The effects of tip-gap size on the tip-leakage vortical structures and velocity and pressure fields are investigated using large-eddy simulation, with the objective of providing guidelines for controlling tip-leakage cavitation and viscous losses associated with the tip-leakage flow. The effects of tip-gap size on the generation and evolution of the end-wall vortical structures are discussed by...

The tip-clearance flow in axial turbomachines is studied using large-eddy simulation with particular emphasis on understanding the unsteady characteristics of the tip-leakage vortical structures and the underlying mechanisms for cavitation-inducing low-pressure fluctuations. Systematic and detailed analysis of the velocity and pressure fields has been made in a linear cascade with a moving end-...

The paper presents a design procedure for anti-vortex endplates that are fitted to tip limited blades of the subsonic axial fans utilised in compact cooling units. The authors study the impact of tip leakage vortex bursting on the performance of the studied class of fans. The vortex breakdown occurs in the swirling flows at a blade’s tip, and is found to be a flow feature associated with the pr...

In the framework of this master thesis, a numerical study has been carried out in order to investigate the effect of tip geometry on the tip leakage flow and heat transfer features in a unshrouded high pressure axial flow turbine stage designed by Erhard [10]. Four different tip profiles were considered, namely a default flat tip, a modified flat tip, a modified double squealer tip and a modifi...

The tip-clearance flow in axial turbomachines is studied using large-eddy simulation with particular emphasis on understanding the underlying mechanisms for viscous losses in the end-wall region and the unsteady characteristics of the tipleakage vortical structures. Systematic and detailed analysis of the mean flow field and turbulence statistics has been made in a linear cascade with a moving ...

An experimental and numerical investigation into the tip leakage flow of a turbine rotor is carried out using a particle image velocimetry (PIV) system and the commercial software ANSYS CFX 14.0. The specimen used in this work is a typical GE-E3 model with a new squealer tip design. The experimental data are used to create a turbulence model and numerical strategy. Through the validated turbule...

The energy performance and radial force of a mixed flow pump with symmetrical and unsymmetrical tip clearance are investigated in this paper. As the tip clearance increases, the pump head and efficiency both decrease. The center of the radial force on the principal axis is located at the coordinate origin when the tip clearance is symmetrical, and moves to the third quadrant when the tip cleara...

A large-eddy simulation (LES) solver which combines an immersed-boundary technique with a curvilinear structured grid has been developed to study the temporal and spatial dynamics of a rotor tip-clearance flow, with the objective of determining the underlying mechanisms for low pressure fluctuations downstream of the rotor near the endwall. Salient feature of the numerical methodology, includin...