Numerical Simulation on Velocity Profiles of Mill Bearing Lubrication

2010 ◽  
Vol 145 ◽  
pp. 282-286
Author(s):  
Qing Xue Huang ◽  
Jian Mei Wang ◽  
Yu Gui Li ◽  
Li Feng Ma ◽  
Chun Jiang Zhao
Keyword(s):  
Cross Section ◽  
Velocity Profiles ◽  
Flow State ◽  
Oil Film ◽  
Velocity Gradients ◽  
Oil Flow ◽  
The Mathematical Model ◽  
The Relationship ◽  
General Velocity ◽  
Oil Film Pressure

No 460 oil-film bearing oil as the dedicated lubricant is regarded as the incompressible Newtonian fluid. To comprehensively analyze the real oil flow state, the mathematical model on velocity profiles, together with its dimensionless equations, is established, and the calculating program is developed to simulate the 3D velocity profiles and velocity gradients at different oil flow layers. The relationship between velocity profiles and the oil film pressure is discussed, and the velocity tendency is consistent with the general velocity profile of wedge cross section. The conclusions are beneficial to the further study on lubricating performances of heavy contact components and to prolong their service lives.

Numerical Simulation on Oil-Flow-State of Gap Oil Film in Sector Cavity Multi-Pad Hydrostatic Thrust Bearing

2010 ◽  
Vol 37-38 ◽  
pp. 743-747
Author(s):  
Xiao Dong Yu ◽  
Xiu Li Meng ◽  
Hui Jiang ◽  
Xiao Zhong Lou ◽  
Bo Wu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Critical Speed ◽  
Thrust Bearing ◽  
Lubricating Oil ◽  
Good Effect ◽  
Critical Flow ◽  
Flow State ◽  
Oil Film ◽  
Oil Flow

Hydrostatic thrust bearing lubrication is significantly affected by the oil flow state of gap oil film, but it can not be measured by experiment and analysis. For this problem, the oil flow state of gap oil film in sector cavity multi-pad hydrostatic thrust bearing during rotation was simulated by using computational fluid dynamics, lubricating theory, and Finite Element Method. Laminar model and κ-ε turbulence model were adopted to model incompressible steady equations, and the equations were discreted by using Finite Volume Method and Second-order Finite Difference. By comparing the calculated results of numerical simulation and semi-empirical theoretical equation, the numerical simulation is proved feasible in oil film state analysis parameter prediction, which can overcome the deficiency of single model and get good effect. Streamlines and velocity vectors show that the lubricating oil flow in the resistive oil edges and oil cavities are laminar flow under the conditions of speed and flow in less than a certain value, while the flow and speed are more than a certain value, the lubricating oil flow in the resistive oil edges is also laminar flow, but the lubricating oil flow in the oil cavities is turbulent flow, then determines critical flow and critical speed. The critical flow and critical speed were determined, it provides a theoretical basis of the temperature field and thermal field deformation calculation.

Stability of Jeffcott Rotor Operating in Tilting 3-Pad Journal Bearings with Turbulent Oil Film

2009 ◽  
Vol 147-149 ◽  
pp. 450-455
Author(s):  
Stanislaw Strzelecki ◽  
Sobhy M. Ghoneam
Keyword(s):  
Theoretical Investigation ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Oil Film ◽  
Temperature Distributions ◽  
Jeffcott Rotor ◽  
Oil Flow ◽  
The Stability ◽  
Oil Film Pressure

This paper introduces the results of theoretical investigation on the dynamic characteristics of tilting 3-pad journal bearing that operates with turbulent oil film. The Reynolds, energy, viscosity and geometry equations determine the oil film pressure, temperature distributions, and oil film resultant force that are the grounds for the dynamic characteristics of bearing. These equations were solved simultaneously on the assumption of adiabatic laminar or adiabatic turbulent oil flow in the bearing gap. The stability and system damping of Jeffcott rotor operating in tilting 3-pad journal bearing was determined.

