Axial squeeze film systems - Parametric study and their relative contributions as bearings and dampers

The current trend in turbomachine design to achieve increased power to weight ratio is to increase its designed operating speed which implies that rotors have to operate supercritically. To ensure the smooth crossover of critical speeds, radial squeeze film dampers having end13; seals to regulate the flow of damping oil were hitherto being used.The modern trend however is to replace the metallic end seals by what are called 'sideplates' with a small clearance in the axial direction into which damping oil could be introduced to enhance damping capabilities thus leading to the concept of 'Axial Squeeze Film13; Systems'. This paper presents some details regarding the experimental investigation of such an axial squeeze film system and attempts to clearly demarcate the behavior of the axial squeeze film under dynamic loading conditions as being analogous to that of a damper or of a bearing. Experimental results indicate that a specified combination of damper/bearing diameter and mean film thickness at a known running excitation frequency influences the axial squeeze film system to behave as a bearing or as a damper. The effects of geometric parameters like mean film thickness and plate diameter on damping coefficient are also discussed in this paper