L12 - Combustion and Fuels

Question 1

What are some combustor requirements?

Answer 1

High Efficiency 
Smooth ignition
Wide stability limits
Free from pressure pulsations
Low Pressure Loss
Durability

Question 2

What does increasing temperaturs in the chamber do?

Answer 2

Decreases density and increases velocity. Pressure losses increase with V^2

Question 3

What is added to reduce flow velocity?

Answer 3

Diffuser with angle 7-12degs

Question 4

What is required to keep a flame lit?

Answer 4

A baffle, this produced a recirculated region slow enough for constant flame

Question 5

How is air mixed effectively?

Answer 5

By introducting air in stages, through diffusion holes.

Question 6

What are the three main types of combustors? and what industries are they used in?

Answer 6

• Tubular - Industrial
• Annular - Industrial
• Tubular Annular - Industrial

Question 7

What is the aim of the air spray fuel injector?

Answer 7

Highest surface area to mass ratio to allow quick evaoration and subsequent combustion.

Question 8

Is the TET evenly distributed and constant?

Answer 8

No

Question 9

How does loading stress and temperature vary along a turbine blade?

Answer 9

Stress decreases towards tip

Temp increases towards tip

Question 10

What fuel is used in aviation?and why?

Answer 10

Kerosene

High energy density, low freexing point, high combustion temp.