Accession Number : ADA138054

Title :   The Effect of Fluid Inertia and Viscoelasticity in Squeeze-Film Damper Bearings.

Descriptive Note : Final rept. 15 Sep 80-30 Nov 83,

Corporate Author : RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Tichy,J A

PDF Url : ADA138054

Report Date : Jan 1984

Pagination or Media Count : 28

Abstract : In the modeling and analysis of rotor dynamic systems, the behavior of squeeze film damper bearings is normally predicted by the Reynolds equation of hydrodynamic lubrication. Large bearing gaps and high speeds can combine to create conditions in practical applications where fluid inertia and viscoelastic effects may become significant, violating the assumptions under which Reynolds equation can be applied. The analysis shows that the results of lubrication theory can be greatly in error with regard to phase effects between bearing forces and displacements, which may have profound implications regarding critical speed and forced response behavior. Very large deviations from lubrication theory have been predicted in a series of analytical papers under this contract. In the present study direct measurements of damper forces are presented for the first time. Reynolds numbers up to ten are obtained at eccentricity ratios 0.2 and 0.5. Lubrication theory underpredicts the measured forces by up to a factor of two (100% error). Qualitative agreement is found with predictions of the improved theory which includes fluid inertia forces.

Descriptors :   *Bearings, *Turbomachinery, *Lubricants, *Oils, *Fluid dynamics, *Inertia, *Viscoelasticity, Qualitative analysis, Failure(Mechanics), Rotors, Aircraft engines, Gas turbines, Reynolds number, Loads(Forces), Displacement, Performance(Engineering), High velocity, Theorems, Equations

Subject Categories : Organic Chemistry
      Numerical Mathematics
      Machinery and Tools
      Fluid Mechanics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE