Jet engines: operating condition for higher propulsive efficiency. Determine at which operating regime a jet engine attains higher propulsive efficiency relative to low-speed operation. Select the best option.
Mechanical Engineering
Compressors, Gas Dynamics and Gas Turbines
Difficulty: Easy
Choose an option
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Alow speeds
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Bhigh speeds
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Clow altitudes
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Dhigh altitudes
Answer
Correct Answer: high speeds
Explanation
Concept/ApproachPropulsive efficiency depends on how closely the jet velocity matches the flight speed. For pure jets, efficiency increases with aircraft speed (up to practical limits), since less kinetic energy is wasted in the exhaust stream for a given thrust.
Final Answerhigh speeds.