Abstract:

Aiming at the infrared suppressor for a type of turboshaft engine which exhausts in front, a new idea of suppressor structure combining lobed nozzle with film cooling mixing duct is brought forward, with the purpose of decreasing infrared radiation of the mixing duct wall. Through model experiment, the internal aerodynamic and infrared radiation characteristics of the filming cooling mixing duct are revealed. The experimental results show that the static pressure at the three pumping inlets is under the ambient pressure. And the drive force of pumping environment atmosphere is become naturally.The pumping ratio of mixing duct has a certain relation with the temperature ratios of the primary and secondary flows.The results on the hot condition can be deducted from that on the cold condition through the corrected index of temperature. Film cooling mixing duct enhances the pumping performance of the whole suppressor system by 30% comparing with the case without film cooling mixing duct,but induces the total pressure loss only by 1%.Infrared radiation intensity of the film cooling mixing duct is reduced by 12%-27% within 3-5 μm band and by 12%-28% within 8-14 μm band.

Key words: film , cooling , mixing , duct,  , infrared , suppressor,  , lobed , nozzle,  , infrared , radiation,  , pumping