Numerical Simulation and Analysis of Carbon Black in Pneumatic Conveying Pipe

2014 ◽  
Vol 1052 ◽  
pp. 561-566
Author(s):  
Zhi Hua Li ◽  
Yan Qing Yang ◽  
Ya Zhou Yu ◽  
Guang Peng Liu ◽  
Xu Chao Li
Keyword(s):  
Carbon Black ◽  
Cross Section ◽  
Fluid Pressure ◽  
Flow State ◽  
Pneumatic Conveying ◽  
Dense Phase ◽  
Bent Pipe ◽  
The Mathematical Model ◽  
Research And Design ◽  
Conveying System

Based on establishment of the mathematical model about the carbon black dense phase pneumatic conveying, using computational fluid dynamics ( referred to as CFD) methods, this paper stimulated the carbon black flow state inside the bent pipe. Through simulation and analysis, the carbon black particles' flow condition along the bent pipe, the carbon black particles' distribution variation at the bent pipe cross-section, the bent pipe part where worn most easily, the fluid pressure cloud and the optimum R/D have been gotten. All these provide basis for the research and design of carbon black dense phase pneumatic conveying system.

scholarly journals Study on Oil Film Characteristics of Piston-Cylinder Pair of Ultra-High Pressure Axial Piston Pump

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 68 ◽  
Author(s):  
Jin Zhang ◽  
Baolei Liu ◽  
Ruiqi LÜ ◽  
Qifan Yang ◽  
Qimei Dai
Keyword(s):  
High Pressure ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Film Pressure ◽  
Oil Film ◽  
Ultra High Pressure ◽  
Piston Cylinder ◽  
The Mathematical Model ◽  
Axial Piston ◽  
Oil Film Pressure

The piston-cylinder pair is the key friction pairs in the piston pump. Its performance determines the volume efficiency of piston pump. With the increase of load pressure, the leakage at the clearance of piston-cylinder pair will also increase. In order to reduce leakage, the clearance of the piston-cylinder pair of the ultra-high pressure piston pump is smaller than that of the medium-high pressure piston pump. In order to explore whether the piston will stuck in the narrow gap, it is necessary to study the oil film characteristics of the piston-cylinder pair under the condition of ultra-high pressure, so as to provide a theoretical basis for the optimal design of the piston-cylinder pair of ultra-high pressure axial piston pump. In this paper, an ultra-high pressure axial piston pump is taken as the research object, and its structural characteristics are analyzed. The mathematical model of the oil film thickness of the piston-cylinder pair is established by using the cosine theorem in the cross section of the piston. The finite volume method is used to discretize the Reynolds equation of the oil film of the piston-cylinder pair, and the over relaxation iteration method is used to solve the discrete equations, and the mathematical model of the oil film pressure of the piston-cylinder pair is obtained. The mathematical model of oil film thickness and pressure field of piston-cylinder pair is solved by programming. The dynamic change process of oil film thickness and pressure field of the plunger pair of the ultra-high pressure axial piston pump under the load of 20 MPa and 70 MPa is obtained. Under the two conditions, the thinnest area of the oil film reaches 3 μm and 2 μm dangerous area respectively; the oil film pressure reaches 20 MPa and 70 MPa respectively when the swashplate rotates 10° and continues to increase with the increase of swashplate rotation angle. When the rotation angle reaches 90°, the oil film pressure also reaches the maximum value, but there is no pressure spike phenomenon. The oil film pressure characteristics of ultra-high pressure axial piston pump under conventional and ultra-high pressure conditions were obtained by modification and experimentation.

Numerical Modeling of Unsteady Oil Film Motion Characteristics in Bearing Chambers

2015 ◽  
Vol 32 (3) ◽  
Author(s):  
Jingyu Zhao ◽  
Zhenxia Liu ◽  
Yaguo Lu ◽  
Jianping Hu
Keyword(s):  
Film Thickness ◽  
Theoretical Study ◽  
Rotation Speed ◽  
Three Dimensional ◽  
Lubricating Oil ◽  
Flow State ◽  
Oil Film ◽  
Model Based ◽  
Oil Flow ◽  
Motion Characteristics

AbstractTo obtain motion characteristics of the lubricating oil film on the aero-engine bearing chamber wall, a complete mathematical model based on theoretical study to solve three-dimensional unsteady oil film motion was established. On the basis of verifying the rationality of the computational model, the variations of the oil film thickness, velocity and temperature with the rotation speed and lubricating oil flow were analyzed and studied. The numerical results show that the following: In the stable oil film flow state, the oil film thickness shows a decreasing trend with increase in rotation speed and an increasing trend with increase in the lubricating oil flow. Particularly, comparison with the experimental work shows that the proposed numerical model based on theoretical study to solve unsteady oil film motion is a valuable technical means for the study of oil film movement mechanism and the design of actual bearing chamber.

