Large-eddy simulations were used to investigate turbulent temperature fluctuations and turbulent heat flux in hot jets. A high-resolution finite difference Navier–Stokes solver was used to compute the flow from a 2 in. round nozzle. Three different flow conditions of varying jet Mach numbers and temperature ratios were examined. The large-eddy simulation results showed that the temperature field behaved similarly to the velocity field but with a more rapidly spreading mixing layer. Predictions of the mean u ¯ i and fluctuating u i velocities were compared to particle image velocimetry data. Predictions of the mean T ¯ and fluctuating T temperatures were compared to data obtained using Rayleigh scattering and Raman spectroscopy. Very good agreement with experimental data was demonstrated for the mean and fluctuating velocities. The large-eddy simulation correctly predicted the behavior of the turbulent temperature field but overpredicted the levels of the fluctuations. The turbulent heat flux was examined and compared to the Reynolds-averaged Navier–Stokes results. The large-eddy simulation and Reynolds-averaged Navier–Stokes simulations produced very similar results for the radial heat flux. However, the axial heat flux obtained from the large-eddy simulation differed significantly from the Reynolds-averaged Navier–Stokes result in both structure and magnitude, indicating that the Reynolds-averaged Navier–Stokes model was inadequate. Finally, the large-eddy simulation data were used to compute the turbulent Prandtl number and verify that a constant value of 0.7, which is typically used in the Reynolds-averaged Navier–Stokes models, was a reasonable assumption.


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    Title :

    Prediction of Turbulent Temperature Fluctuations in Hot Jets


    Contributors:

    Published in:

    AIAA Journal ; 56 , 8 ; 3097-3111


    Publication date :

    2018-08-01




    Type of media :

    Conference paper , Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English





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