The engine type represented in the drawing is a 951 ? Diploma > registration
When the combustion gases pass through a turbine the ?
When combustion gases pass through a turbine
Regarding a jet engine I The maximum thrust decreases as the pressure altitude increases II The specific fuel consumption is inversely proportional to pressure altitude at constant TAS ?
Regarding a jet engine i the maximum thrust decreases as pressure altitude increases ii the specific fuel consumption inversely proportional to pressure altitude at constant tas I correct ii correct.
jet engines are more efficient at higher altitudes because less fuel needed a given thrust due to reduction in lift drag lower temperatures through inlet cause a significant reduction in specific fuel consumption up to tropopause
specific fuel consumption the amount of fuel burnt per unit of thrust for jets it reduces with altitude up to tropopause. Regarding a jet engine i the maximum thrust increases as pressure altitude decreases ii the specific fuel consumption proportional to pressure altitude at constant tas I correct ii incorrect.
jet engines are more efficient at higher altitudes because less fuel needed a given thrust due to reduction in lift drag lower temperatures through inlet cause a significant reduction in specific fuel consumption up to tropopause
specific fuel consumption the amount of fuel burnt per unit of thrust for jets it reduces with altitude up to tropopause. One of advantages of an annular combustion chamber A reduced thermal stress on turbine. A combustion chamber a very complex structure with its divergent convergent passages compare to old multi can combustion system annular combustion chamber are shorter lighter cheaper with improved combustion characteristics more power greater efficiency the main driver in combustion chamber development the need to equalise temperature flow around whole turbine entry ring in order to reduced thermal stress. The correct order of decreasing freezing points of three mentioned fuels Jet a jet a jet b. The accepted minimum fuel temperature safe flight for
jet a 40°c
jet a 1 47°c
jet b 65°c. Labyrinth seals in lubrication system of a gas turbine engine are designed to provide a seal that Not completely tight allowing some movement between rotating static parts. The accepted minimum fuel temperature safe flight for
jet a 40°c
jet a 1 47°c
jet b 65°c. 8 Regarding a jet engine i the maximum thrust decreases as pressure altitude increases ii the specific fuel consumption decreases slightly as pressure altitude increases at constant tas I correct ii correct. Jet engines are more efficient at higher altitudes because less fuel needed a given thrust due to reduction in lift drag lower temperatures through inlet cause a significant reduction in specific fuel consumption up to tropopause
specific fuel consumption the amount of fuel burnt per unit of thrust for jets it reduces with altitude up to tropopause. 9 The characteristics of an axial compressor are 1 a low pressure ratio stage2 a high pressure ratio stage3 possibility of compressing a large mass airflow4 inability of compressing a large mass airflowthe combination that regroups all of correct statements I correct ii correct.
the key word here by stage! a centrifugal compressor will produce about 5 1 ratio per stage (ie impeller & diffuser) compared to a axial that gives about 1 2 1 per stage however use of multi stage axial compressors gives a bigger overall ratio. 10 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the speed decreases in flow direction ii the total pressure remains constant in flow direction I correct ii correct. There a velocity decrease as air flows from a small inlet to a larger outlet. 11 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the static pressure increases in flow direction ii the total temperature remains constant in flow direction I correct ii correct. In a divergent duct with subsonic flow static pressure rises as does static temperature but total temperature remains constant. 12 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the dynamic pressure decreases in flow direction ii the static temperature increases in flow direction I correct ii correct. In a divergent duct with subsonic flow static pressure rises as does static temperature but total temperature remains constant. 13 A flat rated turbofan engine has a constant maximum rated thrust level Up to a specific oat.
the term flat rating so called because of flat nature of thrust versus ambient temperature curve the curve shows that from lowest operating temperature possible to specified temperature engine produces full thrust above this temperature full thrust will not be permitted
a 'flat rate turbofan engine controlled in such a way that at constant ambient air pressure there no variation of take off thrust with air temperature up to some specified temperature limit
above that limit engine operates in such a way that either
fan speed or compressor speed constant or
turbine inlet temperature constant
and in either case thrust then decreases with increasing temperature. 14 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the dynamic pressure decreases in flow direction ii the static temperature decreases in flow direction I correct ii incorrect.
the term flat rating so called because of flat nature of thrust versus ambient temperature curve the curve shows that from lowest operating temperature possible to specified temperature engine produces full thrust above this temperature full thrust will not be permitted
a 'flat rate turbofan engine controlled in such a way that at constant ambient air pressure there no variation of take off thrust with air temperature up to some specified temperature limit
above that limit engine operates in such a way that either
fan speed or compressor speed constant or
turbine inlet temperature constant
and in either case thrust then decreases with increasing temperature. 15 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the speed remains constant in flow direction ii the total pressure decreases in flow direction I incorrect ii incorrect. The speed flow reduced static pressure increases dynamic pressure decreases total pressure remains unchanged there no total temperature changes but static temperature increases while dynamic temperature decreases. 16 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the static pressure remains constant in flow direction ii the total temperature decreases in flow direction I incorrect ii incorrect. Static pressure increases dynamic pressure decreases total pressure remains unchanged there no total temperature changes. 17 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the dynamic pressure remains constant in flow direction ii the static temperature remains constant in flow direction I incorrect ii incorrect. Static pressure increases dynamic pressure decreases total pressure remains unchanged there no total temperature changes but static temperature increases while dynamic temperature decreases. 18 Which statement correct about flow in a divergent jet engine inlet i the speed increases in flow direction ii the total pressure increases in flow direction I incorrect ii incorrect. The flow speed decreases static pressure increases dynamic pressure decreases total pressure remains unchanged. 19 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the static pressure decreases in flow direction ii the total temperature increases in flow direction I incorrect ii incorrect. Static pressure increases dynamic pressure decreases total pressure remains unchanged there no total temperature changes but static temperature increases while dynamic temperature decreases. 20 Which of following statements correct about flow in a divergent subsonic gas turbine engine intake i the dynamic pressure increases in flow direction ii the static temperature decreases in flow direction I incorrect ii incorrect. Static pressure increases dynamic pressure decreases total pressure remains unchanged there no total temperature changes but static temperature increases while dynamic temperature decreases. Exclusive rights: Content under private and protected license, reproduction prohibited and prosecuted.
