Analysis of liquid rocket combustion chamber turbulence levels from diffusion data

Abstract

The intensity of turbulence and the Lagrangian correlation coefficient in a liquid rocket combustion chamber have been analytically determined from an analysis of experimental diffusion data taken in a small rocket engine, which operated at 300 psia chamber pressure and produced approximately 250 pounds thrust 1 1 The experimental and analytical phases of this work were sponsored by NASA Lewis Research Center GRANT NGR-19-002-030, Richard J. Priem, Project Manager. . The results of gas sample measurements obtained from Orsat and gas chromatograph techniques to determine helium concentration profiles were analyzed by G.I. Taylor's turbulent diffusion theory to obtain turbulence flow field parameters. The results of the analysis indicate that turbulent diffusion in a combustion chamber can be adequately modeled by the one dimensionl Taylor theory which assumes that the intensity of turbulence is a function only of axial distance in the chamber and that the Lagrangian correlation coefficient is of the form e − ατ , where τ is the dispersion time and α is a constant. The results indicate a higher intensity of turbulence and lower correlation than previously expected.