Boron and polytetrafluoroethylene as a fuel composition for hybrid rocket applications

Terrence Lee Connell, Jr., Grant Alexander Risha, Richard A. Yetter, Colin W. Roberts, Gregory Young

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Acomposition consisting of 80% polytetrafluoroethylene and 20% boron (by weight) was considered as a potential high-density solid fuel mixture for mixed hybrid rocket propulsive applications. Constant-pressure strand burner experiments for the given formulation indicated a low-pressure self-deflagration limit of approximately 2.2 MPa (319 psia), and a burning rate correlation rb[cm/s] = 0.042[P/MPa]/0.531 was determined. Pressurized counterflow burner experiments conducted using pure oxygen revealed formation of surface char, which prevented measurement of solid fuel regression rates below 2 MPa, indicating an additional resistance for heat and mass transfer. Static-fired rocket motor experiments, conducted to determine the pressure and flow dependencies of the system, exhibited characteristic exhaust velocity efficiencies ranging from approximately 86 to 96%.Whereas classical hybrids do not have a strong dependence of fuel regression rate on pressure, a pressure dependence was observed in this system below the low-pressure self-deflagration limit due to the pressure dependence of the decomposition and fluorination kinetics of the solid fuel mixture. Below the low-pressure self-deflagration limit, the motor operated at a constant pressure, typical of a classical hybrid, whereas above the limit, a progressive burn was observed, characteristic of a composite propellant. Systematic oxidizer dilution with nitrogen revealed a decrease in pressurization rate with decreasing oxygen content, and an ignition limit was achieved for this system when the oxygen mass fraction was reduced from 0.65 to 0.6. Characteristic exhaust velocity efficiencies were not noticeably affected by oxidizer dilution with nitrogen over the range considered.

Original languageEnglish (US)
Pages (from-to)373-385
Number of pages13
JournalJournal of Propulsion and Power
Volume31
Issue number1
DOIs
StatePublished - Jan 1 2015

Fingerprint

polytetrafluoroethylene
Rockets
rockets
Polytetrafluoroethylenes
boron
deflagration
Boron
exhaust velocity
oxidizers
low pressure
burners
Chemical analysis
pressure dependence
dilution
regression analysis
oxygen
ignition limits
composite propellants
nitrogen
burning rate

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Fuel Technology
  • Mechanical Engineering
  • Space and Planetary Science

Cite this

Connell, Jr., Terrence Lee ; Risha, Grant Alexander ; Yetter, Richard A. ; Roberts, Colin W. ; Young, Gregory. / Boron and polytetrafluoroethylene as a fuel composition for hybrid rocket applications. In: Journal of Propulsion and Power. 2015 ; Vol. 31, No. 1. pp. 373-385.
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Boron and polytetrafluoroethylene as a fuel composition for hybrid rocket applications. / Connell, Jr., Terrence Lee; Risha, Grant Alexander; Yetter, Richard A.; Roberts, Colin W.; Young, Gregory.

In: Journal of Propulsion and Power, Vol. 31, No. 1, 01.01.2015, p. 373-385.

Research output: Contribution to journalArticle

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