An Experimental Investigation Into the Thermohydrodynamic Behavior of a High Speed Cylindrical Bore Journal Bearing

1985 ◽  
Vol 107 (4) ◽  
pp. 538-543 ◽  
Author(s):  
D. T. Gethin ◽  
J. O. Medwell
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Transitional Flow ◽  
Outlet Temperature ◽  
Test Apparatus ◽  
Supportive Evidence ◽  
Design Procedures ◽  
Cylindrical Bore ◽  
Complex Temperature

A description of the design of a high speed journal bearing test apparatus and some results recorded from a cylindrical bore bush fed by two axial grooves are presented. These highlight the complex temperature patterns which are generated in the bush. To compliment this detailed information, the variation of load capacity, bush torque reaction, leakage, and bulk outlet temperature with speed are presented also. The work suggests that Taylor’s criterion may be applied broadly to determine the onset of non laminar flow in bearings. It also provides supportive evidence concerning the applicability of design procedures used in the transitional flow regime.

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

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Eckhard Schüler ◽  
Olaf Berner
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Fluid Film ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Tilting Pad ◽  
Bearing Load ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

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.

Analysis of Hybrid (Hydrodynamic/Hydrostatic) Journal Bearing

2013 ◽  
Vol 650 ◽  
pp. 385-390 ◽  
Author(s):  
Vijay Kumar Dwivedi ◽  
Satish Chand ◽  
K.N. Pandey
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Gas Turbines ◽  
High Speed ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Natural Boundary Condition ◽  
Dimensional Solution

The Hybrid (hydrodynamic/ hydrostatic) journal bearing system has found wide spread application in high speed rotating machines such as compressors, gas turbines, steam turbines, etc. The present studies include solution of Reynolds equation for hydrodynamic journal bearing with infinitely long approximation (ILA), infinitely short bearing approximation (ISA) and finite journal bearing approximation. Further Finite Journal bearing approximation considers two dimensional solution of Reynolds equation with natural boundary condition, which cannot be solved by analytical method. So, here the solutions for finite journal bearing have been done with finite difference method (a MATLAB® code is prepared for finite difference method) to get bearing performance parameters such as load capacity, Sommerfeld no., etc.

Paper 8: An Experimental Investigation of the Floating-Pad Journal Bearing

1969 ◽  
Vol 184 (12) ◽  
pp. 54-59
Author(s):  
R. B. Howarth
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Excited Vibration ◽  
Low Load ◽  
Static Performance

This paper describes an experimental investigation into the static performance of a floating-pad journal bearing with four pads. Up to moderate eccentricities the test bearing was found to have a somewhat greater load capacity than an equivalent plain journal bearing, and there was no evidence of instability. The geometry of the bearing also allows high lubricant flows to be used for cooling purposes without requiring excessive supply pressures. Some difficulties were experienced with starting under load and with a self-excited vibration which occurred at moderate to high eccentricities. The results of the investigation suggest that this form of bearing is most suitable for low-load, high-speed applications.

Advancements in the Performance of Aerodynamic Foil Journal Bearings: High Speed and Load Capability

1994 ◽  
Vol 116 (2) ◽  
pp. 287-294 ◽  
Author(s):  
H. Heshmat
Keyword(s):  
High Speed ◽  
Room Temperature ◽  
Journal Bearing ◽  
Load Capacity ◽  
Ambient Pressure ◽  
Journal Bearings ◽  
Test Results ◽  
Rotor Speed ◽  
Turbine Wheel ◽  
Dynamic Analyses

