Nozzle Design

By Jon Suzuki

October Sky

• a simple device used to control the characteristics of a fluid as it enters or exits the nozzle.

What Purpose Do Nozzles Serve?

• nozzles control the pressure, speed, direction, temperature, and mass’s rate of flow of the fluid.

What Specifically?

• to maximize the kinetic energy of the fluid by utilizing the heat and pressure in the combustion chamber

The Ultimate Goal

• also known as the convergent-divergent nozzle

The De Laval Nozzle

• developed in 1888 by Swedish engineer Gustaf de Laval for steam turbines.

• utilizes the kinetic energy of the fluid rather than the pressure of the fluid.

• first used in rockets in the early 1900s by Robert H. Goddard, the Father of Modern Rocketry.

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• cone and bell nozzles• small degree cones give a high efficiency

around 95% while larger degree cones offer a lower efficiency.

• bell nozzles give 1-1.5% more efficiency and can also be shorter and lighter however, difficult to fabricate therefore, more expensive.

Optimum Shape

• mass, energy, and momentum are conserved.

• p = mv

How Do Nozzles Work?

• the fluid can be accelerated faster than M = 1 because of the increasing ratio between the area of the throat and the area of the exit

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• is when the exhaust gases at the exit of the nozzle fall below speeds of M = 1 due to the discontinuous ratio of the atmospheric pressure and the combustion chamber pressure.

Nozzle Shock

Shock Wave Graphs

• if the exits pressure is too low compared to the ambient pressure (low altitudes), the jet will separate from the nozzle, which improves efficiency but causes instability due to the overexpanded thrust.

Results

• if the exit pressure is too high compared to the ambient pressure (high altitudes), the jet will expand past the nozzle exit reducing efficiency.

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• to find the one area ratio between the throat and exit of the nozzle that gives the best performance at variable altitude and pressure.

Optimization

• purpose is to have optimum efficiency throughout the mission by compensating for change in altitude resulting change in ambient pressure.

Advanced Nozzles

Expansion - Deflection Plug Nozzle

Aerospike

More DesignsStepped Nozzle

• developed ballistic missiles.

Sergei Korolev

• managed the assembly of Sputnik

• Luna 2• human space flight

(Vostok)

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Bibliography"Sergei Korolev." Wikipedia. Wikimedia Foundation, 26 July 2013. Web. 25 July 2013.

"Nozzle Design." Nozzle Design. N.p., n.d. Web. 25 July 2013.

"Converging Diverging Nozzle." Converging Diverging Nozzle. N.p., n.d. Web. 25 July 2013.

"Rocket Engine Nozzle." Wikipedia. Wikimedia Foundation, 07 Sept. 2013. Web. 25 July 2013."De Laval Nozzle." Wikipedia. Wikimedia Foundation, 22 June 2013. Web. 25 July 2013.

"(26) Robert Goddard and His Rockets." Robert Goddard and His Rockets. N.p., n.d. Web. 25 July 2013.