may vary in operation of turbine engine 10 incoming airflow f i enters inlet 22 and divides into core flow f c and bypass flow f b downstream of fan 12 core flow f c propagates along the core flowpath through compressor section 16 combustor 18 and turbine section 20 and bypass flow f b propagates along the bypass flowpath through bypass duct 14 lpc section 30 and hpc section 32 of compressor 16 are utilized to compress incoming air for combustor 18 where fuel is introduced mixed with air and ignited to produce hot combustion gas depending on embodiment fan 12 also provides some degree of compression or pre compression to core flow fc and lpc section 30 or a portion of it may be omitted alternatively an additional intermediate spool is included for example in a three spool turboprop or turbofan configuration combustion gas exits combustor 18 and enters hpt section 38 of turbine 20 encountering turbine vanes 34 and turbine blades 36 turbine vanes 34 turn and accelerate the flow and turbine blades 36 generate lift for conversion to rotational energy via hpt shaft 42 driving hpc section 32 of compressor 16 via hpt shaft 42 partially expanded combustion gas transitions from hpt section 38 to lpt section 40 driving lpc section 30 and fan 12 via lpt shaft 44 exhaust flow exits lpt section 40 and turbine engine 10 via exhaust nozzle 24 the thermodynamic efficiency of turbine engine 10 is tied to the overall pressure ratio as defined between the delivery pressure at inlet 22 and the compressed air pressure entering combustor 18 from compressor section 16 in.