Effects of Lubricant Viscosity-Temperature Relationship on the Capacity of Sliding Bearing

2013 ◽  
Vol 365-366 ◽  
pp. 1185-1189
Author(s):  
Xiao Fei Dong ◽  
Bin Lin ◽  
Guan Wei Zhang
Keyword(s):  
Experimental Data ◽  
Bearing Capacity ◽  
High Speed ◽  
Temperature Relationship ◽  
Sliding Bearings ◽  
Maximum Stiffness ◽  
Load Carrying ◽  
Water Based ◽  
Fluent Software ◽  
Lubricant Viscosity

Depending on the experimental data of Water-based lubricant viscosity-temperature relationship, this paper adopts Fluent software to analyze how lubricant viscosity-temperature relationship affects load-carrying properties of hybrid sliding bearings. The results show that lubricants will rise obviously when hybrid sliding bearings are in high speed, which will greatly affect bearing capacity and stiffness of bearings. The maximum stiffness of hybrid sliding bearings appears when the eccentricity is from 0.4 to 0.5. This conclusion is dramatically different from bearing capacity number ignored lubricant viscosity-temperature relationship.

Application of nanofluids on various performance characteristics of hydrodynamic journal bearing—A review

2021 ◽  
pp. 095440892110639
Author(s):  
Suman K Mandal ◽  
Biplab Bhattacharjee ◽  
Nabarun Biswas ◽  
Kishan Choudhuri ◽  
Prasun Chakraborti
Keyword(s):  
Carrying Capacity ◽  
Journal Bearings ◽  
Performance Characteristics ◽  
Load Carrying Capacity ◽  
Sliding Bearings ◽  
Engine Oils ◽  
Load Carrying ◽  
Rolling Elements ◽  
Machine Elements ◽  
Lubricant Viscosity

Bearings are designed to support the loads normally applied to the shaft, while allowing relative movement between two machine elements. Journal or sliding bearings are perhaps the most well-known sorts of hydrodynamic bearings. The journal bearings contain no rolling elements and these bearings’ design and construction are simple, but their operation and theory are complex. Due to this and other advantages, journal bearings are much preferred in engineering applications. Simultaneously, the associated research and development have resulted in reasonable progress and therefore, a thorough review of these is earnestly felt. The static and dynamic characteristics of hydrodynamic journal bearings mainly depend on the lubricant viscosity and other factors such as load, speed, friction, and eccentricity. The review analysis focused on nanofluid lubricated hydrodynamic journal bearings are one of the rare topics of interest among tribologists. The use of a nanofluid as a lubricant is very important as it significantly improves the performance characteristics of the investigated bearing. The aggregation of nanoparticles in lubricants available commercially can cause a sharp increase in pressure drop and significantly improve the lubricant viscosity, which leads to an increase in load-carrying capacity. The tribological properties of various lubricants/base oils can be augmented by nanoparticles containing the lubricant. Studies have shown that compared to other conventional engine oils the load-carrying capacity is increased with nanoparticles containing the lubricant.

Numerical Model Updating Technique for Estimating Load Carrying Capacities of High Speed Railway Bridges

2016 ◽  
Vol 106 (8) ◽  
pp. 490-497
Author(s):  
Dong-Uk PARK ◽  
Jae-Bong KIM ◽  
Nam-Sik KIM ◽  
Sung-Il KIM
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Model Updating ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Load Carrying

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

Effects of vessel baffling on the drawdown of floating solids

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Joanna Karcz ◽  
Beata Mackiewicz
Keyword(s):  
Experimental Data ◽  
Power Consumption ◽  
Strain Gauge ◽  
High Speed ◽  
Vessel Diameter ◽  
Rushton Turbine ◽  
Agitated Vessel ◽  
Dimensionless Equation ◽  
Inner Diameter ◽  
Floating Particles

AbstractThe effects of baffling of an agitated vessel on the production of floating particles suspension are presented in this paper. Critical agitator speed, needed for particles dispersion in a liquid agitated in a vessel of the inner diameter of 0.295 m, was determined. The just drawdown agitator speeds were defined analogously to the Zwietering criterion. Specific agitation energy was calculated from the power consumption experimental data obtained by means of the strain gauge method. The experiments were carried out for twelve configurations of the baffles differing in number, length and their arrangement in the vessels. The following high-speed impellers were used: up- and downpumping six blade pitched blade turbines, Rushton turbine, and propeller. The impeller was located in the vessel in the height equal to two-thirds or one-third of the vessel diameter from the bottom of the vessel. The results were described in the form of a dimensionless equation.

