The effect of the clearance geometries on the cavitating vortices near the foil tip

Asian Working Group- IAHR's Symposium on Hydraulic Machinery and Systems

Guo, Q.^1,2 ; Huang, X.B.^1 ; Yang, F.^1 ; Qiu, B.Y.^1

School of Hydraulic Energy and Power Engineering, Yangzhou University, Yangzhou

225127, China^1

College of Water Resources and Civil Engineering, China Agricultural University, Beijing

100083, China^2

关键词: Axial flow rotor;    Blade tip clearance;    Cavitation characteristics;    Cavitation model;    Cavitation phenomenon;    Geometrical conditions;    Vortex cavitation;    Vortex structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/163/1/012018/pdf
DOI  :  10.1088/1755-1315/163/1/012018

来源: IOP

【 摘 要 】

The blade tip clearance is inevitable for an axial flow rotor. The clearance flow contains various vortices and the resulting vortex cavitation is a concern in hydraulic machineries. In the narrow gap, the vortex features are sensitive to the change of the clearance size, and then the geometry factors may influence the vortex cavitation characteristics. As a simplification of a blade, an isolated hydrofoil is convenient for adjusting the clearance geometries in different cases. The effects of the clearance shape, gap height and gap width on the cavitating vortices are discussed in present paper. As the limited space and the cavitation phenomenon make it difficult to measure the vortex flow features, the numerical simulation is widely used to investigate the cavitating vortices. An improved cavitation model, which is suitable for the vortex cavitation, is used in present work. Under the different geometrical conditions, the vortex structures, the pressure features and the cavitation characteristics are revealed from the simulation.