1 MODULE 15, GAS TURBINE ENGINE 1- On an axial flow, dual compressor forward fan engine, the fan turns the same speed as the : a) High pressure compressor. „ b) Low pressure turbine. b) Forward turbine wheel . 2- A by-pass engine LP compressor : a) Supplies less air than is required for combustion. „ b) Supplies more air than is required for combustion. c) Supplies only the required quantity of combustion . 3- A turbo jet engine gives: a) Small acceleration to a large mass of air. „ b) Large acceleration to a small mass of air. c) Large acceleration to a large weight of air. 4- A jet engine derives its thrust by: a) Drawing air into the compressor. b) Impingement of the propelling gases on the outside air . „ c) Reaction of the propelling gases. 5- In a reverse flow system the last stage of an axial flow compressor is often centrifugal, this is to: „ a) Provide initial turning of the airflow . b) Prevent compressor surge. c) Increase the temperature rise. 6- In a free turbine: a) There is a clutch between compressor and power output shaft . „ b) There is no mechanical connection with the compressor . c) There is a direct drive with a free-wheel unit . 7- If an electrical de-icing system is operating, thrust will : „ a) Decrease. b) Increase. c) Remain constant. 8- A method of comparing engine efficiencies is by comparing: a) Thrust to weight ratio. b) Fuel consumption . „ c) Specific fuel consumption. 9- "Ram effect" due to aircraft forward speed will cause the efficiency of the engine to: a) Remain constant. „ b) Increase. c) Decrease 10-The efficiency of a gas turbine engine at altitude: a) Decreases. „ b) Increases . c) remains constant . 11- Bernoulli's Theorem states that at any point in a flow of gas: a) The static pressure is less than the dynamic pressure. b) The static pressure and dynamic pressure are equal . „ c) The total energy remains constant .
2 12- A bypass ratio of 5:1 indicates that the bypass flow is: a) Equal to 1/5 of the hot stream . b) Five times the cold stream. „ c) Five times the hot stream. 13- In a turbo jet engine, combustion occurs at: a) Constant velocity. b) Constant volume. „ c) Constant pressure. 14-The working fluid of a gas turbine engine is : „ a) air b) Gasoline c) Kerosene 15- As subsonic air flows through a convergent nozzle the velocity: „ a) increases . b) decreases. c) remains constant 16- The stator vanes in an axial-flow compressor : „ a) convert velocity energy into pressure energy. b) Convert pressure energy onto velocity energy . c) Direct air into the first stage rotor vanes at the proper angle. 17-What units in a gas turbine engine aid in stabilization of the compressor during low thrust engine operations? „ a) Bleed air valves . b) Stator vanes. c) Inlet guide vanes. 18- A nozzle is „choked‟ when the gas flow or air flow at the throat is : a) Subsonic.
- Summer '17
- sajad heidari
- compressor, RPM, gas turbine engine, Axial compressor