Effect of Tabs Fixed on a Convergent-Divergent Nozzle on Infrared Radiation of Exhausting Jet

The effect of tabs fixed on a convergent-divergent nozzle on the infrared radiation of the exhausting high speed (subsonic and supersonic) hot (about 640℃) jet was investigated,and the influence of tab block ratio and inclined angle on the suppression of infrared radiation was studied.The results show that tabs can cut down a good lot of hot jet core length and suppress the infrared radiation up to 57% from the hot jet.The increase in tab block ratio of 1% decreases the infrared radiation intensity of the whole hot exhausting gas by about 5 5% in average,and the increase in tab inclined angle by 1 degree can suppress the infrared radiation intensity of the whole hot exhausting gas by about 0 21% in average in the test conditions.