2A651 Aerospace Propulsion Vol 2 Self-Test

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2A651 Aerospace Propulsion Vol 2 Self-Test
2012-01-03 01:16:54

2A651 Aerospace Propulsion Vol 2 Self-Test
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  1. What does Newton’s first law of motion state?
    "a body at rest stays at rest and a body in motion continues to move at a constant speed in a straight line unless an external force acts upon it"
  2. Newton’s first law of motion is also considered the definition of what term?
  3. What is Newton’s second law of motion?
    An unbalanced force on an object is directly proportional to the mass of the body of the object
  4. Which law of Newton’s laws best explains why a jet engine produces forward thrust?
    newtons third law
  5. What two words can best sum up Newton’s third law of motion?
    Action and Reaction
  6. What does Bernoulli’s principle state?
    Speed and pressure are inversley proportional, speed up-pressure down, speed down-pressure up
  7. What type of duct is used to decrease pressure and increase velocity?
    convergent duct
  8. How does the design of an airfoil influence pressure above and below the airfoil to produce lift?
    it increases the velocity and decreases pressure
  9. What type of energy does a falling object possess?
  10. Can energy pass from potential to kinetic and back to potential?
  11. Which jet engine section produces the large volumes of air required for the production of thrust?
  12. What does the combustion section do to support the production of thrust?
    introduces fuel and burns it in the air stream behind the compressor
  13. Which engine section drives the compressor?
  14. What is the energy that is expended through the exhaust nozzle used for?
    It creates the thrust that sends the acft forward
  15. What is used to create the propulsive force for a turboprop engine?
  16. Which terms are used to express the thrust produced by a T56 engine?
    horsepower and pounds of torque
  17. Which term is used to define the theoretical power of a frictionless engine?
    indicated horsepower
  18. What is friction horsepower?
    indicated horsepower-brake horsepower
  19. Which type of horsepower determines the performance of the engine-propeller combination?
    thrust horsepower
  20. What can you determine if you know the Btu content of a gallon of fuel and how much the gallon
    of fuel weighs?
    the potential horsepower of the fuel
  21. What type of fuel do today’s jet engines use?
  22. The thermal efficiency of a jet engine is equal to what?
    the energy produced by the engine divided by the energy of the fuel consumed
  23. What two factors determine what proportion of the energy of a fuel is actually used to propel an
    aircraft forward?
    thermal and propulsive efficiency
  24. Define the term “barometric pressure.”
    the force exerted by the mass of a column of air above the point where the pressure is being measured
  25. What instrument is used to measure barometric pressure?
  26. Why is a measurement of 14.7 psi sometimes referred to as a “standard-day” atmospheric
    because one square inch of mercury would wiegh 14.7 pounds
  27. Why was a US standard-day condition developed?
    because a standard was required for a point of reference
  28. What two factors tend to cause variations in the temperature of the atmosphere?
    altitude and latitude
  29. Define the term density, as it applies to air.
    material mass unit per volume
  30. List the three methods by which heat can be transferred.
    radiation, convection, and conduction
  31. Where is the point of highest pressure within a jet engine?
    in the diffuser
  32. On a jet engine that does not have an afterburner, where is the point of highest temperature?
    the combustion section
  33. When a jet engine reaches idle speed, what determines how the fuel control regulates engine
    power lever setting
  34. What two forms of energy does a jet engine produce?
    thrust and heat
  35. Approximately what percent of the energy produced by the fuel is needed to maintain the jet
    engine operating cycle?
  36. Why does the airflow velocity of the exhaust gases increase within the turbine stator?
    because the size of the openings the gas flows through is required
  37. Where is the point of highest airflow velocity in a jet engine?
    ejector nozzle
  38. What component directs the gases that strike the turbine wheel blades?
    turbine stator
  39. What is the purpose of the turbine stator?
    it increases the velocity of the gasses hitting the turbine blades
  40. After the gases leave the turbine section and enter the exhaust section, what type of velocity do
    they have?