An advanced-design, aerodynamic, air-lubricated foil journal bearing achieved a landmark speed of 2200 cps (132,000 rpm) and a major breakthrough in load performance of 673.5 kPa (97.7 psi). At 20°C (68°F) room temperature, normal ambient pressure, 995 cps (59,700 rpm) rotor speed, and with bearing projected pad area of 1081 mm2 (1.675 in2), the bearing demonstrated a load capacity of 727.8 N (163.6 lb). The bearing also exhibited low heat generation, with about 40°C (104°F) average side leakage temperature rise. For this demonstration, a highspeed spindle utilizing a pair of 35-mm (1.375-in.) bearings and supporting a test rotor with a mass of 1.545 kg (weighing 3.41 lb) and overall length of 211 mm (8.3 in.) was successfully taken to the limiting speed of the test apparatus. This speed was set by the maximum sound velocity (Mach 1) in the spindle’s turbine wheel. The rotor/bearing speed of 4.62 × 106 DN is beyond the capability of any advanced oil-lubricated ball bearings or conventional gas-lubricated bearings. The net result is a highly stable bearing at high operating speed. This paper presents the development of this air-lubricated foil journal bearing, the operational procedures used during testing, test results (dynamic analyses), and load performance characteristics.

Performance of Adaptive Lubricants in a Hybrid Journal Bearing Operating Under Fully Saturated Conditions

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Ssu-Ying Chien ◽  
M. S. Cramer ◽  
Gen Fu ◽  
Alexandrina Untaroiu
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Fluid Dynamic ◽  
Load Capacity ◽  
Three Dimensional ◽  
Co2 Concentration ◽  
Dissolved Carbon ◽  
Synthetic Oil ◽  
Low Viscosity ◽  
Carbon Dioxide Co2

Adaptive lubricants involve binary mixture of synthetic oil and dissolved carbon dioxide (CO2). Unlike conventional lubricant oils, the lubricant viscosity not only varies with the temperature within the bearing but also can be directly adjusted through the CO2 concentration in the system. In this study, we consider the synthetic oil to be fully saturated by CO2 to investigate the maximum impacts of adaptive lubricants on the performance of a hybrid journal bearing. The adaptive lubricant analyzed for this study was the polyalkylene glycol (PAG) oil with low concentration of CO2 (<30%). A three-dimensional (3D) computational fluid dynamic (CFD) model of the bearing was developed and validated against the experimental data. The mixture composition and the resultant mixture viscosity were calculated as a function of pressure and temperature using empirical equations. The simulation results revealed that the viscosity distribution within the PAG/CO2-lubricated bearing is determined primarily by the pressure at the low operating speed. When the speed becomes higher, it is the temperature effect that dominates the viscosity distribution within the bearing. Moreover, the PAG/CO2-lubricated bearing can reduce up to 12.8% power loss than the PAG-lubricated bearing due to the low viscosity of PAG/CO2 mixture. More importantly, we have found that the PAG/CO2 can enhance the load capacity up to 19.6% when the bearing is operating at high-speed conditions.

Three-dimensional computational fluid dynamic analysis of high-speed water-lubricated hydrodynamic journal bearing with groove texture considering turbulence

2021 ◽  
pp. 135065012199851
Author(s):  
Huihui Feng ◽  
Shuyun Jiang ◽  
Yanqin Shang-Guan
Keyword(s):  
Computational Fluid Dynamic ◽  
High Speed ◽  
Journal Bearing ◽  
Fluid Dynamic ◽  
Load Capacity ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Computational Fluid Dynamic Analysis ◽  
Hydrodynamic Journal Bearing ◽  
Groove Texture

Water-lubricated bearings have attracted increasing attention in the field of high-speed machine tools for their low friction due to low viscosity. However, new problems, in particular, insufficient load capacity, are on the way. To the point, groove-textured journal bearing is adopted in this study. Aiming at investigating the effects of groove texture on high speed, water-lubricated, hydrodynamic journal bearing precisely, and thoroughly, three-dimensional computational fluid dynamic analyses considering cavitation and turbulence are undertaken to assess the tribological performances of the bearing. To reduce the amount of three-dimensional modeling and meshing work, mesh deformation is presented. The numerical results are compared with experiments to verify the validity of the present models and calculation procedures. Pressure distribution, load capacity, and friction of groove-textured water-lubricated journal bearing are analyzed with respect to operating conditions and geometric parameters. Comparisons between groove-textured water-lubricated journal bearing and smooth bearing are carried out to find out the influence of groove texture. It is found that the groove texture can achieve a remarkable improvement of load capacity at a smaller eccentricity ratio and higher rotary speed. The load capacity is affected by the combined effects of groove depth, width, and length. However, generally, the friction force of water-lubricated journal bearing is slightly influenced by groove texture. Results can provide theoretical guidance for the optimal design of groove-textured water-lubricated journal bearing under different operating parameters.

