Participants
Bok Jik Lee
Motivation and Objectives
Combustion-based
power generators in small dimensions have advantages over batteries in favor of
their high power density. One of the main challenges is the difficulty in flame
stabilization in the combustor with a high surface-to-volume ratio. Bluff-body
flame holder is one approach to promote combustion stability. In this project,
high fidelity simulations are conducted in order to understand the fundamental
mechanisms of flame stabilization and blow-off behind a bluff body. Advanced
analytical diagnostic tools are utilized to identify and characterize the blow-off
and re-attachment processes.
Approach
Direct
numerical simulations solve fully compressible multi-species reactive
Navier-Stokes equations with high order explicit discretization in space and explicit
integration in time, with detailed chemical kinetics. Robust non-reflecting Navier-Stokes
characteristic boundary conditions are employed for both inflow
and outflow boundaries. A square-shape bluff-body is computationally
represented by a set of logical sub-blocks.
Highlights of Results
At near-blowoff
inflow velocity, periodic local extinction and recovery of flame is observed.
Local extinction occurs near the downstream end of the recirculation area behind the bluff-body.
