Characteristics of Squeeze Air Film Between Nonparallel Plates

1983 ◽  
Vol 105 (1) ◽  
pp. 147-152 ◽  
Author(s):  
H. Takada ◽  
S. Kamigaichi ◽  
H. Miura
Keyword(s):  
Pressure Transducer ◽  
Dynamic Pressure ◽  
Air Flow ◽  
Approximate Solutions ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Flow Through ◽  
Air Film ◽  
Theoretical Results ◽  
Good Agreement

The dynamic pressure in a squeeze film and the air flow through the film were analyzed experimentally and theoretically. The dynamic pressure was measured in a squeeze film between two rectangular plates with a small pressure transducer. Approximate solutions for the rectangular squeeze film were obtained analytically. The results were valid for small excursion ratios. Next, a squeeze film between nonparallel plates (wedge film) was examined. In this case, steady air flow occurred due to the unsymmetry of the pressure distribution. To investigate this fact, the air flow was measured in a spherical squeeze film. The values showed good agreement with the theoretical results.

Sealing Effects of Squeeze Air Film

1986 ◽  
Vol 108 (4) ◽  
pp. 594-597 ◽  
Author(s):  
H. Takada ◽  
S. Kamigaichi ◽  
H. Miura
Keyword(s):  
Flow Rate ◽  
Vibration Amplitude ◽  
Ambient Pressure ◽  
Air Flow ◽  
Face Seal ◽  
Air Flow Rate ◽  
The Difference ◽  
Air Film ◽  
Theoretical Results ◽  
Good Agreement

The sealing effects of squeeze air film were analyzed experimentally and theoretically. The air flow rate and the sealed pressure were measured in a squeeze face seal. The air flow rate can be expressed as the difference between the flow rate by the pumping and the flow rate by the leakage. The air flow rate by the pumping increases proportionally to the square of the vibration amplitude of the surface, as does the sealed pressure. The air flow rate by the leakage increases proportionally to the pressure difference between the vessel pressure and the ambient pressure. The experimental results showed good agreement with the theoretical results.

An Investigation of the Squeeze Film Between Rotating Annuli

1970 ◽  
Vol 92 (3) ◽  
pp. 435-440 ◽  
Author(s):  
C. W. Allen ◽  
A. A. McKillop
Keyword(s):  
Experimental Investigation ◽  
Melting Point ◽  
Liquid Metal ◽  
Decay Rates ◽  
Squeeze Film ◽  
Centrifugal Effect ◽  
Experimental Values ◽  
Free Falling ◽  
Air Film ◽  
Good Agreement

The squeeze film between two plane annuli is examined theoretically and experimentally. The theoretical analysis considers the inertia due to the “centrifugal effect” but neglects all other inertia terms. The experimental investigation is by means of a free-falling spinning rotor which is decelerated by the squeeze film. Fluids examined are kerosene, SAE 10 oil, and a low melting point liquid metal. Good agreement between the predicted and actual decay rates is obtained for kerosene but that for the oil and liquid metal is only fair. The theoretical and experimental values of film thickness are in good agreement. The results for the liquid metal suggest the possibility of a thin air film between the rotor and the liquid metal.

Approximate Phase Change Solutions for Insulated Buried Cylinders

1983 ◽  
Vol 105 (1) ◽  
pp. 25-32 ◽  
Author(s):  
V. J. Lunardini
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Numerical Solutions ◽  
Single Point ◽  
Approximate Solutions ◽  
Burial Depth ◽  
Pipe Surface ◽  
Insulation Thickness ◽  
Theoretical Results ◽  
Good Agreement

The conduction problem for cylinders embedded in a medium with variable thermal properties cannot be solved exactly if phase change occurs. New, approximate solutions have been found using the quasi-steady method. These solutions consider heat flow from the entire pipe surface, rather than from a single point, as has been assumed in the past. The temperature field, phase change location, and pipe surface heat transfer can be evaluated using graphs presented for parametric ranges of temperature, thermal properties, burial depth, and insulation thickness. The theoretical results show good agreement with complete numerical solutions. The accuracy of the method increases as the Stefan number decreases and the results are of particular value for insulated hot pipes or refrigerated gas lines.

