Book 2 - Combustion Systems Flashcards Preview

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Flashcards in Book 2 - Combustion Systems Deck (17)
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1
Q

very high temperatures exist in the combustion system, the burning temperature of the fuel being approximately ____ celsius. to protect the material from which the system is manufactured, approximately __% of the air flow after the _________ is used for cooling

A

very high temperatures exist in the combustion system, the burning temperature of the fuel being approximately 2000 celsius. to protect the material from which the system is manufactured, approximately 80% of the air flow after the DIFFUSER is used for cooling

2
Q

the combustion process requires __lbs of air to _lb of fuel for _______ combustion. this is known as an air/fuel ______ of 15:1 by weight

as a large proportion of the air is used for cooling, the ratio of air to fuel can be between __:1 and ___:1 over the engine RPM range

A

the combustion process requires 15lbs of air to 1lb of fuel for COMPLETE combustion. this is known as an air/fuel RATIO of 15:1 by weight

as a large proportion of the air is used for cooling, the ratio of air to fuel can be between 45:1 and 130:1 over the engine RPM range

3
Q

after the _________, the compressor air is split __% for initial combustion and __% for cooling

A

after the DIFFUSER, the compressor air is split 20% for initial combustion and 80% for cooling

4
Q

the air used for combustion is further split, with approximately __% of the total airflow passing through ______ vanes. the swirl helps promote initial combustion and _______ the flame at the combustion chamber snout

A

the air used for combustion is further split, with approximately 12% of the total airflow passing through SWIRL vanes. the swirl helps promote initial combustion and ANCHOR the flame at the combustion chamber snout

5
Q

the 80% of air flow used for cooling is split into three zones:

  • primary air flow - for mixing with ____ and to support combustion
  • secondary air flow - to shape the flame and ________ combustion
  • tertiary air flow - to cut off the flame and _______ gas temperature to a figure acceptable to the _______
A

the 80% of air flow used for cooling is split into three zones:

  • primary air flow - for mixing with FUEL and to support combustion
  • secondary air flow - to shape the flame and COMPLETE combustion
  • tertiary air flow - to cut off the flame and REDUCE gas temperature to a figure acceptable to the TURBINE
6
Q

secondary and tertiary cooling air forms a _________ flow on the inside and outside of the flame tube, which is manufactured from special heat resistant (________) steel, the air casing made from aluminised steel

A

secondary and tertiary cooling air forms a BOUNDARY flow on the inside and outside of the flame tube, which is manufactured from special heat resistant (NIMONIC) steel, the air casing made from aluminised steel

7
Q

what are the four main types of combustion system?

A
  • multiple chamber
  • tubo-annular (can-annular)
  • annular
  • reverse flow
8
Q

a multiple chamber combustion system consists of a number of __________ chambers which form a circle around the spine of the engine. the chambers are interconnected to help _________ the pressure generated throughout the system during combustion

A

a multiple chamber combustion system consists of a number of INTERCONNECTED chambers which form a circle around the spine of the engine. the chambers are interconnected to help EQUALISE the pressure generated throughout the system during combustion

9
Q

a tubo-annular (____-_______) combustion system, incorporates individual _____-_____ but they are encapsulated within an ________ air casing

A

a tubo-annular (CAN-ANNULAR) combustion system, incorporates individual FLAME-TUBES but they are encapsulated within an ANNULAR air casing

10
Q

annular combustion systems consist of a ______ single chamber. annular inner and outer air _______ are fitted and annular inner and outer _______ tubes

A

annular combustion systems consist of a ANNULAR single chamber. annular inner and outer air CASINGS are fitted and annular inner and outer FLAME tubes

11
Q

in summary:

  • multiple cans combustion - _____ design, bulky but simple to _________ and service
  • tubo-annular combustion - some advantages of multiple can but _______ frontal area, with _______ exterior and _______ weight
  • annular combustion - ____ compact, shorter with _____ output and mass flow, allow more ________ and better airflow into ________
A

in summary:

  • multiple cans combustion - EARLY design, bulky but simple to DISASSEMBLE and service
  • tubo-annular combustion - some advantages of multiple can but REDUCED frontal area, with SMOOTH exterior and REDUCED weight
  • annular combustion - MORE compact, shorter with EUQAL output and mass flow, allow more BURNERS and better airflow into TURBINE
12
Q

reverse flow combustion provides the advantage of ________ the length of the engine as combustion chamber can be wrapped around _______ assembly

A

reverse flow combustion provides the advantage of REDUCING the length of the engine as combustion chamber can be wrapped around TURBINE assembly

13
Q

the compressor delivery air used for _______-skinned combustion liner cooling enters through four different types of liner design, which are:

  • __________-strip cooling
  • _________ cooling ring
  • ______ cooling strip
  • ___________ cooling
A

the compressor delivery air used for DOUBLE-skinned combustion liner cooling enters through four different types of liner design, which are:

  • CORRUGATED-strip cooling
  • MACHINED cooling ring
  • SPLASH cooling strip
  • TRANSPIRATION cooling
14
Q

cooling air for combustion also supports __________ and shapes the ______. this is to ensure that:

  • the flame is not __________
  • the pressure _____ across the liner is maintained at a satisfactory level at all conditions
A

cooling air for combustion also supports COMBUSTION and shapes the FLAME. this is to ensure that:

  • the flame is not DISTORTED
  • the pressure DROP across the liner is maintained at a satisfactory level at all conditions
15
Q

the combustion efficiency of most gas turbine engines at sea level conditions is ___%

A

the combustion efficiency of most gas turbine engines at sea level conditions is 100%

16
Q

smoke represents an almost negligible loss in combustion efficiency of less than 0._%

A

smoke represents an almost negligible loss in combustion efficiency of less than 0.3%

17
Q

what are the harmful by-products of combustion? (4)

A
  • carbon deposits
  • carbon monoxide
  • hydrocarbons
  • smoke