Aerothermal Propulsion

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Aerothermal Propulsion

• Lecture 27
• Ramjet Combustion and Flow

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Talos Missile
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Agenda

• On Avoiding shocking in combustion
• Combustion In a Ramjet
• Change in quantities

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Optimized Ramjet
Combustion chamber
nozzle
diffuser
Supersonic compression
subsonic compression
Combustion
expansion
a
1.
2.
3.
6.
5.
4.
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Stagnation Quantities
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Stagnation Quantities
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Stagnation Quantities
We want to preserve Stagnation pressure
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Combustion

• Combustion raises the stagnation temperature of
  the gas
• Combustion can lower stagnation pressure

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Adiabatic Combustion
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Combusting Flow
M? 1 in combusting lows
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Avoiding Shocks

• Combustion must be done so as to keep Mlt1 in flow
• Too high of heating results in shock wave
  formation
• Shock waves create stagnation pressure loss

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Shocks in pipe
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Shocks in pipe
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Shocks in pipe
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Converging-Diverging Nozzle
Mgt1 expanding flow
Converging flow
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Constant Area Flow
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Constant Area Burn
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Area in a Nozzle
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Area in a Nozzle
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Area in a Nozzle
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Area in a Nozzle
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Area in a Nozzle
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Area in a Nozzle
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Converging-Diverging Nozzle
subsonic flow
Supersonic flow
M1
Mgt1 expanding flow
Mlt1
AreaA
AreaA o
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Variation of Nozzle Parameters
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Sonic Conditions
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Sonic Conditions
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Ramjet Nozzles
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Shock diamonds
Supersonic flow encounters ambient air