Solution for the Pressure and Temperature in Thrust Bearings Operating in the Thermohydrodynamic Turbulent Regime

1974 ◽  
Vol 96 (1) ◽  
pp. 58-68 ◽  
Author(s):  
K. H. Huebner
Keyword(s):  
Thermal Effects ◽  
Eddy Viscosity ◽  
Turbulent Transport ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Turbulent Regime ◽  
Reynolds Analogy ◽  
Thrust Bearings ◽  
Law Of The Wall ◽  
Lubricant Viscosity

A numerical solution is developed for the equations governing the turbulent thermohydrodynamic flow in a sector shaped thrust bearing. The lubricant viscosity is taken as a function of the three-dimensional temperature distribution in the fluid-film. Three-dimensional heat transfer between the lubricant and both the moving and stationary solids is included in the analysis. Isotropy of the turbulent mixing process is assumed. The “law of the wall” for turbulent shear flows is used to define an eddy viscosity based on the local wall shear stress and the viscosity within the film. A modified Reynolds analogy is assumed to relate the turbulent transport of heat and momentum. According to the Ng-Pan theory the momentum transport equations are linearized by assuming the nonplanar flow is a small perturbation of turbulent Couette flow. Thermal effects are shown to be less pronounced in turbulent flow than in laminar flow.

A Three-Dimensional Analysis of Thermohydrodynamic Performance of Sector-Shaped, Tilting-Pad Thrust Bearings

1983 ◽  
Vol 105 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Kyung Woong Kim ◽  
Masato Tanaka ◽  
Yukio Hori
Keyword(s):  
Dimensional Analysis ◽  
Environmental Conditions ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Dimensional Variation ◽  
Lubricant Viscosity

The thermohydrodynamic performance of the bearing is analyzed, taking into account the three-dimensional variation of lubricant viscosity and density. The effect of pivot position and operating and environmental conditions on the performance is studied. The present analysis is compared with the isoviscous or the two-dimensional analysis, and is found to predict the bearing performance more accurately.

A three-dimensional law of the wall for turbulent shear flows

1975 ◽  
Vol 70 (1) ◽  
pp. 149-160 ◽  
Author(s):  
B. Van Den Berg
Keyword(s):  
Experimental Data ◽  
Pressure Gradient ◽  
Velocity Vector ◽  
Shear Flows ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Inertial Forces ◽  
Flow Angle ◽  
Law Of The Wall ◽  
Good Agreement

An extended law of the wall is derived for three-dimensional flows. It describes the variation of the magnitude and direction of velocity close to the wall. The effects of both the pressure gradient and the inertial forces have been taken into account. The derived wall law is valid only when the deviations from the simple law of the wall are not large. The most important feature of a three-dimensional wall law is the prediction of the rotation of the velocity vector near the wall. Comparison of the flow angle variations predicted by the present wall law with the few available experimental data shows good agreement.

Computational Fluid Dynamics Study of Separated Flow Over a Three-Dimensional Axisymmetric Hill

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Varun Chitta ◽  
Tausif Jamal ◽  
D. Keith Walters
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Separated Flow ◽  
Turbulent Shear ◽  
Turbulent Regime ◽  
Flow Transition ◽  
Mean Flow ◽  
Streamline Curvature

This paper investigates the ability of computational fluid dynamics (CFD) simulations to accurately predict the turbulent flow separating from a three-dimensional (3D) axisymmetric hill using a recently developed four-equation eddy-viscosity model (EVM). The four-equation model, denoted as k–kL–ω–v2, was developed to demonstrate physically accurate responses to flow transition, streamline curvature, and system rotation effects. The model was previously tested on several two-dimensional cases with results showing improvement in predictions when compared to other popularly available EVMs. In this paper, we present a more complex 3D application of the model. The test case is turbulent boundary layer flow with thickness δ over a hill of height 2δ mounted in an enclosed channel. The flow Reynolds number based on the hill height (ReH) is 1.3 × 105. For validation purposes, CFD simulation results obtained using the k–kL–ω–v2 model are compared with two other Reynolds-averaged Navier–Stokes (RANS) models (fully turbulent shear stress transport k–ω and transition-sensitive k–kL–ω) and with experimental data. Results obtained from the simulations in terms of mean flow statistics, pressure distribution, and turbulence characteristics are presented and discussed in detail. The results indicate that both the complex physics of flow transition and streamline curvature should be taken into account to significantly improve RANS-based CFD predictions for applications involving blunt or curved bodies in a low Re turbulent regime.

Analysis of Thrust Bearings Operating in Turbulent Regime

1988 ◽  
Vol 110 (3) ◽  
pp. 555-560 ◽  
Author(s):  
M. Harada ◽  
H. Aoki
Keyword(s):  
Steady State ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Cross Coupling ◽  
Fluid Film ◽  
Turbulent Regime ◽  
Pressure Gradients ◽  
Mixing Length ◽  
Thrust Bearings ◽  
Mixing Length Theory

This paper relates to the turbulent motion in the lubricant fluid film with centrifugal effects and the lubrication theory for thrust bearings operating in turbulent regime. Using Prandtl’s mixing-length theory, three-dimensional turbulent velocity distributions, including pressure gradients and centrifugal effects, are calculated, and the cross-coupling of nonplanar flow of the lubricant fluid film is discussed. From these results, turbulent lubrication equations with centrifugal effects are derived. Applying these lubrication equations to a sectorial inclined thrust bearing, the steady-state characteristics and the dynamic ones are calculated.

