Integrative design and processing of a conformal optical window pair in a cylindrical isolator

Ou, Yang; Dai, Yifan; Chen, Shanyong; Fan, Xiaoqiang; Hu, Hao; Xiong, Yupeng; Xiong, Bing; Du, Chunyang; Guan, Chaoliang

doi:10.1364/ao.459913

Cited by 5 publications

(2 citation statements)

References 15 publications

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“…17(a) in the Ref. 20, was used for the experiment, whose interferometric measurement result within the size of 84.89 mm×46.24 mm is shown in Fig. 17(b).…”

Section: Quasi-quantitative Schlieren Measurement Experimentsmentioning

confidence: 99%

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Design and simulation of a conformal optical window pair by the quasi-quantitative Schlieren measurement in a cylindrical isolator

Dai

Chen

et al. 2023

Opt. Eng.

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.To realize the quasi-quantitative Schlieren measurement of the shock train structure across the cylindrical isolator in the supersonic flow field, based on the theory of Schlieren measurement and light transmission, we propose the design scheme of conformal windows and discuss the machining feasibility with the window’s parameters. The relationship between the Schlieren imaging effect, the deflection of parallel light in the Schlieren apparatus, and the conformal optical window aberrations was researched, putting forward the optical simulation model of the conformal optical windows and the quasi-quantitative Schlieren measurement. Moreover, considering the actual wind tunnel test conditions, under the speed of Mach 2 at the isolator’s inlet, the distortion brought by conformal optical windows in the Schlieren observation region was simulated by the computational fluid dynamics method. Finally, the image correction algorithm for the distorted picture caused by the conformal windows was presented, and the quasi-quantitative Schlieren measurement through the conformal optical window pair was conducted for the experimental verification. The results reveal the quasi-quantitative Schlieren measurement effect across the high-precision conformal optical window pair of the cylindrical isolator, providing guidance on maintaining the balance between the manufacturing feasibility and the observation performance of conformal windows.

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“…17(a) in the Ref. 20, was used for the experiment, whose interferometric measurement result within the size of 84.89 mm×46.24 mm is shown in Fig. 17(b).…”

Section: Quasi-quantitative Schlieren Measurement Experimentsmentioning

confidence: 99%

“…Fig. 17(a) Cylindrical isolator with conformal optical windows and (b) interferometric measurement result 20. …”

mentioning

confidence: 99%

Design and simulation of a conformal optical window pair by the quasi-quantitative Schlieren measurement in a cylindrical isolator

Dai

Chen

et al. 2023

Opt. Eng.

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Ultra-precision milling and grinding for large-sagittal MgF2 aspheric optical elements

Wei,

Lei,

Fan

et al. 2023

Int J Adv Manuf Technol

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Ultra-precision machining for large-sagittal aspheric optical elements has become one of the research hotspots in the world's processing and manufacturing field in recent years. This paper mainly studies the processing of large-sagittal MgF2 aspheric optical components，analyzes the grinding tracks of two different grinding methods, and seeks the best grinding method. Experimental research was carried out on three milling modes in the rigid grinding process. In the processing method of pressed milling, the rotational speed of the workpiece has the most significant effect on the surface roughness. The surface roughness Ra can be reduced by reducing the grain size of the grinding wheel and adjusting the processing parameters. Through the cylindrical milling method, the surface roughness Ra measured with the D46 grinding wheel in the direction of rotation can reach the minimum, which is 0.7-0.8μm. In the fine grinding stage, the circumferential grinding and endface grinding models are established, and the simulation analysis and experimental verification of the trajectory of the abrasive particles in the two grinding methods are carried out. The comparison shows that with endface grinding, the surface of the component is removed evenly in both directions. When the grain size is 28μm, the surface roughness Ra∥ and Ra⊥ of face grinding are the smallest. Among them, Ra∥ is 0.0458 μm, and Ra⊥ is 0.0369 μm.This study is of great significance in improving the machining efficiency and accuracy of large-sagittal aspheric optical elements.

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Schlieren measurements of shock train flow fields in a supersonic cylindrical isolator at Mach 2

Ou,

Xiong,

Dai

et al. 2024

J Vis

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In a supersonic cylindrical isolator at Mach 2, the structures and frequency characteristics of shock train flow fields were experimentally studied by the schlieren measurement method. According to the design principle of parallel light through schlieren windows in a cylindrical duct, a high-precision conformal optical window pair was designed and integratively processed before. Based on a self-built pipeline structure with conformal windows in a direct-connect wind tunnel under adjustable back-pressure conditions, the shock surfaces in a cylindrical isolator at Mach 2 were first captured by the schlieren method. Then, the schlieren photographs were corrected by a nonlinear image transformation algorithm for the restoration of real shock train structures, and the experimental results were compared with numerical simulation results quantitatively. Finally, the shock train positions were calculated by an image recognition algorithm to analyze the self-excited oscillation frequency characteristics of shock train structures. The methods and experiments in this study enriched optical observation methods of supersonic flows through non-rectangular cross-section isolators in scramjet. Graphical abstract

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Integrative design and processing of a conformal optical window pair in a cylindrical isolator

Cited by 5 publications

References 15 publications

Design and simulation of a conformal optical window pair by the quasi-quantitative Schlieren measurement in a cylindrical isolator

Design and simulation of a conformal optical window pair by the quasi-quantitative Schlieren measurement in a cylindrical isolator

Ultra-precision milling and grinding for large-sagittal MgF2 aspheric optical elements

Schlieren measurements of shock train flow fields in a supersonic cylindrical isolator at Mach 2

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