Investigation of isothermal convective heat transfer in an optical combustor with a low-emissions swirl fuel nozzle

Abstract

Modern combustor design optimization is contingent on the accurate characterization of the combustor flame side heat loads. The present work focuses on the experimental measurement of the isothermal (non-reacting) convective heat transfer along a fused silica optical can combustor liner for Reynolds numbers ranging between 11 500 and 138 000. The model combustor was equipped with the SoLoNOx swirl fuel nozzle from Solar Turbines Incorporated, subjecting the liner walls to realistic isothermal flow and turbulence fields. Infrared (IR) imaging through fused silica was demonstrated, and a novel estimation of the three-dimensional conduction heat losses for steady state constant heat flux experiments was developed. A maximum heat transfer augmentation of ~18 was observed with respect to fully developed turbulent pipe flow correlations. Contrary to other investigations, the augmentation magnitude and distribution are shown to be approximately constant with Reynolds number (particularly away from the impingement location). Particle Image Velocimetry (PIV) was included to support the heat transfer measurements, suggesting that peak heat transfer occurred 0.12 nozzle diameters upstream of the jet reattachment point along the liner. Reynolds-Averaged Navier Stokes (RANS) computations are shown to yield peak heat transfer predictions within 17.4% of the experimental results when using the realizable k-ε turbulence model and enhanced wall treatment. The measurements were further analyzed in the context of results from other heat transfer studies on gas turbine combustors.

A New Test Facility for Investigating Thermal Behaviour of Effusion Cooling Test Plates for RQL Combustors

“…Starting from these constraints, and having in mind the necessity of replicating a representative swirling flow the test rig has been designed to work at engine swirl Reynolds number. The Reynolds similitude is not a mandatory conditions for overall effectiveness distribution tests, nevertheless it should be respected especially for combustion chamber working at moderate Reynolds value in order to correctly replicate the development of main flow in the chamber and, in some cases, the swirler behaviour (Gomez-Ramirez et al [11]). As a consequence of imposing a Re sw value, the swirler behaviour can be controlled by increasing the pressure of the rig in order to replicate or limit the chamber pressure drop to typical engine values.…”

“…PIV and IR termography caractherization of an engine scale single-can combustors was recently conducted at Virginia Tech Advanced Power and Propulsion Laboratory [11,12]. These investigations have addressed the impact of important combustor parameters on the reacting fluid dynamics.…”