NIFE ENGINES QUESTIONS AND ANSWERS GRADED A+

NIFE ENGINES QUESTIONS AND ANSWERS GRADED A+ What is Bernoulli's theorem Any incompressible fluid that passes through a convergent opening, velocity increase, pressure decreases What is Bernoulli's Equation Pt=Ps+Pk Which type of air is compressible? Supersonic air What happens to Velocity and Pressure in a nozzle Pressure decreases, velocity increases What happens to Velocity and Pressure in a diffuser? Pressure increases, velocity decreases Draw the tootsie roll method Left side are diffusers, right side are nozzles What does an increase in pressure at the inlet do for the engine? It packs more oxygen tighter together so the engine runs more efficiently What is the shape of the inlet? Convergent-divergent What is the shape of an incompressible air diffuser? Divergent What are the events/components of the Otto and the Brayton Cycle? Intake, Compression, Combustion, Exhaust Explain what happens at each of the events in the Otto cycle Intake: Air is entering the valve while the piston is at the bottom Compression: The pressure is increased as the piston moves up Combustion: Spark ignites the air and sends the piston down Exhaust: the valve opens to release the air and start the cycle over What is the difference between the Otto and Brayton cycle? All events happen simultaneously in the Brayton cycle, while they happen in order in the Otto cycle What three parts does a gas turbine engine have at a minimum? What else can also be included? Compressor, Combustion Chamber/Burner, Turbine Inlet, Compressor, Diffuser, Combustion chamber/burner, Turbine, exhaust (I cant do complex turbine equations) What happens to temperature, pressure, and velocity at all 6 different parts of the gas turbine engine? What is gross thrust? Thrust solely from the velocity of the exhaust gases (ignores inlet) at standard day conditions (29.92 in/Hg and 15C) What is net thrust and its equation? Thrust that corrects for the inlet air. Net Thrust=m*(Vf-Vi)/t What is the thrust equation? T=m*a Explain what temperature, altitude, pressure, engine RPM, RAM Effect, and density do to thrust. (TAPERD) Explain the RAM effect in a gas turbine engine As the aircraft goes faster, more and more air is being rammed into the inlet. This increases the mass and pressure of the inlet air causing better engine performance. What are the cockpit thrust measuring devices? EPR (Engine Pressure Ratio) gauge, Torquemeter, and Tachometer What is a EPR? Engine pressure ratio. It measures the pressure ratio between the inlet and exhaust airflow What is a torquemeter and what type of aircraft use it? Indicated shaft horsepower available to drive the rotor or prop. Aircrafts that have rotors or props. What is a Tachometer? What is it measured in? Gauge used to measure engine performance/ speed. Measured in percent RPM What is the purpose of an inlet duct? What is it designed to act like (nozzle or diffuser)? Provides the proper amount of high pressure, turbulence free air that is steady and uniform to the first stage of the compressor. Diffuser. What shape is the inlet of a subsonic aircraft?