On a modern high-bypass turbofan engine, typically what percentage of the thrust comes from ...?

Question

... the cold fan, compared to the hot jet thrust leaving the low pressure turbine?

I am just asking out of general interest (I've just been to an airshow) so am just wanting a rough idea. By 'typical' I am thinking of a newly built commercial jet airliner engine at typical cruising airspeed, throttle and altitude.

Answer 1

Typically, 85 percent from bypassed or cold stream and 15 percent from hot exhaust nozzle

Answer 2

Typically, nowadays, 70-75% is going though the low pressure turbine, and 25-30 % through the high pressure turbine, compressed, and ignited.

With the next gen engines though, that figure will most likely become what the previous answerer said. 80%-85 % bypassed.

----------------some figures---------------------------------...

General Electric CF6-80XXXX-------->used on quite a few airliners, boeing and airbus. , 747,767, A330, A310, A300, AWACS E4, DC10, MD11.

bypass ratio is 5/2. meaning for 7 pounds of air, 5 goes into the low pressure turbine and bypassed and 2 pounds go through the high pressure turbine, compressed and then ignited.

GE90 XXXX------->6/2 bypass ratio (used on 777s)

GE GENX -----will be used on 787 bypass ratio of 9.5  (9.5 lbs bypassed for 1 lbs compressed and combusted)

Rolls Royce Trent 1000------will be used on 787, bypass ratio of 11.

Pratt & Whitney 4000 (successor to the JT9D) used on variants of the Airbus A300, A310, 747, 767 and MD11.

Bypass ratio of 5.1