An Experimental Investigation of the Effect of Misalignment and Directionality on the Performance of an Externally-Pressurized, Orifice-Compensated Air Journal Bearing

1979 ◽  
Vol 101 (1) ◽  
pp. 28-37 ◽  
Author(s):  
P. H. Markho ◽  
S. S. Grewal ◽  
T. B. Stowell
Keyword(s):  
Experimental Investigation ◽  
Journal Bearing ◽  
Diameter Ratio ◽  
Performance Characteristics ◽  
Double Plane ◽  
Order Of Magnitude ◽  
Length To Diameter Ratio

The study described in this paper aims to quantify the effects of misalignment and directionality on the important performance characteristics of a double-plane admission bearing having a length to diameter ratio of unity. The results clearly demonstrate that misalignment does not seriously impair the bearing performance, as long as due allowance is made for its effect on clearance at the bearing ends. In practice, this impairment would rarely exceed 10 percent. The effect of directionality is also found to be of the same order of magnitude.

The Effects of Oil Supply Pressure at different Groove Position on Temperature and Pressure Profile in Journal Bearing

2013 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
R. S. Dwyer-Joyce ◽  
Aidah Jumahat
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Diameter Ratio ◽  
Radial Load ◽  
Oil Supply ◽  
Supply Pressure ◽  
Pressure Profiles ◽  
Hydrodynamic Journal Bearing ◽  
Temperature And Pressure ◽  
Length To Diameter Ratio

The effects of oil supply pressure on the temperature and pressure at different groove locations on a hydrodynamic journal bearing were investigated. A journal with a diameter of 100 mm and a ½ length-to-diameter ratio was used. The supply pressure was set to 0.2, 0.5, and 0.7 MPa at seven different groove locations, namely, -45°, -30°, -15°, 0°, +15°, +30°, and +45°. Temperature and pressure profiles were measured at speed values of 300, 500, and 800 rpm with 10 kN radial load. The results show that the change in oil supply pressure simultaneously reduced the temperature and increased the pressure profile.

Analysis of a Finite Grooved Misaligned Journal Bearing Considering Cavitation and Starvation Effects

1990 ◽  
Vol 112 (1) ◽  
pp. 60-67 ◽  
Author(s):  
D. Vijayaraghavan ◽  
T. G. Keith
Keyword(s):  
Journal Bearing ◽  
Numerical Procedure ◽  
Diameter Ratio ◽  
Film Rupture ◽  
Supply Pressure ◽  
Starvation Effects ◽  
Inlet Conditions ◽  
Journal Misalignment ◽  
Length To Diameter Ratio

The effect of journal misalignment on the predicted performance of a finite grooved journal bearing is analyzed in this paper. The numerical procedure used incorporates a cavitation algorithm, which automatically predicts film rupture and reformation in the bearings. The misalignment considered varies in magnitude and direction with reference to the boundaries of the bearing. In addition to the misalignment, the effect of lubricant starvation at the groove is also considered and compared with flooded inlet conditions. The effects of various degrees of starvation, or higher lubricant supply pressure, bearing length to diameter ratio and groove size are also investigated.

Performance of a Closed-Tube Aerosyphon With Large Length-Diameter Ratios

1989 ◽  
Vol 111 (4) ◽  
pp. 337-343
Author(s):  
G. S. H. Lock ◽  
J. D. Kirchner
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Single Phase ◽  
Diameter Ratio ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
General Terms ◽  
Closed Tube ◽  
Order Of Magnitude ◽  
Large Length

The paper reports an experimental investigation of heat transfer in the closed-tube aerosyphon (aerated-thermosyphon) for a range of conditions representative of northern field applications. In particular, attention is focused on the effect of using tubes with heated lengths not only greater than the cooled lengths, but very much greater than the tube diameter. Using three heated sections and one cooled section, the geometry of the device has been varied systematically with 10 < LH/d < 50 and 1 < LH/LC < 20. For any given geometry, the effect of air bubbling rate has been studied in the range of 0 < V˙ < 5 × 10−5 m3/S. Using these ranges it has been possible to make comparisons with other thermosyphon and aerosyphon data. The results indicate that heat transfer coefficients are reduced by increasing either length-diameter ratio or heated-cooled length ratio. They also reveal that, in general terms, the aerosyphon is almost an order-of-magnitude more effective than the single-phase thermosyphon. Some obervations on the flow regimes are offered, and an empirical correlation is presented.

Pressure Attenuation in Long Rarefaction Wave Tubes

1969 ◽  
Vol 91 (2) ◽  
pp. 497-500
Author(s):  
M. J. Levy ◽  
H. Gerecke ◽  
J. H. Potter
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Rarefaction Wave ◽  
Initial Pressure ◽  
Diameter Ratio ◽  
Rarefaction Waves ◽  
Gas Dynamic ◽  
Large Length ◽  
Length To Diameter Ratio

This paper reports upon an experimental investigation of gas dynamic rarefaction waves in rarefaction wave tubes to determine effects of large length to diameter ratios. A fitted equation is presented from which reasonable predictions can be made on the pressure deviation between a real and an ideal rarefaction wave. Transient boundary-layer effects cause an attenuation of the pressure which becomes more pronounced as the length to diameter ratio is increased. At a length to diameter ratio of 895, the pressure damping was essentially complete in one cycle for initial pressure ratios in excess of 1.6.

Optimized growth of high length-to-diameter ratio Lu2O3 single crystal fibers by the LHPG method

CrystEngComm ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 1657-1662
Author(s):  
Na Zhang ◽  
Yuqing Yin ◽  
Jian Zhang ◽  
Tao Wang ◽  
Siyuan Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
High Power ◽  
Diameter Ratio ◽  
Solid State Lasers ◽  
Crystal Fibers ◽  
High Length ◽  
Length To Diameter Ratio

Lu2O3 crystals have attracted intense attention due to their great potential in the field of high power solid-state lasers.

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