What are the advantages of a reverse flow combustor?
Posted by Glum_Ad1550@reddit | aviation | View on Reddit | 7 comments
As per question. I heard it is a recent design and becoming increasingly common.
OrionAstronaut@reddit
Reverse flow combustor is typically chosen when you care about having a short shaft on your engine, since the combustor can hang around your turbine (think of the whittle engine). Short shaft gives you a stubbier aspect ratio for your rotor and improves rotordynamics, which was critical for early jet engines. This also lets you add extra combustor volume without sacrificing installation area. Increasing volume reduces its loading, or how much heat must be released from the fuel in a given volume, enhancing combustion efficiency (energy released vs. energy stored in fuel). The reverse flow itself lends itself to some of the incoming air to be pre-heated by the exhaust, albeit at the cost of extra pressure drop. Its a good choice for when you have a centrifugal stage that needs the extra radius anyways for the diffuser system, which the overhung combustor can sit behind.
OkAddendum7844@reddit
It reduces the overall length of the engine
It improves combustion efficiency. In theory, ideal combustion occurs as a zero velocity, constant pressure process. Obviously this is not physically attainable, but it helps reduce pressure and velocity gradients across the combustor.
andrewrbat@reddit
An advantage is that it allows for an intake that can separate out fod (often with an inertial separator) and not add ridiculous length to the cowl.
-burnr-@reddit
Don’t know about recent. Reverse flow turbines have been around since the late 1950s/early 1960s
savage-cobra@reddit
There’s less time between the Wright Flyer and the when the PT6 first flew than between its first flight and now. I really don’t know where he’s getting that it’s a new design.
XYooper906@reddit
PT6 enters the chat.
p50one@reddit
Compact design