To prevent vapor lock in fuel lines at high altitude, some aircraft are equipped with

Question

BlackTom AI · Accepted Answer

Lower ambient pressure at altitude reduces the boiling point of aviation gasoline; when local fuel pressure in a line falls to the fuel’s vapor pressure, vapor bubbles form and interrupt flow—a condition called vapor lock. A booster pump prevents this by maintaining a positive, above-vapor-pressure liquid head in the fuel lines so fuel cannot flash to vapor under reduced ambient pressure.

Relevant concepts:
- Vapor pressure and boiling point: as ambient (surrounding) pressure falls with altitude, the temperature at which a liquid boils also falls.  
- Vapor lock: occurs when fuel vaporizes in the line and pumps or carburetors cannot move liquid fuel.  
- Booster (auxiliary) pump function: provides continuous positive pressure downstream of the tank/system, preventing pressure from dropping to the fuel’s vapor pressure.

Step-by-step reasoning:
1. At higher altitude, ambient pressure decreases, lowering the pressure surrounding fuel lines and reducing the margin between line pressure and the fuel’s vapor pressure.  
2. Any localized pressure drop (from engine-driven pump cavitation, long suction lines, or warm fuel) can let fuel vaporize in the line.  
3. Installing an engine-driven or auxiliary booster pump pressurizes the fuel supply so the line pressure remains higher than the fuel vapor pressure even at altitude.  
4. With liquid fuel maintained under pressure, vapor bubbles cannot form and continuous flow to the engine is preserved.

Why the correct answer is correct:
Booster pumps actively raise and sustain fuel-line pressure, directly addressing the cause of vapor lock (fuel vaporization in the line). They are a standard aircraft solution for high-altitude operation.

Why other remedies are less directly effective:
- Simply heating or cooling fuel, fuel return lines, or switching to different carburetion methods may mitigate but do not as reliably maintain positive line pressure as a booster pump.  
- Pressurizing tanks or relying only on gravity feed may not prevent local vapor formation in long or low-pressure runs.

Conclusion: Booster pumps. This confirms the provided correct answer: booster pumps.

To prevent vapor lock in fuel lines at high altitude, some aircraft are equipped with单项选择题

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To prevent vapor lock in fuel lines at high altitude, some aircraft are equipped with单项选择题

类似问题

What is the main way a siphon-feed spray gun draws paint up into the gun for spraying?

The presence of fuel stains around a fuel nozzle would indicate

Fuel is moved overboard in most fuel jettison systems by

A constant-area tank has A=2.20 m^2. The initial height is h0​=0.35 m and the final height is h=0.60 m. The inlet flow rate is Qin​=15.5 L/min and the outlet flow rate is Qout​=6.5 L/min. How long does it take to reach the final height?

4. Which of the following statements best explains the priority behind integrating ventilation systems in fire safety design?

The main metering jet in a carburetor controls fuel flow based on:

A 3/8 inch aircraft high pressure flexible hose as compared to 3/8 inch metal tubing used in the same system will

A 3/8 inch aircraft high pressure flexible hose as compared to 3/8 inch metal tubing used in the same system will

更多留学生实用工具

希望你的学习变得更简单

A constant-area tank has A=2.20 m^2. The initial height is h0=0.35 m and the final height is h=0.60 m. The inlet flow rate is Qin=15.5 L/min and the outlet flow rate is Qout=6.5 L/min. How long does it take to reach the final height?