15.1 Fundamentals Flashcards
(25 cards)
What is energy
The ability to do work
What are the two types of energy and their equations
Kinetic - 1/2 x m x v^2
Potential - mgh
Newtons 1st,2nd and 3rd law
1st - inertia
2nd - F = ma
3rd - Action and reaction
What is total pressure
The combination of dynamic and static pressure in a flow
In a convergent and divergent duct what is dynamic and static
Dynamic = velocity
Static = pressure
What is the brayton cycle
Constant pressure and continuous combustion
What does isobaric mean and what stage is it applied in a turbine engine
Constant pressure in the combustion stage
what stage is isentropic applied in a turbine engine
Compression
What is the equation and SI units for force
Mass x acceleration, lbs/N
What is the equation and SI units for work
Force x distance, J/Nm
What is the equation and SI units for power
Force x distance/time, W/ Nm/s
What is the equation and SI units for acceleration
Change in velocity/time, m/s^2
What do engines supply to a/c (aircraft)
Hydraulic power, electrical power, bleed air, pneumatics
How does a turbofan engine work
Turbo-fan engines are manufactured with either a twin spool or three spool arrangement, a spool consist of a turbine driving a compressor through a shaft.
Advantages and disadvantages of turbojet engine
Advantages of turbojet engine:
Relatively simple design
Capable of very high speeds
Takes up a smaller frontal area
Disadvantages of turbojet engine:
High fuel consumption
Loud
Poor performance at slow speeds
Limited in range and endurance
Advantages and disadvantages of turbo fan engines
Advantages of turbofan engine:
Fuel efficient
Quieter than turbojets
Streamlined appearance
Disadvantages of turbofan engine:
Heavier than turbojets
Larger frontal area than turbojets
Inefficient at very high altitudes
What drives the propeller in a turboprop
Shaft horsepower
What is the difference between turboprop and turbojet engines
additional turbines, a power shaft, and a reduction gearbox have been incorporated into the design to drive the propeller.
Advantages and disadvantages to turboprop engines
Advantages of turboprop engine:
Very fuel efficient
Most efficient at mid-range speed between 250 - 400 knots
Most efficient at mid-range altitudes of 18 000 - 30 000 feet
Disadvantages of turboprop engine:
Limited forward airspeed
Gearing systems are heavy and can break down
What does the turbo shaft engine do
Produces shaft power to drive machinery
Advantages and disadvantages to turbo shaft engines
Advantages of turboshaft engine:
Much higher power-to-weight ratio than piston engines
Typically, smaller than piston engines
Disadvantages of turboshaft engine:
Loud
Gear systems connected to the shaft can be complex and break down
What does a spool represent
Number of turbines, shafts and compressors
What letter is used to represent the spool speed
N
