MEASUREMENTS OF TURBULENCE STATISTICS AND ENERGY BUDGETS IN A MODEL COMBUSTOR

Simultaneous two-component laser-Doppler-velocimeter measurements were made in an axisymmetric sudden expansion to measure the flow properti es of a confined, isothermal flowfield of a research dump combustor. M easurements of mean velocities, Reynolds stresses, and triple products were carried out at axial distances ranging from 0.38H (H = step heig ht) to 18H downstream of the dump plane. Detailed experimental data ar e provided to help in understanding the behavior of turbulent transpor t characteristics of the confined shear layer. Data from this study co uld be used to upgrade or evaluate advanced numerical codes used to pr edict complex turbulent flows. The turbulent kinetic energy terms (i.e . convection, diffusion, and production terms) were computed directly from the experimental data using central differences, while the viscou s dissipation term was obtained from the energy balance equation. Deta iled comparison of the present data with similar work shows that the g eneral behavior of the flow-field and energy budget results are in exc ellent agreement. The shear-layer flow created by sudden expansion enh ances combustor performance by serving as a turbulence generator mecha nism. (C) 1998 Elsevier Science Ltd. All rights reserved.