3.2.5 Matching of a damper performances to a rotor system
HD stiffness and damping depend on rotor displacements in clearance so it is nesessary to match the rotor and HD dynamic performances as to apply the parametric analysis stiffness and damping coefficients. The calculation milestone points are given below.
- Stiffness and damping are calculated at preliminary determined damper dimensions (length, diameter, clearance and eccentricity e0 = 0.4 to 0.5. Desired values are near to the values obtained at parametric study.
- At given unbalance distribution the rotor loads and displacements are calculated. Damper displacements determine eccentricity e1.
- The obtained e1 value is compared to preliminary taken e0. If the difference is considerable the initial e0 value is changed and the (1) and (2) calculations are repeated until coinsidence of e0 and e1. The obtained values of coefficients, displacements and loads are used in further calculations.
- Similar calculations are performed at other values of the damper clearances. The result is relation of the HD stiffness and damping by the clearance. This relation permits to determine the optimal damper clearance by optimal stiffness and damping obtained earlier in parametric studies.
- If the optimal values cannot be reached the HD dimensions (diameter and/or length) are to be changed. There is a chance to meet a situation when the displacement and load requirements cannot be fulfilled. In this ocasion the damper type is to be changed.
NOTE: Matching procedure can be used only for centralised dampers