Your Topic

In modern turbomachinery, shaft vibrations caused by fluid film forces and moments in annular seals often limit performance and reliability. Consequently, this narrow fluid filled annuli play a crucial role in the overall system behavior. The dynamic characteristics of such narrow gaps like journal bearings and annular seals significantly influence the turbomachinery’s response. These characteristics are commonly represented by classical mechanical components springs, dampers, and masses which enable their characterization through the rotordynamic coefficients of stiffness, damping, and inertia. While the stiffness coefficients have been determined through a completed static CFD analysis utilizing a fully developed 360° mesh with eccentricity and tilt, the remaining task is to determine the damping and inertia coefficients. This requires dynamic simulations with prescribed rotor motion to capture velocity and acceleration dependent hydrodynamic forces.

Your Task

The aim of this thesis is to determine the damping and inertia coefficients of narrow annular gaps in turbomachinery by conducting CFD simulations. To achieve this, a moving mesh framework must be developed and implemented within the CFD environment, allowing prescribed rotor motions to be simulated. The Master's thesis includes the following tasks:

• familiarization with the topic and development of the moving mesh setup for dynamic CFD simulations
• setting up and running the simulations in OpenFOAM
• compare the numerical results with experimental results from the gap flow test rig @FST and validate the inhouse 2D tool.
• documentation of the results

Your Benefit

• Close collaboration within the team as well as with other students and the supervisors
• Insight into a fundamental research topic with a variety of technical applications
• Development of essential skills such as scientific presentation, data visualization, and technical documentation.

The scope of the tasks will be tailored to your preferences, with flexibility for partial remote work.

I look forward to hearing from you by e-mail or in person!