Blade-Tip Vortex Detection in Maneuvering Flight Using the Background-Oriented Schlieren Technique

The tip leakage flow affects turbomachines performance generating losses and reducing the effective blading; in addition, unsteady phenomena arise, negatively influencing the machine stability. In this paper, an overview of the existing models is presented. Local measurements of the pressure pulsations, visual flow observations and high quality video recordings from a high speed camera are performed in a novel pump laboratory, which provides the desired visualization of the rotating channels, and allows to study the fluctuating and intermittent nature of this phenomenon, and detect any asymmetry among the channels. A detailed comparison of the vortex tip structure for various tip clearances and with a whole set of numerical simulations finally completes the analysis. The three main focus areas are: tip vortex location, structure and evolution, performance comparison between shrouded and open impeller, at different tip clearance sizes, and study of the rotating instabilities.

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Numerical investigation of blade-tip-vortex dynamics

CEAS Aeronautical Journal ◽

10.1007/s13272-018-0287-2 ◽

2018 ◽

Vol 9 (3) ◽

pp. 373-386 ◽

Cited By ~ 1

Author(s):

Kurt Kaufmann ◽

C. Christian Wolf ◽

Christoph B. Merz ◽

Anthony D. Gardner

Keyword(s):

Numerical Investigation ◽

Vortex Dynamics ◽

Tip Vortex ◽

Blade Tip

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Semi in-Situ Measurement of Zincate Ion Concentration Near Zinc Anode Using Background-Oriented Schlieren Technique

ECS Meeting Abstracts ◽

10.1149/ma2020-02453755mtgabs ◽

2020 ◽

Vol MA2020-02 (45) ◽

pp. 3755-3755

Author(s):

Yasumasa Ito ◽

Xiao Liang ◽

Yasuhiko Sakai ◽

Koji Iwano

Keyword(s):

In Situ Measurement ◽

Ion Concentration ◽

Zinc Anode ◽

Schlieren Technique ◽

Background Oriented Schlieren

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Near Wake Regime Study on Wind Turbine Blade Tip Vortex

Volume 2: Combustion, Fuels, and Emissions; Renewable Energy: Solar and Wind; Inlets and Exhausts; Emerging Technologies: Hybrid Electric Propulsion and Alternate Power Generation; GT Operation and Maintenance; Materials and Manufacturing (Including Coatings, Composites, CMCs, Additive Manufacturing); Analytics and Digital Solutions for Gas Turbines/Rotating Machinery ◽

10.1115/gtindia2019-2493 ◽

2019 ◽

Author(s):

Ojing Siram ◽

Niranjan Sahoo

Keyword(s):

Wind Turbine ◽

Strouhal Number ◽

Vortex Shedding ◽

Flow Condition ◽

Pitch Angle ◽

Tip Vortex ◽

Near Wake ◽

Helical Vortex ◽

Blade Tip ◽

Blade Pitch Angle

Abstract In the present research article results on wind turbine blade tip vortex have been presented, the measurements have been done behind a model scale of horizontal axis wind turbine rotor. The rotor used for flow characterization is a three-bladed having NACA0012 cross-section, the study has been performed for low range tip speed ratio of 0–2 and wind speeds range of 3–6 m/s. The investigation has been conducted specifically to near wake regime, which is often expressed as the region of regular helical vortex structures. Although this nature of regular helical vortex pattern has always been a question of debate with respect to changes in the flow condition, rotor geometry and point of measurements. A systematic experiment was done mainly on the frequency of vortex shedding through hot-wire anemometry (HWA), and the corresponding frequency is express in terms of Strouhal number. Present article work within near wake regime includes tip vortex shedding stability analysis for different blade pitch angle and flow condition. From the systematic experimental observation, the evaluated data indicate that the Strouhal number has an incremental trend when the blade pitch angle is close to 40°, and above it inconsistency in frequency response is observed.

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