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- georgem2012
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Bypass Flow and Core Flow velocities
I realise the bypass Flow provides the larger proportion of the overall thrust, however, in say a high bypass ratio turbofan engine such as a GE90 or a Trent 900, what is the difference in speeds of the bypass and core airflows at maximum thrust?
Re: Bypass Flow and Core Flow velocities
Typically core flow exit velocity is in the vicinity of Mach 1 and bypass duct velocity is around Mach 0.3... Since the mass flow rate through the bypass duct is higher, it contributes a higher chuck of total thrust.
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- GalaxyFlyer
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Re: Bypass Flow and Core Flow velocities
Are those numbers absolute or velocities above vehicle speed?
GF
GF
Re: Bypass Flow and Core Flow velocities
Can't be absolute. In order to produce thrust, bypass flow must be accelerated above the vehicle speed. I would guess the delta starts big at take off and then gradually shrinks as the plane picks up speed. But never reaches zero.
Core flow could produce thrust at absolute speeds equal or even a bit lower than vehicle speed due to the added mass of the fuel. But in practice, they are higher anyway, given the "low" speed of commercial aircraft.
Core flow could produce thrust at absolute speeds equal or even a bit lower than vehicle speed due to the added mass of the fuel. But in practice, they are higher anyway, given the "low" speed of commercial aircraft.
Re: Bypass Flow and Core Flow velocities
Those are velocities measured at the exit of the core and bypass nozzles respectively. Those numbers usually apply to cruise conditions.
Its hard to give you real numbers in mph or m/s since these value depend on flow temperature at exit as well as the geometry of the nozzle & altitude.
Its hard to give you real numbers in mph or m/s since these value depend on flow temperature at exit as well as the geometry of the nozzle & altitude.
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