Abstract
The numerical prediction of the dynamical behavior of turbopumps is very important. The space technology and the field of energy products are in constant development and it is necessary to quantify the influence of each component. The dynamical characteristics of annular seals must be calculated with accuracy.
The aim of this work is to quantify the influence of geometric parameters on the dynamical behavior of the shaft.
Three parameters will be studied: the duct loss parameter (at the seal entrance), a conical seal, and a misaligned seal. The two last geometrical defects have a direct influence on the film thickness.
It is important to insist on the influence of the entrance duct loss which governs, in large part, the stiffness calculus (and then the stability). The most difficult problem is to evaluate this duct loss which depends on the seal geometry, Reynolds number and fluid characteristics...
This study shows the important rôle played by geometrical parameter of a seal. The conicity and the misalignment modify the dynamical behavior of the shaft. These effects are essentially due to the axial flow which generates a pressure field due to axial film geometry. It should be noted that in the case of predominant circumferential flow these conclusions are totally different.