Fluid Flow in Perforated Pipes

1975 ◽  
Vol 17 (6) ◽  
pp. 338-347 ◽  
Author(s):  
B. J. Bailey
Keyword(s):  
Fluid Flow ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Pipe Wall ◽  
Air Flow ◽  
Diameter Ratio ◽  
Friction Loss ◽  
Flow Through ◽  
Good Agreement ◽  
Air Discharge

Values of the discharge coefficient for air flow through single holes in a pipe wall, and for the angle of efflux are reported. The variation of static pressure along tubular polyethylene air ducts with a maximum length-to-diameter ratio of 250 containing pairs of diametrically opposed holes has been measured. This information was used with data on friction loss to determine values for the coefficient of static pressure regain. It was possible to predict variations in static pressure and air discharge along uniformly perforated ducts which were in good agreement with those observed experimentally.

Dynamic Characteristics of Hydrostatic Thrust Air Bearing With Actively Controlled Restrictor

1988 ◽  
Vol 110 (1) ◽  
pp. 156-161 ◽  
Author(s):  
Yuichi Sato ◽  
K. Maruta ◽  
M. Harada
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Phase Lag ◽  
Air Bearing ◽  
Plate Vibrations ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Air Film ◽  
Theoretical Results ◽  
Good Agreement

The dynamic characteristics of a hydrostatic thrust air bearing with an actively controlled orifice restrictor are investigated theoretically and experimentally. Theoretical results show that the dynamic stiffness and damping coefficients can be increased simultaneously when the restrictor area is controlled with appropriate phase-lag to the change of air film thickness, that is, plate vibrations. Consequently stability of the bearing can be improved. Experimental results show fairly good agreement with theoretical ones.

Some Contributions to Experimental Combustion Research

1969 ◽  
Vol 184 (10) ◽  
pp. 203-211 ◽  
Author(s):  
J. Rödig ◽  
F. Žalud
Keyword(s):  
Combustion Chamber ◽  
Steady Flow ◽  
Diesel Engines ◽  
Evaporation Rate ◽  
Dynamic Pressure ◽  
Air Flow ◽  
Spectrographic Analysis ◽  
Chemical Changes ◽  
Flow Through ◽  
Flow Velocities

Techniques of measuring air flow through inlet ducts of diesel engines and tangential air velocities in the cylinder are investigated. An impulse wheel anemometer and conical pressure pick-up are used to measure steady flow velocities. Air velocities in the combustion chamber are evaluated from dynamic pressure variations indicated by tensometric pick-ups. Chemical changes of the fuel during combustion in the cylinder are studied with the help of spectrographic analysis. The evaporation rate of fuel injected into the cylinder is measured by analysis of fuel luminescence.

Modeling and simulation of sheets ply separation induced by air flow

2019 ◽  
Vol 37 (4) ◽  
pp. 1133-1153
Author(s):  
Xin He ◽  
XiaoPing Li ◽  
Jinrong Yang
Keyword(s):  
High Speed ◽  
Dynamic Pressure ◽  
Air Flow ◽  
Separation Distance ◽  
Parameter Analysis ◽  
Restoring Force ◽  
Content Type ◽  
Interaction Simulation ◽  
Flow Through ◽  
Main Factor

Purpose The purpose of this paper is to investigate the mechanism of sheets ply separation induced by air flow through numerical simulation with two-way FSI (fluid-structure interaction) simulation using ANSYS and theoretical speculation. Design/methodology/approach The paper primarily establishes a simplified physical model of the sheets ply separation induced by air flow. Then, the force of the air flow acting on the sheet has been analyzed based on the model, and the main factor leading to separation was obtained. Furthermore, the parameter analysis was investigated based on linear stability analysis, from which the factors that affect stable separation are obtained. Finally, a series of numerical simulations are performed to verify the conclusions. Findings This study shows that the main separation factor is the variable air pressure in the gap between the sheets caused by the dynamic pressure air flow. Increasing the inlet velocity of the flow field will increase the separation distance but excessive velocity will lead to instability. The viscous resistance acting on the sheet and the bending stiffness of the sheet are factors that stabilize the system, and the sheet density and the restoring force can lead to instability. Originality/value The paper is one of the first in the literature that investigates the problem of sheets ply separation induced by air flow, which is the primary method for multi-layer separation in sheets de-stacking operations, especially for the high-speed occasion.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

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