For those who would like to understand it in simpler form:
In a
turbofan (bypass) engine, the bypass ratio is a comparison between the mass flow rate of air drawn into the engine through the fan disk that goes
around the engine core with the mass flow rate of the air that goes
through the engine core. In an engine with a bypass ration of 10:1, for every 11 units of air drawn into the engine, 10 will bypass the engine core and 1 will go through it.
In short for every 10 parts of air thrown out by the main fan 1 part of air goes through the engine burning the fuel and thrown out of the nozzle.
This is the normal type of operation one would see in a passenger planes’ turbofan engine.
But in an engine like F110 which has a by pass ratio of 0.76:1;
for every 0.76 part of air thrown out by the main fan, 1 part of air is used in the burning of fuel andthrown out of the nozzle.
So if the by pass ratio of TF6000 is 1.08 , then for every 1.08 part of air thrown out by the main fan, 1 unit of air goes through the engine’s hot parts.
This makes the TF6000 engine a little higher by pass than an engine like f110. But not a high by pass engine like the ones we would see in jet liners where around 90% of thrust is provided by the air thrown out around the engine by the big fan.
Both RR Turbomeca and Honeywell F125 have lower by pass ratios than TF6000. Higher bypass engines are quieter and more suitable to stealth operations. Technology used on engines like RR Pearl with higher by pass ratios are being used for the basis on which the tempest engine is being produced.