Response of a Rotor Under the Influence of Seal Forces
Application ID: 102621
The fluid flow in seals causes a strong restoring radial force, opposing the shaft motion. Also, there is a cross-coupled force due to the axial variation of the circumferential flow. The first type of force always has a stabilizing effect on the rotor, whereas the second one can cause an instability under certain conditions.
In this example, an axial compressor is modeled using the Beam Rotor interface. The compressor has 10 impeller stages, with a seal near each impeller to prevent leakage. In addition, a balance piston seal is located at the end of the impeller stages. The time-dependent response of the system is studied for a gradually increasing rotor speed. Two cases are considered for the simulation: one without seals and one with seals. The responses of the system for the two cases are compared. The result show improved stability when the seals are included.
This model example illustrates applications of this type that would nominally be built using the following products:
however, additional products may be required to completely define and model it. Furthermore, this example may also be defined and modeled using components from the following product combinations:
The combination of COMSOL® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part libraries. Particular functionality may be common to several products. To determine the right combination of products for your modeling needs, review the Specification Chart and make use of a free evaluation license. The COMSOL Sales and Support teams are available for answering any questions you may have regarding this.
