Active Flow Control of Sprays with Synthetic Jets

Aerofoil active flow control has been attempted to increase the permissible loading of boundary layers in gas turbine components. Steady suction and blowing, pulsing and synthetic jets are all means to remove low energy flow, replace momentum deficits, or promote mixing to inhibit boundary layer separation. A curved surface near the trailing edge (“Coanda surface”) is another technique used to control aerofoil boundary layer separation. This paper presents the design of a stator with active flow control for a high speed compressor using a Coanda surface. The Coanda surface is located behind an injection slot on the aerofoil suction side of the first stage of a four-stage high speed research compressor. The design method and the present results are based on steady numerical calculations. The design intent is to reduce the number of vanes. This active flow control is used to maintain the flow exit angle of the reference stator despite the resulting increase in stator loading. It is shown that the solidity of the flow-controlled stator can be decreased by 25% with a blowing rate of 0.5% of the main mass flow.

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Comparison between synthetic jets and continuous jets for active flow control: Application on a NACA 0015 and a compressor stator cascade

Aerospace Science and Technology ◽

10.1016/j.ast.2015.03.004 ◽

2015 ◽

Vol 43 ◽

pp. 256-280 ◽

Cited By ~ 52

Author(s):

M.G. De Giorgi ◽

C.G. De Luca ◽

A. Ficarella ◽

F. Marra

Keyword(s):

Flow Control ◽

Active Flow Control ◽

Synthetic Jets ◽

Control Application ◽

Naca 0015 ◽

Active Flow

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Numerical simulations of active flow control with synthetic jets in a Darrieus turbine

Renewable Energy ◽

10.1016/j.renene.2017.05.075 ◽

2017 ◽

Vol 113 ◽

pp. 129-140 ◽

Cited By ~ 27

Author(s):

D. Velasco ◽

O. López Mejia ◽

S. Laín

Keyword(s):

Flow Control ◽

Numerical Simulations ◽

Active Flow Control ◽

Synthetic Jets ◽

Active Flow

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Numerical Simulation of a Low Pressure Turbine Blade Employing Active Flow Control

Volume 2: Fora ◽

10.1115/fedsm2006-98566 ◽

2006 ◽

Author(s):

Marshall C. Galbraith ◽

Amit Kasliwal ◽

Kirti Ghia ◽

Urmila Ghia

Keyword(s):

Boundary Layer ◽

Flow Control ◽

Turbine Blade ◽

Cfd Simulation ◽

Control Method ◽

Active Flow Control ◽

Low Pressure ◽

Synthetic Jets ◽

Low Pressure Turbine ◽

Active Flow

High altitude aircraft experience a large drop in the Reynolds number (Re) from take off conditions to cruise conditions. It has been shown in previous research performed by Simon and Volino [1] that this reduction in Re number causes the flow inside the turbine cascades to become laminar, and separate more readily on the suction side of the turbine blade. This boundary-layer separation greatly reduces the efficiency of the turbine and aircraft engine as a whole, and therefore is undesirable. To prevent this loss of efficiency, research will be pursued for active and passive means to delay and/or eliminate the flow separation. Lake et al. [2] used passive boundary layer trip, dimples, and V-grooves in an extensive study to reduce separation on the Pak-B turbine blade. Although these passive techniques were able to reduce the separation at fixed Re numbers, an active flow control method is needed for more efficient separation reduction over a range of Re numbers. Currently, researchers are investigating several different active flow control devices, including pulsating synthetic jets, vortex generator jets (VGJ), and moving protuberances. The proposed study intends to further investigate the mechanism of flow control via synthetic jets, which alternate between suction and blowing, on a low pressure turbine blade utilizing a Large Eddy Simulation (LES) Computational Fluid Dynamics (CFD) solver. Optimum values of the associated parameters such as jet angle, blowing ratio, frequency, duty cycle, etc., of the synthetic jets will be determined. However, before investigation of the effectiveness of synthetic jets, the CFD simulation will be validated with experimental data on VGJ. A description of the implementation is presented along with preliminary results.

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