What is the purpose of the combustor and what are its key requirements?

The combustor burns fuel with compressed air to add energy to the flow, raising temperature to 1600-2000K for turbine entry. Key requirements include: high combustion efficiency (>99%), stable flame over wide operating range, low pressure loss (3-6%), uniform temperature profile to protect turbine, reliable ignition, low emissions (NOx, CO, smoke), and durability despite extreme conditions. Combustor types include can, annular, and can-annular designs. The air-fuel ratio is overall lean (60:1) but combustion occurs in a rich primary zone with subsequent dilution and mixing.