Untitled - Aerobib - Universidad Politécnica de Madrid

Chapter 11
Similarity in combustion.
Applications
11.1 Introduction
The methods of dimensional analysis and physical similarity have been applied with
very good results to the study, both theoretical and experimental, of classical Aerothermodynamics.
Recently, numerous attempts have been made to extend these methods
to the study of Aerothermochemistry. In some instances, like in the work by Schultz-
Grunow listed in Ref. [1], such an extension was intended in order to facilitate the
establishment of a correlation between several experimental results. Other attempts
tried to find a rational basis for the experimentation with models as well as rules to
apply the results obtained through such models to the processes at normal scale.
Before treating a problem of this nature, it is necessary to determine the dimensionless
parameters that characterize the process. In the phenomena whose study
is the purpose of Aerothermochemistry, such parameters are the same studied by classical
Aerothermodynamics, but increased by the chemical parameters introduced by
Damköhler [2] when he applied physical similarity to the study of chemical reactors.
We owe to Penner [3] the first study on the application of the laws of physical similarity
to Aerothermochemistry. A concise work on the subject, analyzing the origin
and significance of these parameters, is own to von Kármán and listed in Ref. [4].
Recently, Weller [5] has performed a review of the practical applications. Several applications
of this theory to the study of technological problem of combustion will be
found in Penner’s work and in the corresponding sections of the Proceedings of Sixth
International Symposium on Combustion and of Second Colloquium on Combustion,
AGARD.
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