scholarly journals Hydrodynamic Effects in a Misaligned Radial Face Seal

1979 ◽  
Vol 101 (3) ◽  
pp. 283-290 ◽  
Author(s):  
I. Etsion
Keyword(s):  
High Pressure ◽  
Analytical Solution ◽  
Strong Coupling ◽  
Axial Force ◽  
Cavitating Flow ◽  
Operating Mechanism ◽  
Face Seal ◽  
Angular Misalignment ◽  
Hydrodynamic Effects ◽  
Flat Seal

Hydrodynamic effects in a flat seal having an angular misalignment are analyzed, taking into account the radial variation in seal clearance. An analytical solution for axial force, restoring moment, and transverse moment is presented that covers the whole range from zero to full angular misalignment. Both low pressure seals with cavitating flow and high pressure seals with full fluid film are considered. Strong coupling is demonstrated between angular misalignment and transverse moment which leads the misalignment vector by 90 degrees. This transverse moment, which is entirely due to hydrodynamic effects, may be a significant factor in seal operating mechanism.

scholarly journals Radial Forces in a Misaligned Radial Face Seal

1979 ◽  
Vol 101 (1) ◽  
pp. 81-85 ◽  
Author(s):  
I. Etsion
Keyword(s):  
Analytical Solution ◽  
Radial Force ◽  
Radial Variation ◽  
Seal Ring ◽  
Face Seal ◽  
Angular Misalignment ◽  
Radial Forces ◽  
Hydrodynamic Effects

Radial forces on the primary seal ring of a flat misaligned seal are analyzed, taking into account the radial variation in seal clearance. An analytical solution for both hydrostatic and hydrodynamic effects is presented that covers the whole range from zero to full angular misalignment. The net radial force on the primary seal ring is always directed so as to produce a radial eccentricity which generates inward pumping. Although the radial force is usually very small, in some cases it may be one of the reasons for excessive leakage through both the primary and secondary seals of a radial face seal.

scholarly journals Nonaxisymmetric Incompressible Hydrostatic Pressure Effects in Radial Face Seals

1978 ◽  
Vol 100 (3) ◽  
pp. 379-383 ◽  
Author(s):  
Izhak Etsion
Keyword(s):  
High Pressure ◽  
Axial Force ◽  
Dynamic Instability ◽  
Considerable Effect ◽  
Pressure Effects ◽  
Outer Diameter ◽  
Angular Misalignment ◽  
Outer Periphery ◽  
Inner Diameter ◽  
Flat Seal

A flat seal having an angular misalignment is analyzed, taking into account the radial variations in seal clearance. An analytical solution for axial force, tilting moment, and leakage is presented that covers the whole range from zero to full angular misalignment (surfaces in contact). It is shown that nonaxisymmetric hydrostatic pressures due to the radial variations in the film thickness have a considerable effect on seal stability. When the high pressure is on the outer periphery of the seal, both the axial force and the tilting moment are nonrestoring. This causes the seal surfaces to wear at the outer diameter. Instability and wear at the inner diameter can occur when angular misalignment is combined with radial distortions and the high pressure is on the inner periphery. The case of high-pressure seals, where cavitation is eliminated, is discussed, and the possibility of dynamic instability is pointed out.

Squeeze Effects in Radial Face Seals

1980 ◽  
Vol 102 (2) ◽  
pp. 145-151 ◽  
Author(s):  
I. Etsion
Keyword(s):  
Reynolds Equation ◽  
Radius Ratio ◽  
Fluid Film ◽  
Seal Ring ◽  
Face Seal ◽  
Angular Misalignment ◽  
Damping Coefficients ◽  
Wide Range ◽  
Face Seals ◽  
Hydrodynamic Effects

Squeeze effects in a liquid lubricated radial face seal are analyzed. The analysis considers face misalignment with both axial and angular vibrations of the primary seal ring. Translational, rotational, and cross-coupled damping coefficients of the fluid film are derived analytically from a solution of the Reynolds equation utilizing the narrow seal approximation. Results are given for a wide range of practical radius ratios. At each radius ratio, the complete range of angular misalignment—from parallel faces to touch down—is covered. It is shown that squeeze effects in face seals are usually larger than the more familiar hydrodynamic effects. These effects play an important role in the seal’s mechanism of operation and therefore have to be considered in any realistic seal model.

Thermoelastohydrodynamic Behavior of Mechanical Gas Face Seals Operating at High Pressure

2007 ◽  
Vol 129 (4) ◽  
pp. 841-850 ◽  
Author(s):  
Sébastien Thomas ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Numerical Modeling ◽  
Face Seal ◽  
Inertia Effects ◽  
Real Gas ◽  
Choked Flow ◽  
Face Seals ◽  
Mechanical Face Seal ◽  
Gas Expansion

A numerical modeling of thermoelastohydrodynamic mechanical face seal behavior is presented. The model is an axisymmetric one and it is confined to high pressure compressible flow. It takes into account the behavior of a real gas and includes thermal and inertia effects, as well as a choked flow condition. In addition, heat transfer between the fluid film and the seal faces is computed, as are the elastic and thermal distortions of the rings. In the first part of this paper, the influence of the coning angle on mechanical face seal characteristics is studied. In the second part, the influence of the solid distortions is analyzed. It is shown that face distortions strongly modify both the gap geometry and the mechanical face seal’s performance. The mechanical distortions lead to a converging gap, while the gas expansion, by cooling the fluid, creates a diverging gap.

Experimental Study on Burning Process and Characteristic of Sodium Columnar Fire

2014 ◽  
Author(s):  
Ye-xin Tang ◽  
Zhi-gang Zhang ◽  
Ming Guo ◽  
Shu-bin Sun
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Stainless Steel ◽  
Temperature Field ◽  
Liquid Sodium ◽  
Maximum Temperature ◽  
Radial Temperature ◽  
Burning Process ◽  
Short Time ◽  
Hydrodynamic Effects

A variety of sodium fire generated by the leakage of liquid sodium in the FBR is common. This paper focuses on the burning process and characteristics of sodium fire in a columnar flow. About 290°C liquid sodium was injected into a 7.9 m3 stainless steel cylindrical combustion space to shape the sodium columnar fire by 0.2 MPa high pressure nitrogen. The data of temperature field for the study of burning characteristic of sodium columnar fire have been collected by the temperature acquisition system located in the combustion space. The sodium flow maintains the columnar shape at first, and disperses by hydrodynamic effects on its way down. About 64s after the initiating time of sodium ejection for this experiment, the maximum temperature of the area close to the ejection center reaches over 1200°C. And the maximum temperature appears at the space of 1–1.5m from the plate. But the high temperature lasts for a short time and reduces rapidly. The radial temperature of the area far from the sodium flow is relatively low and generally about 200°C, and maximally about 350 °C. This study is helpful to evaluate the combustion characteristics and burning process of the sodium fire in the sodium-related facilities.

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