Velocity Field Measurements in a Non-Premixed, Bluff-Body Burner using Digital Particle Image Velocimetry

摘要

The non-premixed, bluff-body burner provides both an industrially significant flow configuration and an academically useful tool for the development and validation of predictive CFD models. The bluff-body configuration is used to provide flame stabilisation in burners ranging from a few kW to several MW. The unsteady nature of the flame/flow interaction in the recirculating flow of a bluff-body wake provides a challenging scenario for CFD. Previous studies of bluff-body stabilised flows have provided detailed measurements of velocity fields for unconfined flames only. The aim of the current work is to provide detailed data of the velocity field in a laboratory scale, confined, non-premixed bluff-body burner with a blockage ratio of 0.44. The fuel and air streams were introduced into a circular combustion chamber of 84.5mm internal diameter manufactured from transparent Suprasil to allow the application of laser-based optical diagnostics. Data is presented for the velocity field for reacting flow measured using digital particle image velocimetry (DPIV) consisting of 2-D maps of time-averaged velocity and turbulence fields together with derived profiles of turbulence energy and shear stress. The prevailing fuel and air flow rates gave rise to a flow pattern that was dominated by three toroidal recirculation zones. The influence of these recirculation zones on the flow behaviour is investigated.