Card Set Information
API 12 25
1. Describe the relationship between pressure and velocity in a closed system.
Together the make up total pressure.
2. How does subsonic airflow react through a convergent opening? Divergent opening?
: V increase and P decreases
: Vdecreases and P increases
3. How does supersonic airflow react through a convergent opening? Divergent opening?
: V increases P decreases
: V decreases P increases
4. What happens to the airflow as it passes through a nozzle? Diffuser?
: velocity increases and pressure decreases.
: velocity decreases and pressure increases.
5. What are the three sections of a gas turbine engine?
Compressor, burner, turbine
6. How does a gas turbine engine produce thrust?
By rapidly compressing, heating and accelerating a large quantity of air (mass) and fuel
7. What cycle explains the movement of air through a gas turnbine engine?
8. What happens to the velocity of the gases as they pass through the compressor section? The burner section? The turbines?
: Remains fairly constant.
Burner and turbine
9. What is gross thrust?
Thrust measured at exhaust at standard day conditions 29.92 and 15 degress Celsius
10. What is net thrust?
Thrust measured under normal flight conditions
11. When are gross thrust and net thrust equal?
When aircraft is in a static position and standard day conditions.
12. What affects the density of the air mass?
Temperature, pressure, and altitude.
13. What happens to thrust when air density decreases?
14. What happens to thrust when air temperature increases?
15. What happens to thrust when air pressure decreases?
16. What is the relationship between pressure and temperature as altitude increases?
Temperature and pressure both decrease with an overall decrease in thrust.
17. What is the optimum cruise altitude and why?
Approximately 36,000 ft. temperature remains isothermal.
18. How does airspeed and the ram effect change the amount of thrust produced at subsonic and supersonic airspeeds?
Airspeed increase without ram effect causes thrust to decrease.
Airspeed increase with ram effect causes thrust to remain relatively constant at subsonic speeds and increased greatly at supersonic speeds.