Effects of tip injection on the performance and near wake characteristics of a model wind turbine rotor

2016-04-01
Abdulrahim, Anas
Anik, Ezgi
Ostovan, Yashar
Uzol, Oğuz
This paper presents an investigation of the effects of tip injection on the performance and near wake characteristics of a model wind turbine rotor. Experiments are conducted by placing a three-bladed horizontal axis wind turbine rotor at the exit of an open-jet wind tunnel. The rotor blades are non linearly twisted and tapered with NREL 5826 airfoil profile. The nacelle, hub and the blades are specifically designed to allow pressurized air to pass through and get injected from the blade tips while the rotor is rotating. Measurements of torque and thrust coefficient variations with the Tip Speed Ratio (TSR) as well as wake flow field surveys using Constant Temperature Anemometry are performed with and without tip injection. Results show that power and thrust coefficients both increase due to injection especially at TSR values higher than 3.5. Wake characteristics show a tip flow region that is radially pushed outwards with increased levels of turbulence occupying wider areas compared to the no injection case. Up to two diameters downstream within the wake, the boundary between the wake and the freestream, which is normally dominated by the presence of the tip vortices, gets more diffused and turbulence levels are significantly increased due to tip injection.
RENEWABLE ENERGY

Suggestions

Effects of camberwise varying tip injection on loss and wake characteristics of a low pressure turbine blade
Mercan, Bayram; Dogan, Eda; Ostovan, Yashar; Uzol, Oğuz (2015-08-01)
This paper presents the results of an experimental study that investigates the effects of camberwise varying tip injection on the total pressure loss and wake flow characteristics downstream of a row of Low Pressure Turbine (LPT) blades. This injection technique involves spanwise jets at the tip that are issued from a series of holes distributed along the camber line. The injection from each hole is individually and separately controlled using a computer driven solenoid valve and therefore the flow injectio...
Effects of mie vanes and tip injection on the performance and wake characteristics of HAWT
Anik, Ezgi; Abdulrahim, Anas; Uzol, Oğuz (null; 2016-01-08)
This paper presents the results of an experimental study that focuses on the tip leakage/vortex control of a model horizontal axis wind turbine rotor. The effects of Mie vanes and tip injection on the performance and wake characteristics of a model horizontal axis wind turbine rotor are investigated through experiments that are conducted by placing a specially designed three-bladed horizontal axis wind turbine rotor at the exit of an open-jet wind tunnel facility. The rotor blades are non-linearly twisted a...
Effect of steady and transient wind shear on the wake structure and performance of a horizontal axis wind turbine rotor
SEZER UZOL, NİLAY; Uzol, Oğuz (2013-01-01)
This paper presents an investigation of the effect of steady and transient free-stream wind shear on the wake structure and performance characteristics of a horizontal axis wind turbine rotor. A new three-dimensional unsteady vortex-panel method potential flow solver based on a free-vortex wake methodology, AeroSIM+, is used for this purpose. The code is validated using the experimental data from the National Renewable Energy Laboratory Unsteady Aerodynamics Experiments. The effects of vortex core model, co...
Effect of Turbine Blade Tip Cooling Configuration on Tip Leakage Flow and Heat Transfer
Sakaoğlu, Sergen; Kahveci, Harika Senem (2019-06-21)
The pressure difference between suction and pressure sides of a turbine blade leads to the so-called phenomenon, the tip leakage flow, which most adversely affects the first-stage high-pressure (HP) turbine blade tip aerodynamics. In modern gas turbines, HP turbine blade tips are also exposed to extreme thermal conditions requiring the use of tip cooling. If the coolant jet directed into the blade tip gap cannot counter the leakage flow, it will simply add up to the pressure losses due to this leakage flow....
Effect of cavity depth on thermal performance of a cooled blade tip under rotation
Sakaoglu, Sergen; Kahveci, Harika Senem (2019-11-01)
In this paper, the effect of cavity geometry of a squealer blade tip on its thermal performance is investigated. Numerical analyses were performed for three depth-to-width ratios for a cooled squealer tip. Also investigated is the effect of cooling introduction into the flow tip and the effect of rotation via the comparison of stationary and rotational domains where the latter was simulated by rotating the blade. The rotational speed and boundary conditions used in the numerical study are chosen to represen...
Citation Formats
A. Abdulrahim, E. Anik, Y. Ostovan, and O. Uzol, “Effects of tip injection on the performance and near wake characteristics of a model wind turbine rotor,” RENEWABLE ENERGY, pp. 73–82, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/33329.