Executive Summary : | Enhancement of thermal efficiency with reduced emissions remains the most challenging task in combustion research. Many novel methods have been developed in this direction. Although much of the investigations have been done in the combustion field, still there are several challenges that are required to be solved. Because of its inter-disciplinary nature, the complete science (especially the chemical kinetics part) of every problem is not so clear. One of the most important problems is the adverse effect of the combustion emissions on the environment like CO, NOx, Soot, particulates, etc. Combustion with emulsion fuel, plasma assisted combustion and MILD combustion are most recent techniques among them. Emulsion fuel can be fuel-in-water or water-in-fuel types. Emulsion fuels have shown tremendous capability in improving efficiency of fuels and also in reduction of fuel cost. It also reduces the CO2, SOx and NOx emissions. However, avoiding sedimentation for a longer duration in emission fuels is a difficult task and therefore limits its use in the combustors of engines running for a long time. Experimental and numerical studies on MILD combustion have shown that the thermal efficiency is increased due to heat recirculation and emissions are reduced due to decreased temperature of the flame by reactants dilution. The MILD combustion is well studied at ambient pressure. However, stabilization of MILD combustion at high pressure is big challenging issue and ongoing research.
Addition of diluents is another method of controlling emissions. Steam, nitrogen, Argon and carbon dioxide are some of the common diluents incorporated by researchers. Since steam has superior thermal and chemical properties than other diluents, it is selected as the diluent in the present investigation. Also steam is easily available and also inexpensive. In this project, high pressure steam diluted novel combustor will be developed to achieve low emissions. The preliminary computational studies help in achieving the suitable recirculation and optimal range of dilution. Subsequently the combustor will be fabricated and experiments will be conducted to fulfill the objectives of the proposal. The operating pressure of the combustor will be varied up to 20 bar. Effect of high pressure and steam dilution on chemical kinetics, reaction distribution and emissions will be studied. Very little research is done using both swirl flow and steam dilution in a combustor operates at high pressure. Hence, this proposal is aimed to analyze combustion characteristics at high pressure and the oxidizer is diluted with steam. Sole aim of the present proposal is to reduce the emissions from the combustor to ultra low level. The successful development of the proposed combustor operates at high pressure (20 bar) will help in controlling NOx and CO emissions which are the primary pollutants. |