Experiments on infrared radiation characteristics of exhaust system for a turbofan engine

One fifth scaled model was constructed for the turbo-fan exhaust system according to one-type engine for experimental research.The capability of infrared radiation suppression of the lobed forced-mixer was validated by some model experiments.The experimental data show the lobed forced-mixer can decrease the exhaust system infrared radiation.In detail,the lobed forced-mixer enhances the mixing between core flow and bypass flow to decrease the plume temperature by 11% and infrared radiation intensity by 7.3%～22.6% within 3～5 μm band as compared to confluent mixer.The bypass ratio was enhanced from 0.233 to 0.685,plume temperature reduced by 21% and infrared radiation intensity depressed by 30%～59% at different detected angles within 3～5 μm band.The plume and interior wall temperatures decrease accounts for the depression of exhaust system radiation intensity.