- Author
- Gouldin, F. C.
- Title
- Temperature Measurement in Metal-Combustion: The Calcium-Oxygen Flame.
- Coporate
- Princeton Univ., NJ
- Sponsor
- National Aeronautics and Space Administration, Washington, DC
- Report
- THESIS, May 1970, 333 p.
- Keywords
- temperature measurement | metal combustion | vapor phases | flame temperature | equations | combustion | electronic equipment | thermodynamics | metal oxide | boiling point
- Identifiers
- adiabatic flame temperatures and relevant thermodynamic data; experimental apparatus and procedure; analytical developments; solution of the equation of transfer; scattering analysis; equation of transfer and Kirchhoff's Law
- Abstract
- This work contains a study of temperatures in metal-oxygen flames from both theoretical and experimental points of view. Thermodynamic arguments limiting the flame temperature to the boiling point of the metal oxide are discussed from the standpoint of equilibrium and energy. It is argued that in the presence of a diluent the boiling point is not an equilibrium point and the temperature must be lower than the boiling point. In general the boiling point is a theoretical limit to the flame temperature which is rarely obtained in practical flames even when heat loss is negligible. Furthermore, the adiabatic flame temperature is shown by qualitative and quantitative means to be a function of environmental composition and pressure. A method for calculating adiabatic flame temperature is outlined and discussed. Calculated flame temperatures are presented and compared with e experimental results. These calculations revealed adiabatic flame temperature equaled the oxide boiling temperature only for a stoichiometric mixture of metal en in the absence of diluent. As diluent is added the flame temperature decreases with reductions of a few hundred Kelvin occurring for dilution by a factor of 10 or more. The influence of additional oxygen, above stoichiometric, is initially to increase slightly and then decrease the temperature. On the basis of these results it is concluded that in flames where kinetics are unimportant, the flame temperature will be within about 100 deg K of the oxide boiling point. On the other hand, for low pressure metal diffusion flames, where chemistry is important, maximum temperatures will be well below the metal oxide boiling point. The second part of this work is devoted to measuring flame temperature profiles in low pressure calcium-oxygen diffusion flames using an optical technique. Measured temperatures are reported and discussed in terms of the calculated adiabatic flame temperatures and a combustion model proposed recently by Sullivan (1969) which is based on observations made in this laboratory.