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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2019 Vol.20 No.6 P.458-474
Calculation and experimental verification of radiation characteristics of spontaneous chaff clouds in high-speed flows
Abstract: When spontaneous chaffs diffuse in air, numerous radiations are shielded, absorbed, and reflected between chaffs, and there is interaction between the chaffs and the air. This makes it relatively complicated to calculate radiation transmission. To calculate the spatial distribution and generate radiation images of spontaneous chaffs, a radiation calculation model based on reverse path sampling was constructed which takes account of the transmission characteristics of radiation. This model hypothesizes that all detectors transmit light outward uniformly in the opposite direction of the radiation. After sampling statistics of light routes, the number and intensity of lights received by detectors along the radiation path were calculated. Next, a spontaneous combustion model of chaff was constructed. In this model, the effects of the porous structure of the chaff surface on the combustion rate of reactive metals are considered. The accuracy of this model was proved by comparing calculated results with experimental data. Finally, the spatial distribution of chaff clouds was calculated and their radiation images obtained. The results from the constructed model proved to be highly accurate when compared with measurement data from an experimental rocket sled.
Key words: Chaff clouds; Radiation calculation; Special radiance characteristics; Reactive metals; Spontaneous combustion
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DOI:
10.1631/jzus.A1900020
CLC number:
TJ761.1
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On-line Access:
2024-08-27
Received:
2023-10-17
Revision Accepted:
2024-05-08
Crosschecked:
2019-05-08