Loss Generation in Transonic Turbine Blading

2017 ◽  
Author(s):  
Penghao Duan ◽  
Choon S. Tan ◽  
Andrew Scribner ◽  
Anthony Malandra
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Mach Number ◽  
High Speed ◽  
Turbine Blades ◽  
Surface Boundary ◽  
Loss Model ◽  
Exit Mach Number ◽  
Loss Characteristic ◽  
Shock Loss

The measured loss characteristic in a high-speed cascade tunnel of two turbine blades of different designs showed distinctly different trend with exit Mach number ranging from 0.8 to 1.4. Assessments using steady RANS computation of the flow in the two turbine blades, complemented with control volume analyses and loss modelling, elucidate why the measured loss characteristic looks the way it is. The loss model categorizes the total loss in terms of boundary layer loss, trailing edge loss and shock loss; it yields results in good agreement with the experimental data as well as steady RANS computed results. Thus RANS is an adequate tool for determining the loss variations with exit isentropic Mach number and the loss model serves as an effective tool to interpret both the computational and experimental data. The measured loss plateau in Blade 1 for exit Mach number of 1 to 1.4 is due to a balance between a decrease of blade surface boundary layer loss and an increase in the attendant shock loss with Mach number; this plateau is absent in Blade 2 due to a greater rate in shock loss increase than the corresponding decrease in boundary layer loss. For exit Mach number from 0.85 to 1, the higher loss associated with shock system in Blade 1 is due to the larger divergent angle downstream of the throat than that in Blade 2. However when exit Mach number is between 1.00 and 1.30, Blade 2 has higher shock loss. For exit Mach number above around 1.4, the shock loss for the two blades is similar as the flow downstream of the throat is completely supersonic. In the transonic to supersonic flow regime, the turbine design can be tailored to yield a shock pattern the loss of which can be mitigated in near equal amount of that from the boundary layer with increasing exit Mach number, hence yielding a loss plateau in transonic-supersonic regime.

Study on Performance Optimization of Car Diesel Engine with VNT Based on One-Dimensional Simulation and Experimental Verification

2012 ◽  
Vol 155-156 ◽  
pp. 12-17 ◽  
Author(s):  
Lian Xu Wang ◽  
Da Wei Qu ◽  
Chang Qing Song ◽  
Ye Tian
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Performance Optimization ◽  
High Speed ◽  
Turbine Blades ◽  
Simulation Software ◽  
Engine Operation ◽  
One Dimensional ◽  
Distribution Phase ◽  
Dimensional Simulation

To research the performance optimization of high speed car diesel engine，firstly according to the characteristic of car diesel engine with Variable Nozzle Turbocharger (VNT)， one-dimensional cycle model of the engine was established by using simulation software BOOST and validated by experimental data in this paper. The turbine blades’ opening corresponding to different speed was determined. Therefore the problem that the VNT surges at low engine speed and the inlet air flow is insufficient at high speed was solved. Based on the above model, this paper improved the efficiency of the engine by optimizing the compression ratio and the distribution phase of camshaft and then used the experimental data to check the simulation results. Meanwhile the fuel consumption and the possibility of the engine operation roughness decreased.

Research of the Load Bearing Capacity of Shape-Optimized Metal Inserts Embedded in CFRP under Different Types of Stresses

2017 ◽  
Vol 742 ◽  
pp. 636-643 ◽  
Author(s):  
Florentin Pottmeyer ◽  
Markus Muth ◽  
Kay André Weidenmann
Keyword(s):  
Bearing Capacity ◽  
Residual Strength ◽  
High Speed ◽  
Systematic Research ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Temperature Cycles ◽  
Pull Out ◽  
Different Types ◽  
Impact Energies

