Fig. 1. Helicopter model

Fig. 2. The main rotor and tail rotor size and their direction of rotation

Fig. 3. （a） Schematic diagram of the position of engine casing and infrared suppressor；（b） Engine casing model; （c） Infrared suppressor with mult-nozzles ejector

Fig. 4. Schematic diagram of the computational domain

Fig. 5. （a） Comparison of main rotor downwash velocity distribution; （b） Comparison of tail rotor flow velocity distribution

Fig. 6. Schematic diagram of computational grids

Fig. 7. Schematic diagram of solar irradiation angle at different times

Fig. 8. Schematic diagram of solar irradiation angle at different seasons

Fig. 9. Schematic diagram of solar irradiation angle under different flight directions of helicopter

Fig. 10. （a） Horizontal detection plane; （b） Transverse detection plane; （c） Longitudinal detection plane

Fig. 11. Streamlines of helicopter. (a) Side view; (b) Top view; (c) Rear view

Fig. 12. Temperature cloud of helicopter fuselage skin at different times (top view)

Fig. 13. Temperature cloud of helicopter fuselage skin at different seasons (top view)

Fig. 14. Infrared radiation intensity of 8-14 μm band on each detection plane at different times. (a) Horizontal detection plane; (b) Transverse detection plane; (c) Longitudinal detection plane

Fig. 15. Distribution diagram of infrared radiation intensity in the 8-14 μm band throughout the day at specific detection points; （b） Distribution diagram of dimensionless infrared radiation intensity throughout the day at specific detection points

Fig. 16. Infrared radiation intensity of 8-14 μm band on each detection plane at different seasons. (a) Horizontal detection plane; (b) Transverse detection plane; (c) Longitudinal detection plane

Fig. 17. Infrared radiation intensity of 8-14 μm band on each detection plane under different flight directions of helicopter. (a) Horizontal detection plane; (b) Transverse detection plane; (c) Longitudinal detection plane