Fig. 1. Transmission path of exhaust plume infrared radiation
Fig. 2. Simulation calculation flow of exhaust plume infrared radiation intensity based on ray tracing
Fig. 3. Simulation calculation result of exhaust plume temperature field
Fig. 4. Geometric relationship of air-based detection scene
Fig. 5. Line of sight detection angle and detection range
Fig. 6. Variation curve of radiation attenuation characteristics of particle with complex refractive index. (a) Variation curve of the scattering cross section with the real part of the complex refractive index; (b) variation curve of the absorption cross section with the imaginary part of the complex refractive index
Fig. 7. Variation curve of particle extinction cross section with particle diameter
Fig. 8. Variation curve of particle scattering characteristics with particle diameter. (a) Variation curve of asymmetry factor with particle diameter; (b) variation of scattering phase function with asymmetry factor
Fig. 9. Infrared radiation suppression rate with different particle diameters. (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 10. Infrared simulation images of exhaust plumes with different particle diameters. (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 11. Infrared radiation suppression rate of different particle flow rates (diameter is 3 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 12. Infrared radiation suppression rate of different particle flow rates (diameter is 10 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 13. Infrared simulation images of exhaust plumes with different particle flow rates (diameter is 3 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 14. Infrared simulation images of exhaust plumes with different particle flow rates (diameter is 10 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 15. Infrared radiation suppression rate with different particle complex refractive indexes (diameter is 3 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 16. Infrared radiation suppression rate with different particle complex refractive indexes (diameter is 10 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 17. Infrared simulation images of exhaust plumes with different particle complex refractive indexes (diameter is 3 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 18. Infrared simulation images of exhaust plumes with different particle complex refractive indexes (diameter is 10 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 19. Spectral radiation intensity with different particle complex refractive indexes (diameter is 3 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Fig. 20. Spectral radiation intensity with different particle complex refractive indexes (diameter is 10 μm). (a) Short waveband; (b) medium waveband; (c) long waveband
Parameter name | Parameter value |
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Atmospheric pressure /Pa | 3×104 | Atmospheric temperature /K | 255 | Atmospheric composition model | ideal atmosphere model of Fluent | Short-waveband light radiance /[W·(sr·m2)-1] | 10 | Short-waveband light direction | -Z axis | Flight height /km | 10 | Flight speed /Ma | 1.0 | Turbulence model | realizable K-epsilon | Inlet air flow rate /(m·s-1) | 400 | Inlet air pressure /Pa | 2×105 | Inlet air temperature /K | 650 | Fuel type | C5H12 | Inlet fuel temperature /K | 300 | Inlet fuel flow rate /(kg·s-1) | 0.15 | Particle flow rate | variable | Particle diameter | variable |
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Table 1. Simulation parameters of exhaust plume flow field
Experiment name | Particle diameter /μm | Particle flow /(kg·s-1) | Particle complex refractive index |
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Particle diameter experiment | 3、5、10、20 | 1.0 | 2+0i | Particle flow experiment | 3、10 | 0.02、0.2、0.5、1.0、2.0 | 2+0i | Particle complex refractive index experiment | 3、10 | 2.0 | 2+0i、2+5×10-5i、2+5×10-3i、2+0.5i、2+5i、2+25i、2+100i |
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Table 2. Simulation experiment scheme of solid particle radiation suppression rate