Abstract: Numerical simulations are conducted to analyze the effects of throat aspect ratio, geometric pitch and yaw vector angles on the infrared radiation characteristics of spherical convergent flap nozzles (SCFN)Results of the study indicate that: ① As the throat aspect ratio increases, the infrared radiation intensity in the vertical symmetry plane (zOx) decreasesWhen the throat aspect ratio is 3.5, the value along the 0° direction declines by 17.6% as compared with the round nozzleOn the other hand, increases of the infrared radiation intensity in the horizontal symmetry plane (yOz) are observed②The pitch vectoring causes the increase of infrared intensity along the direction 310°-350° in the zOxplane, and the yaw vectoring also causes the increase of infrared intensity along the direction 330°-350° in the yOzplaneThe infrared radiation intensities in the other symmetries are successfully suppressed.

Key words: spherical convergent flap nozzle, vector thrust, throat aspect ratio, infrared radiation, numerical simulation