Feasibility study of the diluted combustion in a semi-industrial domestic heating boiler at low temperatures

The aim of this work is to assess the technical feasibility and highlight the specific problem of application of diluted (or mild) combustion in a medium scale boiler by direct gas injection. The main difficulty is due to the high geometrical confinement and heat losses of a typical boiler combustion chamber, which prevents from getting the minimum level of reactants dilution and temperature needed to reach mild combustion regime. In this work, a preliminary CFD study has been performed to select a jet burner and secondary gas injector able to generate sufficient dilution and temperature of the air and gas jets before they meet in the combustion chamber of the boiler.