Structure of Monopropellant Spray Flames at Elevated Pressures
Abstract
The combustion properties of HAN-based monopropellants (LGP1845 and 1846) were studied, considering: liquid surface properties and conditions required for the thermodynamic critical point to be reached, drop combustion properties in combustion gas environments at pressures of 0.2-7.0 MPa, and pressure-atomized spray combustion properties in combustion gas environments at pressures of 3-9 MPa. Computations of liquid surface properties in flame environments indicated unusually high liquid surface temperatures, ca. 1000K, and critical combustion pressures, ca. 250 MPa, since these propellants have thermodynamic properties similar to molten salts. Drop burning was dominated by subsurface reaction leading to bubble formation and microexplosions which mechanically removed liquid, at low pressures (less that 2.1 MPa); and conventional heterogeneous combustion from the surface at high pressures (greater than 2.1 MPa). The resulting apparent burning rates were relatively independent of pressure and were large, ca. 10 mm/s, which is consistent with earlier strand burning rate measurements of jelled propellants at pressures greater than 10 MPa by McBratney (1980, 1981). Measurements of drop size distributions, liquid flow rates, and liquid mass fluxes in combusting sprays were consistent with the individual drop burning rate measurements and exhibited strong effects of separated flow. Keywords: Spray combustion; Liquid propellants; Monopropellant combustion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 1990
- Accession Number
- ADA218676
Entities
People
- Gerard M. Faeth
- L.-k. Tseng
- M. E. Kounalakis
- T.-w. Lee
Organizations
- University of Michigan