Static Characteristics of Low Speed Cylindrical Journal Bearings of the Rope Wheel of Hoist Tower

2005 ◽  
Author(s):  
S. Strzelecki ◽  
W. Wojcicki ◽  
W. Famulski
Keyword(s):  
Load Capacity ◽  
Journal Bearings ◽  
Static Characteristics ◽  
Rolling Bearings ◽  
Oil Film ◽  
Low Speed ◽  
Oil Flow ◽  
Bearing Design ◽  
Bearing System ◽  
Oil Film Pressure

The design solutions of bearings carrying the shafts of rope wheels on the hoist tower of coal mines consists the rolling bearings or plain journal ones. Plain journal bearings allow for easy assembling and for smooth operation without vibrations. Static characteristics of journal bearings consist of oil film pressure and temperature distributions, static equilibrium position angles, load capacity, oil flow and power loss and their knowledge is the basis of bearing design. The paper comprises the static characteristics of low speed cylindrical journal bearings that are applied in the bearing system of the rope wheels of hoist tower. The calculations of these characteristics were carried-out on the assumption of adiabatic oil film.

scholarly journals An experimental cross-section measurement of 10B(n,α)7Li reaction on counting alpha particles track density

2018 ◽  
Vol 16 (37) ◽  
pp. 108-117
Author(s):  
Khalid R. Flyah
Keyword(s):  
Mathematical Model ◽  
Cross Section ◽  
Chemical Etching ◽  
Track Detector ◽  
Alpha Particles ◽  
Nuclear Track Detector ◽  
Etching Solution ◽  
Section Measurement ◽  
The Mathematical Model ◽  
The Relationship

The present work determines the particle size based only on the number of tracks detected in a cluster created by a hot particle on the CR-39 solid state nuclear track detector and depending on the exposure time. The mathematical model of the cross section developed here gives the relationship between alpha particle emitting from the (n, α) reaction and the number of tracks created and distribution of tracks created on the surface of the track detector. In an experiment performed during this work, disc of boron compound (boric acid or sodium tetraborate) of different weights were prepared and exposed to thermal neutron from the source. Chemical etching is processes of path formation in the detector, during which a suitable etching solution attacks the detector at a sufficient speed and the damaged regions along the ion trails (latent track) are preferentially dissolved, removed and get transformed into a hollow channel. The most common etching for plastics is the aqueous solutions of NaOH and temperatures in between 50˚C - 80˚C.The program (CR-39) processing counting and calculations only take place depending on the number of tracks.

Finite Element Analysis of Static Characteristics of a Hydrostatic Guideway and its Effect Factors

2011 ◽  
Vol 199-200 ◽  
pp. 1339-1342 ◽  
Author(s):  
Ya Zhou Sun ◽  
Yi Lei Liu ◽  
Hai Tao Liu ◽  
Ying Chun Liang
Keyword(s):  
Fe Model ◽  
Static Characteristics ◽  
Static Stiffness ◽  
Element Analysis ◽  
Oil Film ◽  
Ultra Precision ◽  
Precision Machine Tools ◽  
The Relationship ◽  
Clearance Change ◽  
Oil Film Pressure

Guide ways of ultra-precision machine tools always have sufficient stiffness and guiding precision. But guide way rails deformation caused by oil film pressure and slider offset lead to oil film clearance change which affects static stiffness and guiding precision. An inside-slider hydrostatic guide way is designed, and its static characteristics are analyzed. As a result, the effect of slider offset on stiffness and guiding precisions is obtained. A FE model of guide way is established. An elastomer of virtual material properties is used to simulate oil film, so that the relationship between oil film clearance and pressure can be represented in a certain range. Static stiffness and guiding precision are obtained considering deformation of rails.

Drag Reduction and Velocity Profiles Distribution of Crude Oil Flow in Spiral Pipes

2015 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Yanuar Yanuar ◽  
Kurniawan T. Waskito ◽  
Gunawan Gunawan ◽  
Budiarso Budiarso
Keyword(s):  
Drag Reduction ◽  
Crude Oil ◽  
Velocity Profiles ◽  
Oil Flow

Temperature Influence on Performance of Oxidation Ponds

1991 ◽  
Vol 24 (5) ◽  
pp. 85-96 ◽  
Author(s):  
Qingliang Zhao ◽  
Zijie Zhang
Keyword(s):  
Mathematical Model ◽  
Temperature Influence ◽  
Field Scale ◽  
Experiment Data ◽  
Computer Technique ◽  
Oxidation Pond ◽  
Optimum Model ◽  
Oxidation Ponds ◽  
The Mathematical Model ◽  
The Relationship

By means of simulated tests of a laboratory–scale oxidation pond model, the relationship between BOD5 and temperature fluctuation was researched. Mathematical modelling for the pond's performance and K1determination were systematically described. The calculation of T–K1–CeCe/Ci) was complex but the problem was solved by utilizing computer technique in the paper, and the mathematical model which could best simulate experiment data was developed. On the basis of experiment results,the concept of plug–ratio–coefficient is also presented. Finally the optimum model recommended here was verified with the field–scale pond data.

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