The problem of dynamics for rotors on gas-dynamic, or airfoil bearings is nonlinear – it can be solved in a linearized formulation. It takes into account the change of stiffness and damping characteristics according to the rotor operating modes. It is divided into the following main sub-problems:
- Selection of the gas dynamic bearing template.
- Definition of bearing geometry and input data.
- Calculation of the static and dynamic bearing performance.
- Transfer of the calculated stiffness and damping coefficients to the rotor model.
- Calculation of the dynamic system natural frequencies.
- Critical speeds calculation.
- Determination of the stability limits.
- Calculation of violated vibrations.
Calculation of the airfoil, or gas-dynamic plain bearing is split into the following range of sub-problems:
- Calculation of the static gas pressure on shaft and petal walls;
- Calculation of gas bump foil bearing;
- Determination of the rotor static balance in the field of external static force, weight force, at a constant speed;
- Calculation of stiffness and damping coefficients.
The [DynFB] module determines the stability limits of the rotor, critical speeds, amplitude-frequency characteristics and others.
