An experiment was conducted to study the influences of airflow parameters on exit temperatures of an infrared suppressor model.The temperature of the main flow was about 610 ℃ and the pressure of the main flow was atmospheric pressure.The downwash flow velocity ranged from 4.4 to 11 m/s.The temperature of downwash flow was atmospheric temperature.The results show that

the exhaust flow temperature grows linearly with the increase of the main nozzle flux.The entrainment coefficient decreases with the increase of the downwash flow.With the increase of the downwash flow velocity

the exhaust temperature has a peak value the exhausting duct temperature decreases with the increase of the downwash flow velocity.The averaged gas velocity of flowing backward between the exhausting duct and the mixture tube increases with the rise of the main nozzle flux and the downwash flow velocity.