Before we can move on to describe how the various parts of a jet engine do their job, we have to understand a little bit about how air behaves when subjected to certain forces.
Pressure, Velocity and Temperature
When air moves through a straight pipe or passage, the pressure, velocity and temperature will remain constant.
When air moves through a pipe or passage with a decreasing area (a convergent duct) the velocity of the air will increase but the pressure and temperature of the air will decrease.
When air moves through a pipe or passage with an increasing area (a divergent duct) the velocity of the air will decrease but the pressure and temperature of the air will increase.
The jet engine makes use of convergent and divergent ducts to control the pressure and velocity of the air so it is quite important to explain this point now.
Convergent Duct
Divergent Duct
Reproduced with kind permission of Rolls-Royce plc
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Before we can move on to describe how the various parts of a jet engine do their job, we have to understand a little bit about how air behaves when subjected to certain forces.
Pressure, Velocity and Temperature
When air moves through a straight pipe or passage, the pressure, velocity and temperature will remain constant.
When air moves through a pipe or passage with a decreasing area (a convergent duct) the velocity of the air will increase but the pressure and temperature of the air will decrease.
When air moves through a pipe or passage with an increasing area (a divergent duct) the velocity of the air will decrease but the pressure and temperature of the air will increase.
The jet engine makes use of convergent and divergent ducts to control the pressure and velocity of the air so it is quite important to explain this point now.