A turbofan engine operates at intermediate thrust (afterburner off) with the following characteristics:
Ambient temperature = 298.15K
Ambient pressure = 101300N/m2.
Bypass ratio b = 0.6
Compressor pressure ratio pc = 25
Fan pressure ratio pf = 3.375
Fuel heating value qr = 19000Btu/lbm
Turbine inlet temperature = 2000K
Diffuser pressure recovery factor rd = 0.9
Compressor efficiency hc = 0.89
Fan efficiency hf = 0.91
Combustion efficiency hb = 0.98
Burner pressure recovery factor rb= 0.95
Turbine efficiency ht = 0.98
Nozzle efficiency hn = 1.0
Calculate the thrust per unit mass flow rate, and the thrust specific fuel consumption. Later, for a specified value of thrust, determine the area at the choked turbine exit, which limits the mass flow rate.
Such a problem can be solved by going station by station through the engine and using simple thermodynamic relations. Since the component efficiencies are specified, we don't have to go into detailed multi-dimensional flow and chemical analyses for each component.
Station 1: inlet
p01 = p0a: isentropic external acceleration or deceleration
T01 = T0a: no work done, except that of expansion or contraction.>
Station 2: end of diffuser, beginning of compressor & fan:
T02 = T01: adiabatic, no work
p02= rdp01: includes the given stagnation pressure loss