The gap size effect on leakage flow and cavitation in the clearance of a 2D hydrofoil: high-speed visualization and velocity measurements

29th IAHR Symposium on Hydraulic Machinery and Systems

Pervunin, Konstantin S.^1 ; Timoshevskiy, Mikhail V.^1 ; Zapryagaev, Ivan I.^1 ; Markovich, Dmitriy M.^1^2^3 ; Semenov, Georgy A.^4 ; Zakharov, Aleksandr V.^4

Kutateladze Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, 1, Lavrentyev Ave., Novosibirsk

630090, Russia^1

Department of Physics, Novosibirsk State University, 2, Pirogov Str., Novosibirsk

630090, Russia^2

Institute of Power Engineering, Tomsk Polytechnic University, 30, Lenin Ave., Tomsk

634050, Russia^3

Public Joint-Stock Company Power Machines (LMZ), 3A, Vatutin Str., Saint-Petersburg

195009, Russia^4

关键词: Attack angle;    Cavitation inception;    Cavitation number;    Flow condition;    Gap cavitation;    High-speed visualization;    Leakage flow;    Tip clearance;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/240/6/062040/pdf
DOI  :  10.1088/1755-1315/240/6/062040

来源: IOP

【 摘 要 】

In the study, tip-clearance cavitation inception and development was studied in the gap between an end face of a NACA0022-34 hydrofoil and a transparent sidewall of a test channel. The experiments were carried out for the attack angles of 3° and 9° and the gap width of 0.4 to 0.8 mm under various flow conditions on the cavitation number. In order to observe the tip-clearance cavitation inception and its dynamics, a high-speed visualization was applied. The leakage flow velocity was measured inside the clearance by a modified PTV technique. It was shown that unsteady dynamics of the primary cavity on the foil suction side affects the leakage flow direction and the gap cavitation evolution. An increase of the gap width causes the gap cavitation to be initiated at higher cavitation numbers.