Fuel Combustion Quiz - Gas Turbine Powerplants

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Questions and Answers

What is the effective air/fuel ratio for kerosene combustion?

30:1

15:1 (correct)

45:1

150:1

What should be done with Prist or Biopor in fuel management?

It should be flushed out immediately.

It should be stored separately from the fuel.

It should be diluted with water to a 3-1 mix.

It should be burned with the fuel. (correct)

What does D.E.R.D 2494 refer to?

High-octane gasoline

Wide cut gasoline

Diesel fuel

Kerosene (correct)

What does a high viscosity index indicate about oil viscosity?

It will not vary greatly with temperature change. Signup and view all the answers

What is the primary function of a fuel system icing inhibitor?

It prevents the water in the fuel from freezing. Signup and view all the answers

What is the consequence of using a low-temperature lubricant in extremely high temperatures?

The oil pressure will be lower than normal. Signup and view all the answers

What measurement is used to assess the flow rate of oil through an orifice?

Specific gravity Signup and view all the answers

Which of the following is a correct statement about kerosene?

It is mainly used for aviation fuels. Signup and view all the answers

What setting must be adjusted to ensure the validity of a turbine engine performance check when using an alternate fuel?

Fuel specific gravity setting Signup and view all the answers

Why is kerosene preferred over gasoline for turbine engines?

Kerosene is less volatile and has good lubrication properties Signup and view all the answers

What is defined as the amount of heat or energy in one pound of fuel?

Calorific value Signup and view all the answers

How does specific gravity of fuel impact aircraft capabilities?

It influences aircraft range Signup and view all the answers

What type of oil is typically used in gas turbine engines?

Synthetic Signup and view all the answers

What does an oil spectroscope measure?

Contaminants suspended in the oil Signup and view all the answers

What factors does fuel ignition depend on?

Both volatility and atomisation Signup and view all the answers

If the specific gravity of a fuel increases, what happens to the weight of a tank filled with that fuel?

The weight increases Signup and view all the answers

At what temperature is Reid vapor pressure measured?

38°C Signup and view all the answers

What contributes to kerosene being a suitable fuel for engines regarding heat energy?

Kerosene has more heat energy per gallon and lubricates fuel system components Signup and view all the answers

What determines the viscosity index of a lubricating oil?

Its rate of change in viscosity with temperature change. Signup and view all the answers

Which property of turbine engine oils distinguishes them from reciprocating engine oils?

They have less tendency to produce lacquer or coke. Signup and view all the answers

For theoretically perfect engine lubrication, what type of oil should be used?

The thinnest oil that can maintain film strength. Signup and view all the answers

In addition to lubricating, what other functions does engine oil perform?

It cools, seals, prevents corrosion, and cushions shock loads. Signup and view all the answers

Which factor is important in determining the proper grade of oil for an engine?

Operating speeds of bearings. Signup and view all the answers

What does specific gravity compare?

Weight of a substance to the weight of an equal volume of distilled water. Signup and view all the answers

What advantage do mineral-based lubricants have over vegetable oil-based lubricants in aircraft engines?

Greater chemical stability. Signup and view all the answers

What type of lubricant is necessary for high-pressure spur type gears?

An E.P lubricant. Signup and view all the answers

Which characteristic is desirable in turbine engine oil?

High flash point. Signup and view all the answers

What action is taken to protect integral fuel tanks from microbiological contamination?

A biocidal additive is introduced into the fuel. Signup and view all the answers

Study Notes

Kerosene and Fuel Properties

Kerosene burns effectively at an air/fuel ratio of 15:1.
D.E.R.D 2494 refers to a type of kerosene used in specific aviation applications.
Kerosene serves as turbine engine fuel due to its higher heat energy per gallon and ability to lubricate fuel system components.

Fuel Additives and Functions

Prist or Biopor is used with fuel and is not flushed out but left to burn, helping in fuel system maintenance.
Fuel system icing inhibitors prevent water in the fuel from freezing, ensuring safe operation in colder temperatures.

Lubrication and Engine Oil Properties

High viscosity index indicates that oil viscosity will not change significantly with temperature fluctuations.
Engine oil performs multiple functions including cooling, sealing, preventing corrosion, and cushioning shock loads.
The viscosity of a liquid is a measure of its resistance to flow, critical for engine performance.

Engine Performance Considerations

Operating speeds of bearings help determine the appropriate grade of oil for various engines.
Oil used in gas turbine engines is typically synthetic, enhancing performance and durability.
Specific gravity affects aircraft range; greater density at fixed volume leads to increased fuel weight and range.

Measurement and Evaluation

The time for oil to flow through a calibrated orifice measures its viscosity; faster flow indicates lower viscosity.
Oil spectroscopes measure contaminants suspended within the oil, important for maintenance and performance checks.

Fuel Characteristics

Ignition of fuel involves both volatility (ease of vaporization) and atomization (splitting into fine particles), crucial for effective combustion.
Kerosene is favored over gasoline due to its lower volatility and superior lubrication qualities, making it safer for storage and handling.

Additional Characteristics

Reid vapor pressure quantifies the vapor pressure exerted by fuel at 38°C, relevant for assessing fuel volatility under varying temperatures.
Cooling ability, chemical stability, and less tendency to produce lacquer or coke are key characteristics of mineral bases over vegetable oil bases for aircraft lubrication.

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Description

Test your knowledge on fuel combustion ratios and additives used in gas turbine powerplants. This quiz covers questions related to air/fuel ratios and specific practices regarding fuel treatment. Suitable for students studying turbine technology or related engineering fields.