Student: C1C Tim Brown

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Fast Burning Hybrid Fuels

• Student C1C Tim Brown
• Advisor Maj. Lydon

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Preview

• Motivation
• Fuel Burning Theory
• Objectives
• Predictions
• Cavitating Venturi
• Experimental Test Set-Up
• Results
• Conclusions

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Motivation

• There is growing emphasis on safety,
  environmental cleanliness, low cost, and safety .
• Hybrids suffer from low regression rates

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Fuel burning theory
Humble, R. W., Henry, G, N., Larson, W, J., Space
Propulsion Analysis and Design, Space Technology
Series, McGraw-Hill Companies, Inc.,1995.
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Objectives

• Vary oxidizer mass flow rates to find any
  oxidizer mass flow dependency
• Test the hypothesis that paraffin wax offers high
  regression potential due to droplets which
  readily escape from a liquid layer on the surface
  into the flame zone where they can react with
  hydrogen peroxide
• Calculate a and n from the following equation

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Predictions
A thermochemistry computer code provided our
starting point. Assume frozen flow, exit
pressure of 82.7 kPa, 90 pure HTP, 95 paraffin
wax and 5 carbon black One test for each
different chamber pressure Gave optimum O/F
ratio and predicted Isp
GuiPep, Arthur J. Lekstutis, Traxel Labs Inc.,
Revision 0.04
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Predictions

• Thrust is adjusted to optimize fuel geometry.
• Oxidizer mass flow rate is calculated from
• c is calculated from the thermochemistry
  computer code where Isp is greatest.
• Chamber pressures are based on oxidizer mass flow
  rates
• Length is calculated from cylinder geometry

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Predictions
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Cavitating Venturi

• To ensure that the mass flow rates of oxidizer
  were as desired during the experiment the
  cavitating venturi was calibrated at varying
  pressures using H20.

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Experimental Test Set-up
2,000 psi nitrogen tank Water-cooled
nozzle Purge system Oxidizer Fuel cartridges
easily exchanged Spacer Data acquisition at
1,000 Hz
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Experimental Test Set-Up
Pressure transducers were inserted pre-CV,
post-CV, and chamber
The nozzle had a 1.1075 square inch exit area
and a .1104 square inch throat area yielding
an expansion ratio of 10.03.
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Results
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Results
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Results
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Results
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(No Transcript)
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Conclusion

• Similar tests conducted by Stanford University
  using gaseous oxygen as the oxidizer achieved
  regression rates around 2.6 mm/sec for values of
  130 kg/m2-sec. Our regression rate is closer to
  3.23 mm/sec for the value of 130 kg/m2-sec.
  The hypothesis that paraffin is capable of a high
  regression rate, especially with hydrogen
  peroxide, was validated.

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Conclusion

• The main shortcomings were lower than expected
  , , and c.
• Difficulty of recovering specimens weight after
  firing as well as calculating web-thickness.
  Therefore included a 5 loss regression result
  which is still above expected

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Questions?