An Optimum Step Design for Centering of Pistons

1975 ◽  
Vol 97 (4) ◽  
pp. 621-624
Author(s):  
I. Etsion
Keyword(s):  
Circular Cylinder ◽  
Incompressible Fluid ◽  
Design Parameter ◽  
Performance Characteristics ◽  
Step Height ◽  
Small Eccentricity

A stepped lands piston enclosed within a tight circular cylinder of uniform bore and subjected to unequal upstream and down-stream boundary pressures is analysed for the case of incompressible fluid. Performance characteristics are given for small eccentricity ratios as a function of the step height and location, and a design parameter which relates the leakage and the centering force is defined. It is shown that piston performance can bo optimized by selecting a proper step design.

An Optimum Stepped Piston for Cylinders Working With Compressible Fluid

1976 ◽  
Vol 98 (3) ◽  
pp. 494-498 ◽  
Author(s):  
I. Etsion
Keyword(s):  
Circular Cylinder ◽  
Compressible Fluid ◽  
Design Parameter ◽  
Pressure Ratio ◽  
Performance Characteristics ◽  
Step Size ◽  
Small Eccentricity

A stepped piston, enclosed within a tight circular cylinder of uniform bore and subjected to unequal upstream and downstream boundary pressures, is analyzed for the case of a compressible fluid. Performance characteristics are given for small eccentricity and high boundary pressure ratio as a function of step size and location, and a design parameter that relates the leakage and the centering force is defined. It is shown that piston performance can be optimized by suitable step design.

The Hydrodynamics of a Plug Bearing

1976 ◽  
Vol 98 (3) ◽  
pp. 433-440 ◽  
Author(s):  
I. Etsion ◽  
O. Pinkus
Keyword(s):  
Incompressible Fluid ◽  
Body Shape ◽  
Operating Conditions ◽  
The Body ◽  
Resultant Force ◽  
Performance Characteristics ◽  
Wide Range ◽  
Narrow Interspace

The notion of a “plug” bearing taken up in this work refers to bodies moving within tight circular conduits. Our interest lies in the hydrodynamic film generated in the narrow interspace between body and wall under conditions of an incompressible fluid and unequal boundary pressures. For generality rotation as well as translation is considered. Performance characteristics are given for nontilting frustums, both diverging and converging in the direction of motion. It is shown that for a given body shape the amount of leakage past the plug is the same regardless of its orientation. However, with geometries whose film increases in the direction of plug velocity there is a wide range of operating conditions when the resultant force is such as to drive the body against the wall of the conduit; over the same range, shapes which produce films decreasing in the direction of motion yield a floating force.

Stability of a Rotor Partially Filled With a Viscous Incompressible Fluid

1979 ◽  
Vol 46 (4) ◽  
pp. 913-918 ◽  
Author(s):  
S. L. Hendricks ◽  
J. B. Morton
Keyword(s):  
Angular Velocity ◽  
Circular Cylinder ◽  
Incompressible Fluid ◽  
Parametric Study ◽  
Viscous Incompressible Fluid ◽  
Constant Angular Velocity ◽  
Unstable Region ◽  
Stability Boundaries ◽  
System Parameters ◽  
Linear Spring

A hollow circular cylinder rotating with constant angular velocity and partially filled with a viscous incompressible fluid has been analyzed for stability. The analysis can be extended to apply to many different rotor geometries. The results of this analysis predict that over a range of operating speeds, the system is unstable. The extent of this unstable region is determined by the system parameters. The interplay between viscosity of the fluid and damping on the rotor is especially important in determining stability boundaries. A parametric study is presented for a rotor modeled as a cup in the middle of a symmetrically supported massless shaft. The rotor is subject to a linear spring and a linear damper. Rotor unbalance, gravity, and axial effects are considered negligible.

High-speed flow of a gas past an approximately elliptic cylinder

1950 ◽  
Vol 46 (3) ◽  
pp. 479-491 ◽  
Author(s):  
H. C. Levey
Keyword(s):  
Circular Cylinder ◽  
General Theory ◽  
Incompressible Fluid ◽  
Exact Solutions ◽  
High Speed ◽  
Elliptic Cylinder ◽  
Two Dimensional ◽  
High Speed Flow ◽  
Speed Flow ◽  
Two Dimensional Flow

AbstractIn this paper, a family of exact solutions of the problem of two-dimensional flow of a compressible perfect fluid about a cylinder is found, the solutions being generalized from those for the flow of an incompressible fluid about an elliptic cylinder of arbitrary eccentricity and angle of attack. The circulation is taken to be zero and the speed of the fluid at infinity subsonic. This analysis is an application of the general theory given by T. M. Cherry (1, 2); it was done to exhibit the details of the analysis for a flow other than that corresponding to the low-speed flow past a circular cylinder.

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