《航空器系统工程学》（英文版）Propulsion Systems

Propulsion Systems

Propulsion Systems

Major US Airline Year 2000 Operating Costs st per ASM=9.75 g Aircraft Fuel 13% Engine Maint Material OSR 2% Engine owners Salaries 3% 40% Airframe Ownership 10% Airframe Maint. Material &OSR anding fees and other rents Passenger service Other 13% Selling expenses asset write-downs, other non-recurring items

Major US Airline Year 2000 Operating Costs Cost per ASM = 9.75 ¢ Aircraft Fuel Engine Maint. Material & OSR 2% Engine Ownership Salaries 3% 40% Airframe Ownership 10% Airframe Maint. Material &OSR 2% Landing fees and other rents 5% Passenger service Other 3% 13% 13% Selling expenses 9% "Other" includes contracted services, asset write-downs, other non-recurring items

Airplane Operating Cost Comparison 25% 20% aooo508 Current state-ofArt d 5% 15%GOAL 20% 25%30% 40% Relative Cash DoC per Trip

-20% -15% -10% -5% 0% 5% 10% 15% 20% 25% 30% -15% -10% -5% 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% Relative Cash DOC per Trip Relative Cash DOC per Seat Airplane Operating Cost Comparison Three Class Seating 3000 nm Trip Seats = Constant GOAL -10% Current State-of-Art Increasing Seats

Typical Engine-Related Airline Cost Breakdown Initial Cost ( List) 33% Fuel cost 54% Maintenance Cost 13% 777-200ERPW4090 sO.75/gal Fuel Price

Typical Engine-Related Airline Cost Breakdown 33% 13% 54% Initial Cost (List) Maintenance Cost Fuel Cost 777-200ER/PW4090 $0.75/gal Fuel Price

Thrust sizing requirements LImit Number of Engines Aircraft Max Take Off Gross Weight W/S X Limit Take Off Field Length · Time to climb Cruise altitude and mach number Lift to Drag of Wing Aircraft Potential Growth

Thrust Sizing Requirements Y Limit TOGW T/W W/S X Limit • Number of Engines • Aircraft Max Take Off Gross Weight • Take Off Field Length • Time to Climb • Cruise Altitude and Mach Number • Lift to Drag of Wing • Aircraft Potential Growth

Basic engine relationships Thrust =(Velocity of exhaust-velocity of aircraft Mass Overall engine efficiency=n thermal X n propulsive

Basic engine relationships Thrust = (Velocity of exhaust - velocity of aircraft) Mass Overall engine efficiency = K thermal X K propulsive

Overall Engine Efficiency Includes Two Processes Energy Conversion and Thrust Production Gas generator Available Propulsion - Energy Fuel Input n overall = n thermal X n propulsive

Overall Engine Efficiency Includes Two Processes: Energy Conversion and Thrust Production Gas Generator Available Propulsion Energy Fuel Input K overall = Kthermal X Kpropulsive

Thermal efficiency measures the process of converting chemical energy of the fuel into energy available for propulsion Function of overall pressure ratio and component efficiencies Current engines at 40: 1 overall pressure ratIo Future engines at 60: 1 overall pressure ratio

Thermal efficiency measures the process of converting chemical energy of the fuel into energy available for propulsion - Function of overall pressure ratio and component efficiencies - h s Current engines at 40:1 overall pressure ratio Future engines at 60:1 overall pressure ratio

Propulsive efficiency measures the process of converting energy available for propulsion into useful propulsive power Gas generator Gas generator Turbofan or Turboprop Gas generator propulsive→100% as exhaust→vo

Propulsive efficiency measures the process of converting energy available for propulsion into useful propulsive power Gas Generator Gas Generator Turbofan or Turboprop Gas Generator Kpropulsive 100% as Vexhaust Vo

Lower specific thrust is fundamental to improving fuel economy Engine efficiency goodness Fuel economy Drag/thrust/ Weight/thrust Specific thrust(Ib /Ib mass) Increasing bypass ratio

Lower specific thrust is fundamental to improving fuel economy goodness Fuel economy Drag/thrust Engine efficiency Weight/thrust Specific thrust (lb /lb mass) Increasing bypass ratio