Infrared radiation (IR) characteristics are important parameters for detecting, identifying, and striking military targets in the context of systematic countermeasures. Accurate calculation of IR characteristics for aircraft is significant for the simulation of war situations and the designation of combat strategy. In this work, integrated IR characteristics of aircraft skin and exhaust plume and their interaction are investigated by considering the reflection based on a bi-directional reflectance distribution function and various influence factors such as solar irradiation, ground reflection, aerodynamic heating, and projection radiation from the background. Combined with infrared emission and reflection characteristics of the skin, omnidirectional IR intensity distributions of 3-5 μm and 8-14 μm at different Mach numbers are obtained. The exhaust plume IR characteristic for different waves and wavebands are also investigated by considering the presence or absence of base and the difference in nozzle inlet temperature. On this basis, integrated IR characteristics between the skin and exhaust plume are investigated. Results show that aircraft IR characteristics of 3-5 μm are concentrated in the exhaust plume and high-temperature skin near the exhaust plume, while the signals of 8-14 μm are concentrated in the skin. The research results are expected to supply guidance for better detection and identification of typical flight targets.
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http://dx.doi.org/10.3390/ma15217726 | DOI Listing |
Environ Sci Technol
November 2024
Wolfson Atmospheric Chemistry Laboratories, University of York, York YO10 5DD, United Kingdom.
We develop a new technique called where fast response instruments located at the roadside are used to measure exhaust plumes of passing vehicles. The approach is used to generate highly disaggregated vehicle emissions information by vehicle type, which compares well with traditional vehicle emission remote sensing. Additionally, the technique provides valuable new information on ambient concentration source apportionment by vehicle type.
View Article and Find Full Text PDFSci Total Environ
December 2024
Division of Environment and Sustainability, The Hong Kong University of Science and Technology,Hong Kong Special Administrative Region of China. Electronic address:
Sci Total Environ
December 2024
Environmental Department, Research Centre for Energy, Environment and Technology (CIEMAT), Spain.
Remote sensing techniques have emerged as valuable tools for characterizing pollutant emissions from large vehicle fleets and identifying high emitter single vehicles in real driving conditions. Nevertheless, the use of these systems for official emission control purposes by public administrations is an issue because the remote sensing devices must obtain official metrological certification, which currently lacks an international technical standard. The fluid dynamic study that we present demonstrates the promising potential of using pulsed synthetic reference plumes of known chemical composition in order to simulate exhaust emissions produced by combustion engine vehicles in a repetitive and controlled way.
View Article and Find Full Text PDFMaterials (Basel)
July 2024
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Aerosol infrared stealth technology is a highly effective method to reduce the intensity of infrared radiation by releasing aerosol particles around the hot exhaust plume. This paper uses a Computational Fluid Dynamics (CFD) two-phase flow model to simulate the exhaust plume fields of three kinds of engine nozzles containing aerosol particles. The Planck-weighted narrow spectral band gas model and the Reverse Monte Carlo method are used for infrared radiation transfer calculations to analyze the influencing factors and laws for the suppression of the infrared radiation properties of exhaust plumes by four typical aerosol particles.
View Article and Find Full Text PDFToxics
June 2024
Faculty of Engineering and Natural Sciences, Tampere University, FI-33720 Tampere, Finland.
International shipping's particulate matter primary emissions have a share in global anthropogenic emissions of between 3% and 4%. Ship emissions of volatile organic compounds (VOCs) can play an important role in the formation of fine particulate matter. Using an aerosol box model for the near-plume scale, this study investigated how the changing VOC emission factor (EF) for ship engines impacts the formation of secondary PM in ship exhaust plumes that were detected during a measurement campaign.
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