Experimental Investigation on Aero-Optical Mitigation of Hypersonic Optical Dome Using Microvortex Generators

Ding, Haolin; Yi, Shihe; Zhao, Xianwei; Xiong, Haoxi; Ouyang, Tianci

doi:10.2514/1.j058084

Cited by 26 publications

(3 citation statements)

References 15 publications

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“…Multi-field-of-view technology, short-wave infrared band sensors, and optimized star catalogs have been used to improve navigation starlight capture under far-field brightness [10,11]. Ding et al believed that the image quality could be improved and the difficulty of wavefront adaptive correction could be reduced by appropriately extending the exposure time [12].…”

Section: Introductionmentioning

confidence: 99%

An Evaluation Model of Star Sensor Observation Capability Under Hypersonic Aerothermal Conditions

Chen

Zheng

et al. 2023

IEEE Access

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During hypersonic flight in the atmosphere, severe aerothermal effects occur on the optical hood or observation window of an aircraft, keeping the optical window and surface flow field in a hightemperature state, as well as causing a large amount of radiation and strong background noise. These phenomena have serious effects on the observation capability of star sensors. An evaluation model of star sensor observation capability under hypersonic aerothermal conditions was constructed in this study, using a definition of the signal-to-noise ratio considering defocused intense radiation sources. Furthermore, a method of calculating the observable limiting magnitude under aerothermal conditions is given. The model was used in simulation tests involving different flight states and temperature conditions. The results showed that the thermal radiation of the aircraft observation window has the greatest influence, which is more than two orders higher than that of the outer flow near the window; when the window temperature was controlled below 750 K, for a star sensor with an SNR threshold of 3, navigation stars with magnitudes brighter than 5 could be captured in the visible band of 0.35-0.7 μm, and the near-infrared band of 0.9-1.4 μm was unavailable.

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Section: Introductionmentioning

confidence: 99%

An Evaluation Model of Star Sensor Observation Capability Under Hypersonic Aerothermal Conditions

Chen

Zheng

et al. 2023

IEEE Access

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“…HfO 2 film on the surface of CVD zinc sulfide window and yttrium oxide film on the surface of the sapphire window can delay the saturation of the imaging device and improve the resistance of the optical hood to thermal radiation interference [14]. Window cooling methods mainly include external jet cooling and internal cooling, and the cooling airflow of the external cooling scheme mixes with the airflow within the original boundary layer to form a shear/mixed layer complex flow, which may affect the transmission of target light [15], [16]. Nevertheless, window cooling techniques can effectively improve the aero-optical thermal environment or reduce the window temperature, and are still most effective physical means to suppress the window thermal radiation effects [17], [18].…”

Section: Introductionmentioning

confidence: 99%

Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

Liu

Xiong

et al. 2023

IEEE Photonics J.

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When a high-speed aircraft flies in the atmosphere, the imaging window is subjected to airflow friction, the kinetic energy of the airflow is converted into thermal energy, which makes the surface temperature of the imaging window rise unevenly, the imaging quality is significantly reduced, called aerooptical thermal radiation effects. The continuously increasing nonuniform thermal radiation bias field is not conducive to the precise identification of the target. To remove the bias field in degraded infrared images, this paper proposes a progressive nonuniformity correction method. First, we establish a progressive thermal radiation effects correction model to estimate the thermal radiation bias field based on bilateral filtering and Bézier surface fitting. Then, to avoid overfitting the bias field, the degree of Bézier surface is reduced progressively during the iterative process. Finally, according to the properties of the heat transfer of the aero-optical thermal radiation effects, a gradient orientation prior is imposed for both the thermal radiation bias field and the latent clear image. experiments on simulated degraded images and real degraded IR images show that our method can reduce the thermal radiation effects residual compared with the current aero-optical thermal radiation effects correction methods. The code will be publicly available upon acceptance.

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“…The number of beams used and their spacing determine the spatial resolution of the Malley probe [8]. A background-oriented schlieren (BOS) achieves high spatiotemporal precision measurements by determining the flow field structure using the relationship between the density gradient field and the refractive index field and by obtaining the displacement of the light in two directions after passing through the flow field using a cross-correlation operation on the background lattice with or without flow field interference [9]. In addition to the abovementioned experimental methods, the nanotracer planar laser scattering (NPLS) technology developed by Professor Yi can realize the high-spatiotemporal-resolution visualization of time-dependent transient flow in a section of a three-dimensional complex flow field [10].…”

Section: Introductionmentioning

confidence: 99%

Simulation Test of The Aerodynamic Environment of A Missile-Borne Pulsed Laser Forward Detection System at High Flight Speed

Liu,

Li,

Hua

et al. 2023

Photonics

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When a missile-borne pulsed laser forward detection system flies at supersonic speed, the laser beam will be distorted by the uneven outflow field, resulting in a significant reduction in ranging accuracy. In this paper, the impact of high flight speed on a pulsed laser detection system is studied. First, a new ray tracing method with adaptive step size adjustment is proposed, which greatly improves the computational efficiency. Second, the aerodynamic environment of a munition flying at high speed is simulated by an intermittent transonic and supersonic wind tunnel to obtain the schlieren data of the flow field at various Mach numbers. The schlieren data present a shock wave structure similar to that of the simulation. In addition, the variation patterns of the pulsed laser echo waveform of the model under different aerodynamic conditions are studied to evaluate the detectability and operational stability of the laser detection system under static conditions. The test results match the simulation results well, and the two offer relatively consistent shock wave structures, which verifies the correctness and effectiveness of the flow field simulation model. The test echo waveforms are in good agreement with the simulated echo waveforms; the relative errors between the peak values of test and simulated echo waveforms at various Mach numbers do not exceed 20%, and the correlation coefficients between the test and simulated echo waveforms all exceed 0.7, indicating high correlations between the two.

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Experimental Investigation on Aero-Optical Mitigation of Hypersonic Optical Dome Using Microvortex Generators

Cited by 26 publications

References 15 publications

An Evaluation Model of Star Sensor Observation Capability Under Hypersonic Aerothermal Conditions

An Evaluation Model of Star Sensor Observation Capability Under Hypersonic Aerothermal Conditions

Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

Simulation Test of The Aerodynamic Environment of A Missile-Borne Pulsed Laser Forward Detection System at High Flight Speed

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