Turbine Combustion Chamber

HelloI am actually teaching physical science at an online school, and came across this issue in the textbook - In one chapter of the physical science text it includes this text about gas turbines:THE GAS TURBINEAnother type of internal-combustion engine is called a gas turbine. The main parts of this engine are represented in Figure 26. Air is fed through the inlet pipe into a set of rotating blades in the compressor. The compressed air passes through the pipe to the oil-burning chamber. Fuel oil from the pump is furnished to the oil-burning chamber, where it�s mixed with some of the compressed air from the pipe. This mixture is then ignited and burned in the chamber. The rest of the compressed air is fed through an air passage to the combustion chamber. In the combustion chamber, the air mixes with the gaseous products of combustion and cools these gases to a suitable temperature for use in the turbine wheel.... with this diagram:https://drive.google.com/file/d/0Bzpz5UtYxWMbUUNzdWo4NS1MQ1MyM2lKOWM5SWhwYXEyZXkw/view?usp=sharingThe text and diagram and even a test question states that the combustion chamber is not for burning anything but is separate from the oil burner and is used for cooling combustion products to a suitable temperature. Is this correct? Diagrams from other sources show the combustion actually happening in the combustion chamber. Is my textbook wrong or just unclear?Thank you for your help!
- Laura (age 28)
Pennsylvania, USA

We aren't experts on this. Still, looking over the various illustrations available on the Web, as you say others show that the burning zone in the combustion chamber gradually fades downstream into a mixing/cooling zone, without a sharp boundary. It's possible that the author of your textbook mixed up the small part where the fuel is injected with the larger volume where it burns. We've definitely found mistakes in textbooks before, and we've made mistakes ourselves on this site. 

Mike W.

(published on 01/06/2016)