Development of Foil Journal Bearings for High Load Capacity and High Speed Whirl Stability

1982 ◽  
Vol 104 (2) ◽  
pp. 149-156 ◽  
Author(s):  
H. Heshmat ◽  
W. Shapiro ◽  
S. Gray
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
High Load ◽  
Operating Speed ◽  
High Load Capacity

This paper describes the development of two types of air-lubricated foil journal bearings, designed for separate purposes; stability and load capacity. The first was a three-pad configuration, with each pad forming a wedge whose convergence increases with operating speed (of 120,000 rpm max.). The net result is a highly stable bearing at high operating speed. The second was a single pad journal bearing (43.7 mm diameter × 34.9 mm long) that produced a load capacity of 352 KPa (51 psi) at an operating speed of 68,000 rpm.

Performance of Adaptive Lubricants in a Hybrid Journal Bearing Operating Under Fully Saturated Conditions

2017 ◽  
Author(s):  
Ssu-Ying Chien ◽  
Mark Cramer ◽  
Gen Fu ◽  
Alexandrina Untaroiu
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Fluid Dynamic ◽  
Load Capacity ◽  
Three Dimensional ◽  
Co2 Concentration ◽  
Dissolved Carbon ◽  
Synthetic Oil ◽  
Low Viscosity ◽  
Carbon Dioxide Co2

Adaptive lubricants involve binary mixture of synthetic oil and dissolved carbon dioxide (CO2). Unlike conventional lubricant oils, the lubricant viscosity not only varies with the temperature within the bearing, but also can be directly adjusted through the CO2 concentration in the system. In this study, we investigated the performance of adaptive lubricants in a hybrid journal bearing considering the synthetic oil to be fully saturated by CO2. The adaptive lubricant analyzed for this study was the polyalkylene glycol (PAG) oils with low concentration of CO2 (< 30%). A three-dimensional computational fluid dynamic (CFD) model of the bearing was developed and validated against the experimental data. The mixture composition and the resultant mixture viscosity were calculated as a function of pressure and temperature using empirical equations. The simulation results revealed that the viscosity distribution within the PAG/CO2-lubricated bearing is determined primarily by the pressure at the low operating speed. When the speed becomes higher, it is the temperature effect that dominates the viscosity distribution within the bearing. Moreover, the PAG/CO2-lubricated bearing can reduce up to 12.8% power loss than the PAG-lubricated bearing due to the low viscosity of PAG/CO2 mixture. Most importantly, we have found the PAG/CO2 can enhance the load capacity up to 19.6% when the bearing is operating at the high speed conditions.

A General Solution of Reynolds’ Equation for a Full Finite Journal Bearing

1967 ◽  
Vol 89 (2) ◽  
pp. 203-210 ◽  
Author(s):  
R. R. Donaldson
Keyword(s):  
Fourier Series ◽  
Series Solution ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Separation Of Variables ◽  
Hill Equation ◽  
Eigenvalues And Eigenvectors ◽  
General Series ◽  
Bearing Load

Reynolds’ equation for a full finite journal bearing lubricated by an incompressible fluid is solved by separation of variables to yield a general series solution. A resulting Hill equation is solved by Fourier series methods, and accurate eigenvalues and eigenvectors are calculated with a digital computer. The finite Sommerfeld problem is solved as an example, and precise values for the bearing load capacity are presented. Comparisons are made with the methods and numerical results of other authors.

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