ENGINE COMPONENT DESIGN Cap. 7 AIAA AIRCRAFT ENGINE DESIGN R03-23/10/2013

Transcript

1 CORSO DI LAUREA MAGISTRALE IN Ingegneria Aerospaziale PROPULSION AND COMBUSTION ENGINE COMPONENT DESIGN Cap. 7 AIAA AIRCRAFT ENGINE DESIGN R03-23/10/2013 LA DISPENSA E DISPONIBILE SU Prof. Ing. Antonio Ficarella [email protected] 1

2 CONCEPT Università del Salento - FACOLTA DI INGEGNERIA INDUSTRIALE Brindisi chosen design point engine (referred as the reference point) behavior of the flow properties at the interfaces between the components this supplies the quantitative information necessary to allow separate design of each components 2

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5 TOTAL PRESSURE, ENTHALPY, TEMPERATURE 5

6 total pressure at the interface HP compressor - burner 6

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8 for a calorically perfect gas corrected mass flow rate corrected mass flow at the entrance of the fan 8

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10 at the entrance of the combustor 10

11 STATIC PRESSURE, ENTHALPY, TEMPERATURE, VELOCITY with the total pressure and temperature in hand, the static properties can be calculated from the isentropic compressible flow function (slide 5), provided that the local Mach number M and fuel/air ratio f are given the velocity can be calculated 11

12 ONE-DIMENSIONAL THROUGHFLOW AREA in the case of calorically perfect gas 12

13 FLOWPATH FORCE ON COMPONENT the net axial force in the positive x direction exerted on the fluid by each component force exerted on the fluid: I exit -I entry reaction force exerted by the fluid I entry -I exit a positive axial force on the fluid contributes a force on the component in the desired thrust direction 13

14 distribution of the major axial force throughout the engine axial force can be easily moved from the rotor to the stator by means of static pressure force applied to circular disks (balance piston) to manage the balance piston load so that most of the axial force is delivered to the stator assembly, which is attached to the outside case of the engine only enough net axial force on the shaft to ensure that it has the same sign under all operating conditions shaft thrust bearing 14

15 UNINSTALLED THRUST (effect of free exhaust jet) 15

16 TORQUE Università del Salento - FACOLTA DI INGEGNERIA INDUSTRIALE Brindisi the net steady-state torque on any rotating component must be zero, or the rotational speed would have to change freestream and exhaust flow usually have no swirl the net torque on the fluid is zero, and the net torque exerted by the stationary components must be zero 16

17 INTERFACE QUANTITIES 17

18 NET AXIAL FORCE 18

19 THETA BREAK AND THROTTLE RATIO turbomachinery limits the role of the control system maximum allowable compressor total pressure ratio and maximum allowable burner exit total temperature θ 0break =the control logic must switch from limiting c to limiting T t4 19

20 MAIN BURNER AND AFTERBURNER DESIGN 20

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22 INLET/EXAUST NOZZLE AREA 22

23 ENGINE COMPONENTS OPERATING LINE 23

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