Book 2 - Combustion Systems Flashcards
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
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
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
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
after the _________, the compressor air is split __% for initial combustion and __% for cooling
after the DIFFUSER, the compressor air is split 20% for initial combustion and 80% for cooling
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
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
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 _______
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
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
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
what are the four main types of combustion system?
- multiple chamber
- tubo-annular (can-annular)
- annular
- reverse flow
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 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
a tubo-annular (____-_______) combustion system, incorporates individual _____-_____ but they are encapsulated within an ________ air casing
a tubo-annular (CAN-ANNULAR) combustion system, incorporates individual FLAME-TUBES but they are encapsulated within an ANNULAR air casing
annular combustion systems consist of a ______ single chamber. annular inner and outer air _______ are fitted and annular inner and outer _______ tubes
annular combustion systems consist of a ANNULAR single chamber. annular inner and outer air CASINGS are fitted and annular inner and outer FLAME tubes
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 ________
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
reverse flow combustion provides the advantage of ________ the length of the engine as combustion chamber can be wrapped around _______ assembly
reverse flow combustion provides the advantage of REDUCING the length of the engine as combustion chamber can be wrapped around TURBINE assembly
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
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
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
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
the combustion efficiency of most gas turbine engines at sea level conditions is ___%
the combustion efficiency of most gas turbine engines at sea level conditions is 100%
