Actively Controlled Afterburner for Compact Waste Incinerator

摘要

Active control of fluid dynamics has been used to enhance mixing in incinerator afterburner experiments and increase the DRE for a waste surrogate. Experiments were conducted in a 50 kW scale burner as well as 400 to 1200 kW burners which match the heat release rate of the proposed full scale afterburner for a compact shipboard methodology previously shown, in sub scale tests, to greatly increase DRE, reduce emissions, and allow much more compact incineration, has been proven to work at the full scale level. The open loop active control system is based on the concept of combustion in periodic axisymmetric vortices. Acoustic excitation was used to stabilize coherent vortices in the central air flow of a dump combustor like configuration. The fuel and waste are injected annularly at the dump. The pyrolysis surrogate is modulated indirectly by periodic entrainment created by roll-up of the main air vortex, as well as acoustic excitation of secondary air injection. The phase angle is controlled such that the combustibles are introduced into the air vortex at the right time during the vortex formation. This leads to good mixing, a controlled yet lifted partially premixed flame, high DRE and low pollutant emissions.