Research and Development to Improve Naval Shipboard Waste Management Using Compact, Closed-Loop Controlled Waste Incinerator

摘要

The US Navy commitment to environmentally clean ships require that the present practices of waste storage and off loading and overboard discharge be eliminated. Thermal waste treatment onboard Naval vessels is preferred as it accomplishes many waste processing goals including volume reduction, sterilization and detoxification. It is also cost-effective and among the safest approaches requiring little specialized personnel training. Unfortunately existing seaworthy incinerator designs that meet the Navy's size and weight limitations are not expected to meet the International Maritime Organization (IMO) standards when operating under the higher throughput demands of future target shipboard operations. This has led to the exploration of novel approaches, such as the use of forced acoustics, in order to maintain compact incineration systems capable of increased waste throughput. Energy and Environmental Research Corporation (EER) and the Naval Air Warfare Center Weapons Division (NAWCWD) have developed a forced acoustic afterburner that improves heat transfer, turbulent mixing and firing density. The afterburner designed incorporates a central air jet issuing past a dump plane. The forcing frequency of the air jet is controlled to match the jet's natural frequency causing formation of coherent vortices in the afterburner chamber, as illustrated in Figure 1. Air-starved reaction products enter circumferencially around the air jet and are entrained into the shedding vortices, mixing the reaction products with the air through strain-enhanced diffusion and convection. Ignition of the gases is strain-delayed allowing enhanced mixing, lower peak flame temperatures and the elimination of cold fuel pockets. This combustion mechanism reduces products of incomplete combustion and lowers formation of oxides of nitrogen (NOx).