• Version
• 39 Downloads
• 1.15 MB File Size
• 1 File Count
• April 21, 2017 Create Date
• April 21, 2017 Last Updated

National Advisory Committee for Aeronautics, Research Memorandum - Preliminary Correlation of Efficiency of Aircraft Gas-Turbine Combustors for Different Operating Conditions

An empirical correlation is presented of the combustion-
efficiency data previously obtained in experimental investigations
with 14 aircraft gas-turbine combustors. The precision of the cor-
relations is not good for some of the combustors. The correlations
are of value, however, in predicting the efficiency at different
operating conditions and in comparing the performance of different
combustors from data obtained in unrelated tests.

A theoretical analysis based on the kinetics of a bimolecular
chemical reaction is also presented which, with additional assump-
tions regarding the mechanism of the combustion process, yields the
correlation parameter previously obtained by empirical means. The
theoretical analysis yields equations that predict the shape of the
curves obtained by plotting the experimental data.

Investigations of the performance of various gas—turbine comr
bustors at the NACA Lewis laboratory have yielded a large amount of
combustor performance data, but no method has been presented for
correlating these data in terms of fundamental parameters. Refer-
ence 1 showed that combustion efficiendy and maximum obtainable
temperature rise were decreased by a decrease in combustor-inlet
pressure or temperature and by an increase in combustor-inlet
velocity. No parameter was expressed, however, for combining these
effects to make possible a prediction of combustor performance for
any given operating conditions.

A parameter was derived by empirical methods which served to
correlate these data, and the correlations are presented herein.
A theoretical analysis of the combustion process was also made to
illustrate that the empirically-derived parameter could also be
derived from a theoretical approach. This work was carried out
simultaneously with the experimental phases of the research. The
theoretical analysis and methods of correlating combustor perform-
ance data that are presented in this report were arrived at as
early as 1944. Attempts to refine the analysis and the use of
entirely different theoretical analyses have failed to yield a
better means of correlating the experimental data. The method of
correlating combustor performance data that is presented herein
is therefore as good as could readily be achieved with presently
available experimental data and with the present knowledge of the
combustion process.