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8/13/2019 My Scramjet
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ByHimanshu Gupta
111638
I have one speed,I have one Gear;
Go!
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A scramjet (supersoniccombustion ramjet) is avariant of a ramjet air
breathing combustionjet engine in whichcontinuous combustionprocess takes place insupersonic airflow.
Requires forwardmotion to producethrust
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Scramjets operate at
hypersonic (>Mach 5)velocities, through flow
and combustion takesplace at supersonic
velocities.
No operational systems,but a number of testflights and many ground
tests
Ramjets fly at high
subsonic to supersonicspeeds but the airflow
through them and theircombustion is subsonic
velocities.
Widely used for missiles,and on a few aircraft.
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A CONVERGING INLET,
where incoming air iscompressed and
decelerated. A COMBUSTOR, where
gaseous fuel is burned with
atmospheric oxygen to
produce heat. A DIVERGING NOZZLE,
where the heated air is
accelerated to produce
thrust.
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Scramjet works on the same principle of Ramjet.
All the operations are done by the varying cross section ofpassages.
There are inlet passage, diffuser passage, combustion passage andexhaust passage.
Basically in order to achieve the initial speed, a second engine is
integrated in the Scramjet model, it may be rocket or turbojetengine.
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As these are air breathing engines, air from the
atmosphere enters at very high speed in the inletpassage.
Hence the air from the atmosphere enters in the inlet
section having very high velocity is reduced in
diffuser section; thereby its static pressure increases.
Temperature of air also increases when passingthrough the narrow cross section towards
combustion chamber.
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Hot air flows in the combustion chamber and at thismoment the propellant i.e. hydrogen (having a very
low ignition temperature) as a fuel are injected by the
injector in the combustor.
Where it gets self ignited within a millisecond andthe combustion process is carried out at the
supersonic speed.
The fresh air supply to the diffuser builds up a
pressure at the diffuser so that these burned gases
cannot expand towards the diffuser.
Instead, the gases are made expand in combustor
towards tail engine hence providing the required
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Artist's conception of the NASA X-43with scramjetattached to the underside
http://en.wikipedia.org/wiki/NASA_X-43http://en.wikipedia.org/wiki/NASA_X-43http://en.wikipedia.org/wiki/NASA_X-43http://en.wikipedia.org/wiki/NASA_X-438/13/2019 My Scramjet
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Ramjets and Scramjets have been used in
missiles, helicopters, and the SR71 Blackbird withvarying degrees of success.
http://upload.wikimedia.org/wikipedia/en/c/c8/Hiller_YH-32_Hornet.jpg8/13/2019 My Scramjet
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Does not have to carryoxygen
No rotating parts makes
it easier to manufacture
Higher speed could meancheaper access to outerspace in the future
Higher efficiencies
Testing difficulties:-expensive launch
vehicles, both of which
lead to high
instrumentation costs. A scramjet cannot
produce efficient thrust
unless boosted to high
speed, around Mach 5,although depending on
the design it could act as a
ramjet at low speeds.
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