Measurements and Calculations of the Isothermal Flow in Axisymmetric Models of Combustor Geometries

Abstract

Measurements with laser-Doppler anemometry and calculations with finite-difference solutions of the time-averaged Navier-Stokes equations and a two-equation turbulence model, have been obtained for the turbulent isothermal flow in an axisymmetric geometry related to gas-turbine combustors. The results quantify the flow patterns in the arrangement and demonstrate the extent to which they can be represented by calculation. The discrepancies between measured and calculated results are shown to depend more on the distribution of grid nodes than on the turbulence model. Even with a distribution of nodes which is considered to be near optimum, differences between measurement and calculation exist and are particularly significant in the regions of steep velocity gradient immediately downstream of the incoming annular jet. The general trends are, however, correctly represented, and the calculation method has been used to determine the influence of the width of the annulus and of the jet gap. The results provide information of relevance to the development of calculation methods for real combustors, and this is discussed.