No abstract

Convective heat transfer in the cavity between two corotating disks is of great importance for turbomachinery applications. The complex three dimensional and unsteady flow structures induced by the Coriolis forces inside the cavity, and therefore the resulting heat transfer, are challenging to be measured in an experiment or predicted by simulation. In this paper a simplified cavity geometry, characterized experimentally by Long at al., has been chosen. The results obtained with a Very Large Eddy Simulation using Lattice-Boltzmann Method for two operating point with different rotation speeds are compared to the experimental heat transfer coefficients at the wall. The simulation results show the characteristic flow structures and behavior induced by the different regimes. A sensitivity analysis of the results is presented, both for numerical parameters such as grid resolution and for physical parameters, namely the throughflow velocity profile and shroud temperature.

This paper describes the experimental and numerical results of flow fields inside a rotor-stator rotating cavity. The rotational speeds and the axial throughflow are varied as experimental conditions. In the experiment, 3-components velocity vectors on the r–θ and r–z sections are obtained by a stereo dynamic PIV system to understand complex flow fields in detail such as flow structure and unsteadiness. A large eddy simulation (LES) is also carried out to confirm the analytical capability for the rotating cavity and to complement the understanding of the flow field. From the results, axisymmetric steady flow fields are observed under high Rossby number conditions, while several vortices are captured in the cavity in the r – θ section under low Rossby number conditions. The visualization results with seeding tracers for PIV show the flow structure of flow fields. LES can predict the flow field of the experimental result and the behavior of vortices which are varied as to the change of Ro conditions.

In this paper, in order to improve temperature prediction, 2D axisymmetric CFD analysis has been implemented to determine the cavity flow network in Finite Difference Method (FDM) thermal analysis model. With this work process, for example, the complex recirculation of cavity flow can be considered in FDM thermal analysis. In the beginning, the rig test of simplified cavity with rotating disk and PIV measurement are carried out to investigate the flow structure in the cavity and to validate CFD analysis. CFD result has matched well with the measurement data of PIV, and it has been found that SST k-ω turbulent model provides the most reliable result by the sensitivity study. The study result also helps to choose the most suitable scheme of discretization and the method of pressure correction. Then, the modeling of the cavity flow network based on CFD analysis result has been applied to the thermal analysis for the aero-engine. Compared with the measured data, the result with this modeling shows that temperature prediction has been well improved.

No abstract