Numerical Analysis of Sealing Performance of Supercritical CO2 in Turbine Shafts Using Hybrid Labyrinth– Honeycomb Seals With Seal Structures

Leakage in turbomachinery significantly reduces system efficiency, with labyrinth seals playing a critical role in minimizing fluid or gas leakage. This research focuses on improving sealing technology by developing a new seal design that uses supercritical CO2 (sCO2) as the sealing fluid and a honeycomb structure inspired by gas turbine applications, which can operate under high pressures and temperatures. To optimize the seal to operate under these conditions, the dimensions are chosen according to proven gas turbine designs scaled to meet sCO2 design parameters and iterated over multiple simulations to recommend appropriate dimension ranges. A typical honeycomb structure is a proven method for sealing for gas turbine applications to both minimize leakage and manipulate the pressure of the flow. This study includes a detailed numerical study of how this honeycomb structure performs as a seal in an sCO2 cycle. To test and validate the design, Computational Fluid Dynamics (CFD) simulations were conducted using ANSYS under both static and dynamic conditions. Using CFD provides key insights into the structure's mass flow rate to better understand this design's impact through vortex formations and the efficiency of this seal. The honeycomb is fixed to the stator, while the rotor moves freely, creating a vortex flow in two directions, leading to a pressure difference and forming a strong boundary layer due to this flow pattern. Identifying the validity of a honeycomb structure will provide additional recommended labyrinth seal designs for future consideration