Measurements in a three-dimensional turbulent boundary layer induced by a swept, forward-facing step

1970 ◽  
Vol 42 (4) ◽  
pp. 823-844 ◽  
Author(s):  
James P. Johnston
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Eddy Viscosity ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Shear Stresses ◽  
Stress Vector ◽  
Mean Velocity ◽  
Vector Direction ◽  
The Mean

An experiment is reported, in which turbulent shear-stresses as well as mean velocities have been measured in a three-dimensional turbulent boundary layer approaching separation. It is shown that even very close to the wall the stress vector does not align itself with the mean velocity gradient vector, as would be required by a scalar ‘eddy viscosity’ or ‘mixing length’ type assumption. The calculation method of Bradshaw (1969) is tested against the data, and found to give good results, except for the prediction of shear-stress vector direction.

Analysis of Bearings Operating in Turbulent Regime

1962 ◽  
Vol 84 (1) ◽  
pp. 139-151 ◽  
Author(s):  
V. N. Constantinescu
Keyword(s):  
Three Dimensional ◽  
Lubricant Layer ◽  
Turbulent Regime ◽  
Mixing Length ◽  
Thrust Bearings ◽  
Mixing Length Theory

Proceeding from the results obtained previously [5] this paper analyzes theoretically the three-dimensional motion in the lubricant layer by using Prandtl’s mixing length theory. Formulas and diagram are presented for calculating journal and thrust bearings subjected to turbulent lubrication.

An Investigation of “Diaphragm” Type Thrust Bearings—Part II: Theory

1975 ◽  
Vol 97 (4) ◽  
pp. 577-584 ◽  
Author(s):  
A. K. Tieu
Keyword(s):  
Thermal Effects ◽  
Three Dimensional ◽  
Finite Width ◽  
Oil Film ◽  
Thrust Bearings ◽  
Temperature Boundary ◽  
Tilting Pad ◽  
Load Carrying ◽  
Theory And Experiment ◽  
Good Agreement

The three types of finite width thrust bearings, tilting pad, diaphragm tilting pad and diaphragm stepped pad, are simulated on the PDP-6 computer taking into account thermal effects on the oil film viscosity and the diaphragm deflection. The temperature boundary conditions of the three-dimensional oil film volume are obtained from the experiment described in Part I. The computed load carrying capacities of the three types of thrust bearings are compared with the experimental results, and quite good agreement between theory and experiment is obtained.

A Liquid Metal Flow Between Two Coaxial Cylinders System

2019 ◽  
Vol 11 (1) ◽  
pp. 79-86
Author(s):  
Abdelkrim Merah ◽  
Ridha Kelaiaia ◽  
Faiza Mokhtari
Keyword(s):  
Couette Flow ◽  
Metal Flow ◽  
Three Dimensional ◽  
Liquid Sodium ◽  
Taylor Vortex ◽  
Turbulent Regime ◽  
Coaxial Cylinders ◽  
Concentric Cylinders ◽  
Ideal Tool ◽  
The Stability

Abstract The Taylor-Couette flow between two rotating coaxial cylinders remains an ideal tool for understanding the mechanism of the transition from laminar to turbulent regime in rotating flow for the scientific community. We present for different Taylor numbers a set of three-dimensional numerical investigations of the stability and transition from Couette flow to Taylor vortex regime of a viscous incompressible fluid (liquid sodium) between two concentric cylinders with the inner one rotating and the outer one at rest. We seek the onset of the first instability and we compare the obtained results for different velocity rates. We calculate the corresponding Taylor number in order to show its effect on flow patterns and pressure field.

EXPERIMENTAL INVESTIGATION OF FLOW RESPONSE TO STATIONARY DISTURBANCE IN ROTATING-DISK FLOW

2019 ◽  
Vol XVI (2) ◽  
pp. 13-22
Author(s):  
Muhammad Ehtisham Siddiqui
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Careful Analysis ◽  
Laboratory Frame ◽  
Transition To Turbulence ◽  
Turbulent Regime ◽  
Mean Velocity ◽  
Layer Flow

Three-dimensional boundary-layer flow is well known for its abrupt and sharp transition from laminar to turbulent regime. The presented study is a first attempt to achieve the target of delaying the natural transition to turbulence. The behaviour of two different shaped and sized stationary disturbances (in the laboratory frame) on the rotating-disk boundary layer flow is investigated. These disturbances are placed at dimensionless radial location (Rf = 340) which lies within the convectively unstable zone over a rotating-disk. Mean velocity profiles were measured using constant-temperature hot-wire anemometry. By careful analysis of experimental data, the instability of these disturbance wakes and its estimated orientation within the boundary-layer were investigated.

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