An efficient implementation of lightweight design is the use of continuous carbon fiber reinforced plastics (CFRP) due to their outstanding specific mechanical properties. Embedded metal elements, so-called inserts, can be used to join metal-based attachments to structural CFRP parts in the context of multi-material design. They differ from other mechanical fasteners and have distinctive benefits. In particular, drilling of the components to be joined can be avoided and, depending on the preforming, fiber continuity can be maintained using such elements. Thus, no local bearing stress is anticipated. Previous work published by the authors [1] dealt with a systematic research of the influence of different types of stresses on the load bearing capacity of welded inserts. This contribution aims at the investigation of the performance of shape-optimized inserts under the same types of loading to compare with the results of the welded inserts serving as a reference. For that purpose, the respective load bearing capacities were evaluated after preinduced damages from impact tests and thermal cycling. In addition, dynamic high-speed tensile tests (pull-out) were conducted under different loading velocities. It is shown that the load bearing capacities increased up to 19% for high velocities (250 mm/s) in comparison to quasi-static loading conditions (1.5 mm/min) showing an obvious strain rate dependency of the CFRP. Quasi-static residual strength measurements under tensile loading identified the influence of the respective preinduced damages of the insert. Influence of the thermal loading condition was evaluated by placing the specimens in a climate chamber and exposing it to various numbers of temperature cycles from-40 °C to +80 °C with a duration time of 1.5 hours each. Here, it turned out that already 10 temperature cycles decreased the quasi-static load bearing capacity up to 31%. According to DIN EN 6038 the specimens were loaded with different impact energies and the residual strength were measured carrying out pull-out tests. It could be shown that the damage tolerance is significantly lower for the shape-optimized insert due to failure-critical delamination. The optimized insert also endured lower impact energies and the influence on the performance was higher.

Study on Mathematical Model of High Speed Milling Force for Plastic Mold Steel 3Cr2Mo

2011 ◽  
Vol 291-294 ◽  
pp. 710-714
Author(s):  
Jun Min Xiao ◽  
Ying Xu
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
High Speed ◽  
High Hardness ◽  
Milling Force ◽  
High Speed Milling ◽  
Engineering Requirement ◽  
Practical Engineering ◽  
Cad Cam ◽  
Plastic Mold

Mold steel 3Cr2Mo has been used widely in manufacturing of plastic mold formed parts, owing to fine mechanical properties. However, it is also very difficult to cut mold formed parts of steel 3Cr2Mo due to high hardness. Ordinary NC cutting method of steel 3Cr2Mo is unable to relate to modern mold manufacturing due to bad cutting property, so it is extremely significant for improving cutting property of steel 3Cr2Mo to study the high speed milling technology. On the basis of improving the traditional cutting force formula, the mathematical model of high speed milling force for steel 3Cr2Mo was derived and solved by using the experimental data and constructing matrix equation based on MATLAB software. Comparing with experimental data, the error of mathematical model of high speed milling force could be controlled within 6 percent. Due to high precision the model of high speed milling force can meet practical engineering requirement and has great value in the fields of CAD/CAM/CAE.

scholarly journals Kinematic parameters of goats walking on different slopes and biomimetic walking mechanisms

2017 ◽  
Author(s):  
Fu Zhang ◽  
Yafei Wang ◽  
Wei Wang ◽  
Keyword(s):  
Experimental Data ◽  
Theoretical Basis ◽  
High Speed ◽  
Rate Of Change ◽  
Kinematic Parameters ◽  
High Speed Video ◽  
Experimental Image ◽  
Displacement Speed ◽  
Walking Mechanism ◽  
Uphill Walking

A comparative analysis of the kinematic parameters of a goat on different slopes was conducted to study the kinematic parameters of goats on different slopes with walking mechanics. The uphill walking processes on different slopes (0°, 5°, 10°, 15°, 20°, 25° and 30°) were recorded by a high speed video system (VRI Phantom M110). The experimental image results were processed and analyzed using PCC and MATLAB software. The kinematic parameters were obtained from the goat walking on different slopes; these parameters are the changes of centroid with displacement, speed with time, and acceleration with time. As the gradient in the uphill process increases, the range of centroid fluctuation ranges from 0.079 to 0.59 and the rate of change ranges from 0.4 to 2.2 m/s, while the acceleration of the goat slope decreases. The present research can provide theoretical basis and experimental data for the design of a biomimetic agricultural slope walking mechanism.

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