Question

Plume emissions can be reduced by ___________

(a) quickly mixing exhaust with outside air

(b) increasing exhaust temperature

(c) increasing engine outlet temperature

(d) increasing plume temperature

I have been asked this question at a job interview.

My doubt stems from Configuration Layout Considerations in division Configuration Layout Considerations of Aircraft Design

Answer 1

Correct choice is (a) quickly mixing exhaust with outside air

To elaborate: Plume emissions can be reduced by quickly mixing the exhaust of engine with outside air. Emissions from hot parts are reduced by cooling them. Increase in temperature will increase emissions and as a result, it will increase IR detection as well.