In order to model a practical combustion system successfully, it is necessary to develop one or more reaction rate equations which will describe performance over a wide range of conditions. The equations should be kept as simple as possible and commensurate with the accuracy needed. In this paper a bimolecular reaction is assumed, based upon a simple mass balance. Temperatures derived from the latter are related to measured practical ones such that, if required, an evaluation of the partly burned product composition can be made. A convenient reaction rate equation is given which describes a wide range of blow-out data for spherical reactors at weak mixture conditions. NVP2φ={1.29×1010(m+1)[5(1−yε)]φ[φ−yε]φe−C/(Ti+εΔT)}/{0.082062φyε[5(m+1)+φ+yε]2φ[Ti+εΔT]2φ−0.5} Analysis of the components used in the above equation (especially the variation of activation energy) clearly shows its empirical nature but does not detract from its engineering value. Rich mixtures are considered also, but lack of data precludes a reliable analysis. One of the major results obtained is the variation of the reaction order (n) with equivalence ratio (φ): weak mixtures, n = 2φ; rich mixtures, n = 2/φ. Some support for this variation has been noticed in published literature of other workers.

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A small combustor of normal design employing acoustic control of the dilution-air flows has been successfully tested up to “half-load” conditions. It has been shown that this technique can be used to control the exit plane temperature distribution; also the ability to trim the temperature profile has been convincingly demonstrated. The acoustic driver power requirements were minimal, indicating that driver power at “full-load” will not be excessive. The nature of the acoustically modulated dilution-air flows has been clearly established as that of a pulsating jet flow with superimposed toroidal vortices. The pressure loss of the unit and its combustion efficiency were insignificantly affected by the acoustic drive. The work contributes to the design of combustors such that a desired exit plane temperature distribution may be achieved.

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The cited method predicts wall temperatures generally within an accuracy of f 6 percent. The biggest single factor governing the wall temperature is shown to be the hot gas temperature. Other factors discussed are the effects of changes in inlet temperature, fuel types, the geometry of the film cooling devices and manufacturing tolerances. Empirical formulas are given for the prediction of effective temperatures within the various combustor zones. Some comparisons are made between predictions and measurements of wall temperatures over a range of operating conditions.