An Investigation Into Laminar-to-Turbulent Transition in Tilting-Pad Bearings

1991 ◽  
Vol 113 (2) ◽  
pp. 303-307 ◽  
Author(s):  
G. E. Innes ◽  
H. J. Leutheusser
Keyword(s):  
Large Scale ◽  
Scale Model ◽  
Power Losses ◽  
Fluid Films ◽  
Thrust Bearings ◽  
Laminar To Turbulent Transition ◽  
Turbulent Transition ◽  
Fundamental Information ◽  
Large Scale Model ◽  
Tilting Pad

It has long been known that superlaminar flow occurs in lubrication fluid films above a critical speed. The consequence of the transition from laminar to superlaminar flow is an increase in power losses, with corresponding changes in heat generation and operating costs. While a formula exists to predict the onset of superlaminar flow for hydrodynamic journal bearings, there is no clear criterion for the transition in tilting-pad thrust bearings. The paper describes a detailed investigation, performed on a large-scale model of a single tilting-pad, to obtain fundamental information on the transition phenomenon. Based on this work a lower critical Reynolds number of laminar-to-turbulent transition is proposed.

Performance of Thrust Bearings at High Operating Speeds

1974 ◽  
Vol 96 (1) ◽  
pp. 7-13 ◽  
Author(s):  
R. S. Gregory
Keyword(s):  
Research Program ◽  
Feed Rate ◽  
Power Loss ◽  
Thrust Bearing ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Laminar To Turbulent Transition ◽  
Turbulent Transition ◽  
Tilting Pad ◽  
Bearing Loads

As part of a continuing research program, a standard 10 1/2 in. dia thrust bearing, of the tilting-pad, self-equalizing type, was tested at shaft speeds up to 11,000 rpm and bearing loads ranging up to 400 psi. The bearing and lube oil system were instrumented to measure bearing performance under laminar and turbulent operating conditions. The effects of varying the oil feed rate on bearing temperature and power loss are discussed in this paper. Some observations on the laminar to turbulent transition region are included.

Performance Characteristics of Tilting Pad Thrust Bearings at High Operating Speeds

1976 ◽  
Vol 98 (1) ◽  
pp. 81-88 ◽  
Author(s):  
J. W. Capitao
Keyword(s):  
Power Loss ◽  
Thrust Bearing ◽  
Experimental Program ◽  
Test Results ◽  
Transition Range ◽  
Thrust Bearings ◽  
Laminar To Turbulent Transition ◽  
Turbulent Transition ◽  
Tilting Pad ◽  
Bearing Loads

A full scale experimental program was conducted to investigate the influence of fluid film turbulence on the performance of the tilting-pad, self-equalizing type thrust bearing. Test results include data on centrally pivoted, 6-pad, 381-mm (15-in.) and 432-mm (17-in.) O.D. bearings operating with shaft speeds up to 10000 rpm and bearing loads ranging up to 3.447 MPa (500 psi). Data collected include bearing metal temperatures, bearing power loss, and observation of the laminar to turbulent transition range.

RANCANG BANGUN PERANGKAT EKSPERIMENTASI PROSES PIROLISIS BIOMASA GELOMBANG MIKRO

2013 ◽  
Vol 14 (2) ◽  
Author(s):  
Noor Fachrizal
Keyword(s):  
Large Scale ◽  
Continuous Model ◽  
Biomass Energy ◽  
Scale Model ◽  
Small Scale ◽  
Laboratory Apparatus ◽  
Liquid Form ◽  
Large Scale Model ◽  
Bio Oil ◽  
Pyrolysis Of Biomass

Biomass such as agriculture waste and urban waste are enormous potency as energy resources instead of enviromental problem. organic waste can be converted into energy in the form of liquid fuel, solid, and syngas by using of pyrolysis technique. Pyrolysis process can yield higher liquid form when the process can be drifted into fast and flash response. It can be solved by using microwave heating method. This research is started from developing an experimentation laboratory apparatus of microwave-assisted pyrolysis of biomass energy conversion system, and conducting preliminary experiments for gaining the proof that this method can be established for driving the process properly and safely. Modifying commercial oven into laboratory apparatus has been done, it works safely, and initial experiments have been carried out, process yields bio-oil and charcoal shortly, several parameters are achieved. Some further experiments are still needed for more detail parameters. Theresults may be used to design small-scale continuous model of productionsystem, which then can be developed into large-scale model that applicable for comercial use.

Effect of an Oscillating Flow Direction on Leading Edge Heat Transfer

1984 ◽  
Vol 106 (1) ◽  
pp. 222-228 ◽  
Author(s):  
M. L. Marziale ◽  
R. E. Mayle
Keyword(s):  
Heat Transfer ◽  
Strouhal Number ◽  
Large Scale ◽  
Flow Direction ◽  
Leading Edge ◽  
Periodic Variation ◽  
Scale Model ◽  
Transfer Rates ◽  
Large Scale Model ◽  
Turbulence Length

An experimental investigation was conducted to examine the effect of a periodic variation in the angle of attack on heat transfer at the leading edge of a gas turbine blade. A circular cylinder was used as a large-scale model of the leading edge region. The cylinder was placed in a wind tunnel and was oscillated rotationally about its axis. The incident flow Reynolds number and the Strouhal number of oscillation were chosen to model an actual turbine condition. Incident turbulence levels up to 4.9 percent were produced by grids placed upstream of the cylinder. The transfer rate was measured using a mass transfer technique and heat transfer rates inferred from the results. A direct comparison of the unsteady and steady results indicate that the effect is dependent on the Strouhal number, turbulence level, and the turbulence length scale, but that the largest observed effect was only a 10 percent augmentation at the nominal stagnation position.

Large scale model tests on Royal Schelde SES

1989 ◽  
Author(s):  
R. DE GAAIJ ◽  
E. VAN RIETBERGEN ◽  
M. SLEGERS
Keyword(s):  
Large Scale ◽  
Model Tests ◽  
Scale Model ◽  
Large Scale Model

Experimental Study on the Behavior of a Swimming Pool Onboard a Large Passenger Ship

2009 ◽  
Vol 46 (01) ◽  
pp. 27-33
Author(s):  
Pekka Ruponen ◽  
Jerzy Matusiak ◽  
Janne Luukkonen ◽  
Mikko Ilus
Keyword(s):  
Large Scale ◽  
Hydraulic Cylinder ◽  
Operating Conditions ◽  
Swimming Pool ◽  
Scale Model ◽  
Longitudinal Motion ◽  
Sea State ◽  
Passenger Ship ◽  
Large Scale Model ◽  
Computer Controlled

The water in a swimming pool on the top deck of a large passenger ship can be excited to a resonant motion, even in a moderate sea state. The motion of the water in the pool is mainly caused by longitudinal acceleration, resulting from the ship's pitch and surge motions. At resonance, there can be high waves in the pool and splashing of water. In this study the behavior of the Solarium Pool of the Freedom of the Seas was examined in various sea states and operating conditions. The motions of the pool were calculated on the basis of a linear seakeeping method, and the behavior of the water in the pool was studied with experimental model tests. A large-scale model of the pool was constructed and fitted to a purpose-built test bench that could be axially moved by a computer-controlled hydraulic cylinder. Water elevation in the pool was measured, and all tests were video recorded. Different modifications of the pool were tested to improve the behavior of the pool. A strong correlation between the longitudinal motion and the behavior of the water in the pool was found.

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