Combustion of aluminum in solid rocket motor flows

John C. Melcher, Jason T. Brzozowski, Herman Krier, Rodney L. Burton

Research output: Contribution to conferencePaperpeer-review


The combustion of aluminum droplets was studied in a solid-rocket chamber flow-field with variable chamber pressure. Rocket motor chamber conditions were generated directly from an aluminized solid propellant combustion products flow field. The experimental test conditions were 1-20 atm pressure and ~2300. K temperature. Images of the burning aluminum droplets were made with a high-speed CCD video camera, and were de-convoluted with an Abel transformation to give radial intensity profiles of the flame and A12O3 smoke cloud surrounding each droplet. High-magnification experiments have shown major differences in the combustion of aluminum between well-studied 1 atm cold air environments and solid rocket motor conditions. The aluminum droplet flame burns with a much greater intensity at chamber pressures, indicating an increase in flame temperature, and the flame/Al2O3 cloud region thickens and extends close to the droplet surface, possibly indicating a reaction-limited mechanism in the H2O/CO2 environment. The mean value for the location of the peak intensity in the flame/Al2O3 cloud region is (rPeak/rsurf) ~ 2.5, and there was no apparent correlation between flame/Al2O3 smoke size and chamber pressure. However, as droplet diameter decreases, the overall A12O3 smoke cloud size increases, indicating a reaction-limited system becoming more fuel-lean as the droplet surface area decreases. Lastly, studies were conducted to observe combustion events at the surface of the aluminized propellant. Aluminum particles were first almost fully 'cleaned' before ignition began, but there was still enough binder to hold the aluminum particles onto the surface during ignition, which can lead to agglomeration.

Original languageEnglish (US)
StatePublished - 2000
Externally publishedYes
Event36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2000 - Huntsville, AL, United States
Duration: Jul 16 2000Jul 19 2000


Other36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2000
Country/TerritoryUnited States
CityHuntsville, AL

ASJC Scopus subject areas

  • Space and Planetary Science
  • Energy Engineering and Power Technology
  • Aerospace Engineering
  • Control and Systems Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering


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