Characterization of Polyoxymethylene as a High-Density Fuel For Use in Hybrid Rocket Applications

Open Access
Author:
Talamantes, Gerardo
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 08, 2019
Committee Members:
  • Richard A Yetter, Thesis Advisor
  • Stefan Thynell, Committee Member
  • Daniel Connell Haworth, Committee Member
Keywords:
  • Solid Fuels
  • Polyoxymethylene
  • Diffusion Flame
  • Opposed Flow Burner
  • Hybrid Rockets
  • High-Density Fuel
  • POM
  • combustion
Abstract:
Experimental testing was conducted to investigate the behavior of polyoxymethylene (POM) for consideration as the solid fuel component in an upper stage hybrid rocket engine using high-density fuel and oxidizer. The regression rate of POM was experimentally measured using an opposed flow burner to determine the influence of color, oxidizer type, and nozzle separation distance on regression rate. The experimental measurements of regression rate on POM were compared to numerical findings that were obtained using a kinetic model developed for POM combustion in a counter-flowing geometry. It was found that natural vs. black POM does not influence the regression rate when measured in the opposed flow burner. The numerical findings were found to be consistent with the observed trends for all strain rates showing the fuel regression rate to increase with increasing oxidizer flow velocity. However, at smaller separation distances the experimental and numerical regression rates varied due to non-uniform burning surface characteristics breaking down the 1-D assumptions of the model. Numerical calculations were also performed at pressures from 0.1 MPa to 7 MPa and showed an increase in fuel regression rate due to the momentum flux of oxidizer increasing at a greater rate than momentum flux of the fuel with pressure, thus moving the flame closer to the fuel surface. POM combustion was also compared to hydroxyl-terminated polybutadiene (HTPB) combustion and was found to have similar linear regression rates with a 50% mass flux increase of POM due to increased density.