  41. What straightens the flowpath of gases in the exhaust case?
    the vanes in the exhaust case
  42. In a multistage turbine, what is the arrangement of the shafts?
    one shaft is hollow allowing the other shaft to operate inside it
  43. Which turbine drives the front compressor on a dual-spool engine?
    the rear turbine
  44. What is a turbojet engine?
    an air dependant thermal jet engine
  45. Name the three main sections of a gas turbine engine.
    compressor burner and turbine
  46. Today’s jet engine compressors are an outgrowth of what units that are normally used with
    reciprocating engines?
    the turbosuprechaarger
  47. What requirement must exist for the successful operation of either jet or reciprocating engines?
    the engines must be able to handle large amounts of air in a short period of time
  48. How do pressure pulsations in a centrifugal compressor appear?
    as shockwaves or irregular movement of air through the compressor
  49. What effect do pressure pulsations have on a compressor?
    rapidly reduced efficiency
  50. For what two reasons is it undesirable to use multiple-stage centrifugal compressors to increase
    the pressure ratio?
    complicated construction and increased wieght
  51. What is the purpose of the inducer rotor?
    toguide air into the succeeding rotor wheel
  52. How many shafts comprise the compressor/turbine shaft assembly?
  53. Why is the forward end of the compressor-turbine shaft hollow?
    to provide fuel to the entire engine
  54. What two needs stimulated the development of the axial-flow compressors?
    more powerful and economical
  55. How are axial-flow compressor rotor blades similar to an aircraft propeller?
    they are both air foil shaped
  56. How is the air processed through an axial-flow compressor?
    the air pressure is increased at each stage of compression
  57. What is the purpose of the stationary vanes that are located behind each rotor wheel in the singlespool
    axial-flow compressor?
    they direct air onto the blades and increase pressure
  58. How are the compressor rotor blades and stator vanes arranged in a multiple-stage axial-flow
    the stator vanes correspond to the length of the rotor blades
  59. Identify two reasons the dual-spool compressor was designed.
    ease of starting and reduction of stalls
  60. What unit determines the speed of the N2 (high-pressure) rotor in a dual-spool compressor?
    fuel conntrol
  61. Which type of compressor is more durable, the axial-flow or the centrifugal?
  62. How are the stator vane rings attached to the axial-flow compressor casings?
    dovetailed to the inside
  63. From what three types of alloys are compressor cases made?
    titanium, steel, and aluminum
  64. What is the purpose of the air chamber in axial-flow compressor engines?
    to bleed air from the compressor
  65. What achieves diffusion in axial-flow compressor engines?
    the divergent shape of the compressor guide vane
  66. Why is getting good combustion in a gas turbine engine so complex?
    because the air-fuel ratio must be perfect
  67. What is “combustion efficiency?”
    a way to rate the combustion chamber
  68. How is combustion efficiency computed?
    by comparing the heat energy with the known energy in the combustion chamber
  69. Within certain limits, what happens to combustion efficiency as combustion-chamber inlet pressure increases?
    it increased
  70. What is the most probable cause if a jet engine flying at 40,000 feet with a constant engine rpm of 50 percent has a flameout?
    the rpm is too low
  71. List three conditions that are of relatively small concern if the upper limit on combustionchamber temperature rise is outside steady-state operating range.
    inlet pressure, temp and airflow
  72. What are two by-products of combustion?
    carbon deposits and carbon monoxide
  73. How does engine design help to prevent igniter plug fouling?
    by directing air around the igniter plug electrodes
  74. Describe carbon monoxide gas.
    its colorless, odorless, and poisonous
  75. What are the two purposes of the combustion section?
    to burn the fuel and deliver the resulting gas to the turbine
  76. What is the approximate air-to-fuel ratio that is used for the actual burning process in a combustion chamber?
  77. Name the three types of combustion chambers.
    can, annular, and can annular
  78. What supports the annular-type combustion chamber in the front and rear?
    the burner support
  79. How does the additional air that is required to support combustion and cool the annular combustion chamber reach the chamber walls?
    through slots and holes in sections of the chamber walls