Dynamics of pressure pulsations in thin annular gap

Abstract

Fluid pulsations can significantly influence behavior of bearings or sealing parts of hydraulic machines and therefore their operation. In this contribution, an analytical approach to solve pressure pulsations dynamics is compared with a computational solution using acoustic simulation in ANSYS Mechanical FEM package. Studied problem is simplified to an annular gap and the pressure pulsations are excited either from one annulus end or excitation is made by a movement of an inner cylindrical surface perpendicularly to its axis. Excitation on an annulus surface can have angle dependent phase. This geometry allows a linearization of governing equations and so the equations are solvable analytically. Compressibility was incorporated to analytical and computational approach so the eigen frequencies for both methods were evaluated and compared. Also the added fluid effects were studied and evaluated.Fluid pulsations can significantly influence behavior of bearings or sealing parts of hydraulic machines and therefore their operation. In this contribution, an analytical approach to solve pressure pulsations dynamics is compared with a computational solution using acoustic simulation in ANSYS Mechanical FEM package. Studied problem is simplified to an annular gap and the pressure pulsations are excited either from one annulus end or excitation is made by a movement of an inner cylindrical surface perpendicularly to its axis. Excitation on an annulus surface can have angle dependent phase. This geometry allows a linearization of governing equations and so the equations are solvable analytically. Compressibility was incorporated to analytical and computational approach so the eigen frequencies for both methods were evaluated and compared. Also the added fluid effects were studied and evaluated.