was investigated. Results indicate that Sn–Ag–Cu can precipitate to the worn surface and form a lubricating layer, which has a good lubricating effect. Moreover, the flow behavior of Sn–Ag–Cu on a worn surface can play the role of crack healing. At higher load, the strength of the lubricating film is enhanced by whiskerCNT, which renders the lubricating film not vulnerable to premature rupture.

scholarly journals A Novel Inward Gradient Self-Lubrication Layer with Soft Alloys and Its Lubricating Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Songshan Yan ◽  
Ling Qin ◽  
Rui Hu ◽  
Zuomin Liu
Keyword(s):  
Gradient Distribution ◽  
Lubricating Film ◽  
Lubricating Layer ◽  
Lubrication Layer ◽  
The Matrix ◽  
Lubricating Property ◽  
Soft Metal ◽  
Worn Surface ◽  
High Frequency Induction ◽  
Lubricating Mechanism

A novel ceramic composite inward gradient distribution layer has been developed. The layer is a lubricating layer in which soft-metal lubricants are compounded into the ceramic matrix by high frequency induction infiltrating method. The design of the layer and its lubricating mechanism are investigated in the paper. The results show that the property of the layer greatly depends on the wetting angle of the soft-metal lubricants on the matrix and the proportion of Ag, Cu, Sn, and Pb as well as the infiltrating parameters. Based on a lot of experiments, a novel inward gradient layer with Pb28Sn19Ag6Cu has been developed. The layer has an excellent lubricating property (friction coefficient about 0.2~0.3 at 600°C). The research reveals the lubricating mechanism, observing the phenomenon that the soft-metal in the matrix diffuses out of the frictional surface, and measures the lubricating film thickness as about 20 μm on the worn surface.

scholarly journals Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 178
Author(s):  
Souhail Maazioui ◽  
Abderrahim Maazouz ◽  
Fayssal Benkhaldoun ◽  
Driss Ouazar ◽  
Khalid Lamnawar
Keyword(s):  
Flow Behavior ◽  
Continuous Phase ◽  
Raw Material ◽  
Rheological Characterization ◽  
Phosphate Ore ◽  
Insoluble Particles ◽  
Experimental Protocols ◽  
Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

Experimental and Numerical Investigations of a Turbulent Flow Behavior in Isolated and Nonisolated Conical Diffusers

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
F. Aloui ◽  
E. Berrich ◽  
D. Pierrat
Keyword(s):  
Turbulent Flow ◽  
Flow Behavior ◽  
Piv Measurements ◽  
Numerical Investigations ◽  
Image Velocimetry ◽  
Sst Model ◽  
Proper Orthogonal ◽  
Hydraulic Circuits

In some industrial processes, and especially in agrofood industries, the cleaning in place mechanism used for hydraulic circuits plays an important role. This process needs a good knowledge of the hydrodynamic flows to determinate the appropriate parameters that assure a good cleaning of these circuits without disassembling them. Generally, different arrangements are present in these hydraulic circuits, such as expansions, diffusers, and elbows. The flow crossing these singularities strongly affects the process of cleaning in place. This work is then a contribution to complete recent studies of “aliments quality security” project to ameliorate the quality of the cleaning in place. It presents experimental and numerical investigations of a confined turbulent flow behavior across a conical diffuser (2α=16 deg). The role of a perturbation caused by the presence of an elbow in the test section, upstream of the progressive enlargement, was studied. The main measurements were the static pressure and the instantaneous velocity fields using the particle image velocimetry (PIV). Post-processing of these PIV measurements were adopted using the Γ2 criterion for the vortices detection and the proper orthogonal decomposition (POD) technique to extract the most energetic modes contained in the turbulent flow and to the turbulent flow filtering. A database has been also constituted and was used to test the validity of the most models of turbulence, and in particular, a variant of the shear stress transport (SST) model.

Tribological Performance of a Non Asbestos Organic Brake Pad Using Various Organic and Mineral Fibers

2012 ◽  
Vol 585 ◽  
pp. 559-563
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan
Keyword(s):  
Wear Behavior ◽  
Testing Machine ◽  
Brake Disc ◽  
Brake Pads ◽  
Degradation Temperature ◽  
Industrial Standards ◽  
Worn Surface ◽  
Acrylic Fibers ◽  
Automotive Brake

Non-Asbestos organic composite friction materials are increasingly used in automotive brake disc pad applications. The present paper deals with the role of various organic fibers Kevlar, Acrylic fibers and the Rock fiber namely the Lapinus fiber on the fade and recovery behavior of friction composites. Three different friction composites were developed with same formulation varying only the percentage of Kevlar, Acrylic and lapinus fibers within the formulation. The formulations containing 13.5% of these fibers were developed as brake pads and designated as NA01, NA02 and NA03 respectively. The chemical and Mechanical properties are tested as per Indian Industrial standards.. The composites are then tested for the tribo-performance using Chase Testing Machine following SAE J661a standards. The fade µ, recovery µ and wear are significantly influenced by the amount and type of fiber combinations. Also the TGA reveals the degradation temperature of these fibers. Composite NA 03 containing Kevlar and lapinus combination is found to have good tribo performance. Worn surface analysis by SEM has proved to be useful in understanding the wear behavior of the composites.

The role of residual char on ash flow behavior, Part 2: Effect of SiO2/Al2O3 on ash fusibility and carbothermal reaction

Fuel ◽  
2019 ◽  
Vol 255 ◽  
pp. 115846 ◽  
Author(s):  
Ji Wang ◽  
Lingxue Kong ◽  
Jin Bai ◽  
Huiling Zhao ◽  
Stefan Guhl ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Ash Fusibility

The role of residual char on ash flow behavior, Part 1: The effect of graphitization degree of residual char on ash fusibility

Fuel ◽  
2018 ◽  
Vol 234 ◽  
pp. 1173-1180 ◽  
Author(s):  
Ji Wang ◽  
Lingxue Kong ◽  
Jin Bai ◽  
Huaizhu Li ◽  
Zongqing Bai ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Graphitization Degree ◽  
Ash Fusibility

Deformation Mechanisms and Solid-Solution Strengthening in Ordered Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
Dennis M. Dimiduk ◽  
Satish Rao
Keyword(s):  
Solid Solution ◽  
Flow Behavior ◽  
Stoichiometric Composition ◽  
Dislocation Core ◽  
Deformation Mechanisms ◽  
Solid Solution Hardening ◽  
Solid Solution Strengthening ◽  
Ordered Alloys ◽  
Solute Hardening

ABSTRACTFundamental to understanding the results of alloy design studies, is the need for understanding the intrinsic role of solutes in a particular compound. For many compounds such an understanding must be built from a systematic exploration of the role of deviations from the stoichiometric composition as well as the role of ternary solute additions on the variation of flow behavior. Within most intermetallic systems the problem is complicated since the fundamental mechanisms of flow are not well established and, in those systems where these mechanisms are known, thermal activation can lead to dislocation-core transformations and changes in the operative slip systems with temperature. In general, flow may be governed by more than one dislocation process at a given temperature and deformation twinning may be a major contributing deformation mechanism. The problem of isolating the mechanisms of solid-solution hardening may, therefore, require treatment as a problem of combined strengthening mechanisms operating in parallel. This paper reviews the key aspects of deformation mechanisms and solute strengthening in intermetallic alloys. Classical elastic theories of solute hardening serve as an origin, from which, the progress made to date in isolating the mechanisms of solute hardening in ordered alloys is discussed.

CFD Comparison of Steady and Unsteady Flow Through a Human Nasal Passage

2009 ◽  
Author(s):  
Brian Savilonis ◽  
Kalen Smith
Keyword(s):  
Unsteady Flow ◽  
Steady Flow ◽  
Flow Behavior ◽  
Flow Dynamics ◽  
Nasal Passage ◽  
Normal Breathing ◽  
Flow Through ◽  
Nasal Flow

Understanding of the transnasal pressure and flow behavior during normal breathing conditions has been a subject of much discussion and research. In particular we are interested in testing the hypothesis of quasi-steady flow as well as the role of turbulence on nasal flow dynamics.

The role of residual char on ash flow behavior, Part 3: Effect of Fe2O3 content on ash fusibility and carbothermal reaction

Fuel ◽  
2020 ◽  
Vol 280 ◽  
pp. 118705
Author(s):  
Ji Wang ◽  
Lingxue Kong ◽  
Jin Bai ◽  
Huiling Zhao ◽  
Kang Xue ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Fe2o3 Content ◽  
Ash Fusibility

scholarly journals Effects of the Interfacial Structure on the Methanol Oxidation on Platinum Single Crystal Electrodes

Surfaces ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 177-192 ◽  
Author(s):  
Mohammad Kamyabi ◽  
Ricardo Martínez-Hincapié ◽  
Juan Feliu ◽  
Enrique Herrero
Keyword(s):  
Single Crystal ◽  
Methanol Oxidation ◽  
Interfacial Structure ◽  
Direct Oxidation ◽  
Adsorbed Species ◽  
Oxidation Of Methanol ◽  
Methanol Solutions ◽  
Platinum Single Crystal ◽  
The Right

Methanol oxidation has been studied on low index platinum single crystal electrodes using methanol solutions with different pH (1–5) in the absence of specific adsorption. The goal is to determine the role of the interfacial structure in the reaction. The comparison between the voltammetric profiles obtained in the presence and absence of methanol indicates that methanol oxidation is only taking place when the surface is partially covered by adsorbed OH. Thus, on the Pt(111) electrode, the onset for the direct oxidation of methanol and the adsorption of OH coincide. In this case, the adsorbed OH species are not a mere spectator, because the obtained results for the reaction order for methanol and the proton concentrations indicate that OH adsorbed species are involved in the reaction mechanism. On the other hand, the dehydrogenation step to yield adsorbed CO on the Pt(100) surface coincides with the onset of OH adsorption on this electrode. It is proposed that adsorbed OH collaborates in the dehydrogenation step during methanol oxidation, facilitating either the adsorption of the methanol in the right configuration or the cleavage of the C—H bond.

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