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Water to make engine emissions reduce?? Question 990463

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  • Water to make engine emissions reduce?? Question 990463

    Are you sure that injecting water into the engine makes it run better and more efficient? Increase mass flow and reduce emissions?? Why are we not doing this in all planes then?

    or should the question be: correct, instead of incorrect?

  • #2
    It really does! Injecting water into the turbines cools them down, enabling more fuel to be burned - more bang for your buck. But of course you have the weight penalty of the water to bring into the equation. Harrier jets, for example, carried about 500 lb of demineralised water to inject into the engine for a hover landing. Gave them as much as 30 seconds of hover on a hot day! But no longer used in aviation, nor listed in the EASA learning Objectives (LO's). I have placed the question as inactive, so it should not appear again from tomorrow morning.

    For the record, the 'correct' incorrect answer is indeed the one about reheat fuel. It is injected into the exhaust stream, not the turbine. But nothing uses it now since the sad demise of Concorde. We also do not like questions that ask for the 'incorrect' answer to be selected - it is negative learning. They are mostly weeded out from the EASA QB nowadays, thankfully...

    Hope that helps!


    • #3
      It really does! Many many thanks for this elaborate answer! Very interesting to read! 😃