Numerical study was done under the circumstances of the same total mass flow rate and the total temperature of inlet at 840 K to research the suppression effect of infrared radiation of plume of the engine in different kinds of crossflow injecting forms. The crossflow device was designed at the orifice of axisymmetric convergent nozzle. The injection of crossflow intensified the mixing of plume and outer air flow and thus decreased the length of hightemperature region. It is found that the mixing effect is distinctly worse than single or double oppositely injected when crossflow is circumferentially injected. At side detection plane

the suppression effect of infrared radiation of single and double opposite injecting comes very close when azimuthal angle is bigger than 20°

but the latter one is slightly better and has a maximum drop of 71.6%. At underneath detection plane

the infrared radiation intensity of single and double opposite injecting is stronger than that at side detection plane

and the latter has a close value when crossflow is circumferentially injected. At above detection plane

compared with other injecting forms

the infrared radiation intensity of single injecting is relatively weak and reaches a maximum drop of 78.4%.