Page 52 - The Jet Engine
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Combustion chambers
Fig. 4-9 Annular combustion chamber.
and compact gas turbine combustion chamber must another way this is an expenditure of potential heat
release heat at exceptionally high rates. at a rate equivalent to approximately 150,000 horse-
power.
26. For example, at take-off conditions a Rolls-
Royce RB211-524 engine will consume 20,635 lb. of Combustion efficiency
fuel per hour. The fuel has a calorific value of approx- 27. The combustion efficiency of most gas turbine
imately 18,550 British thermal units per lb., therefore engines at sea-level take-off conditions is almost 100
the combustion chamber releases nearly 106,300 per cent, reducing to 98 per cent at altitude cruise
British thermal units per second. Expressed in conditions, as shown in fig. 4-10.
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