Optical and thermal effects of a species-mismatched supersonic mixing layer formed over a cooled optical window

Aaron Fassler; Sergey Leonov; Stanislav Gordeyev

doi:10.1117/12.3027742

4 October 2024 Optical and thermal effects of a species-mismatched supersonic mixing layer formed over a cooled optical window

Aaron Fassler, Sergey Leonov, Stanislav Gordeyev

Author Affiliations +

Proceedings Volume 13149, Unconventional Imaging, Sensing, and Adaptive Optics 2024; 131490B (2024) https://doi.org/10.1117/12.3027742
Event: Optical Engineering + Applications, 2024, San Diego, California, United States

Abstract

The aero-optical distortions caused by supersonic mixing layers over a flat optical window are relevant to the performance of hypersonic vehicles. Such mixing layers are typically temperature-mismatched and gas speciesmismatched due to a need to efficiently cool the optical window. To investigate the effect of the mismatched properties across the mixing layer created by blowing a cool gas over a flat window, optical measurements of an M=2 freestream air flow with a cooling two-dimensional gas jet were taken using time-resolved Shack-Hartmann WFS and Schlieren photography. To complement the optical measurements, other non-intrusive techniques, specifically acetone-based PLIF and spatially-resolved infrared thermography techniques were implemented to extract relevant fluidic properties of the mixing layer. The cooling jet gas species were air, helium and carbon dioxide (CO2). To create the temperature mismatch, the total temperature of the freestream flow was varied from 295K to 750K, while the total temperature of the cooling jet was kept constant at 295K. Results of this experimental work will be presented and discussed. Based on experimental input, a scaling method proposed in previous work was implemented in order to predict aero-optical distortions, using the mixing-dominant assumption previously applied to the helium-air and air-CO2 case.

Conference Presentation

Citation Download Citation

Aaron Fassler, Sergey Leonov, and Stanislav Gordeyev "Optical and thermal effects of a species-mismatched supersonic mixing layer formed over a cooled optical window", Proc. SPIE 13149, Unconventional Imaging, Sensing, and Adaptive Optics 2024, 131490B (4 October 2024); https://doi.org/10.1117/12.3027742

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