Pulsed flow has been shown to enhance heat transfer coefficients of impinging jets. This paper considers the use of pulsed impinging jets, derived from a self-excited fluidic oscillator, for gas turbine cooling. Self-excited oscillatory behavior was demonstrated in simulations over a wide range of inlet to outlet pressure ratios from p 01 / p 2 = 1.0025 to p 01 / p 2 = 2.18 for a device with a nozzle throat to splitter length of 10.4 mm. Heat transfer simulations at two test points (460 and 769 Hz) resulted in Nusselt number enhancement of 13 and 15% over corresponding cases with nonperiodic flow at the same time-mean mass flow rate. Increased oscillation frequency was found to increase Nusselt number enhancement. In the range 10 < f < 20    kHz ( 0.04 < f L / v < 0.08 ), the Nusselt number approximately doubled. A computational geometry optimization study was performed to increase oscillation frequency, resulting in a 30% increase. Validation experiments were performed using thin-film gauge (high-frequency) and calorimeter (low-frequency) measurement techniques. Experimental results were broadly in line with numerical results; a Nusselt number enhancement of approximately 20% ( 186 < f < 322    Hz ) was achieved. Despite the enhancement in heat transfer, the fluidic oscillator is far from an ideal solution due to extreme pressure losses inside the device.


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    Title :

    Self-Excited Fluidic Oscillators for Gas Turbines Cooling Enhancement: Experimental and Computational Study


    Contributors:
    Ten, J. S. (author) / Povey, T. (author)

    Published in:

    Publication date :

    2018-11-26


    Size :

    12 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




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