A study on NO formation in propane-air diffusion flame has been undertaken. The effects of $CO_2$ addition on NO formation have been investigated. $CO_2$ was added as a percentage of total oxidizer supply from air-side. NO, temperature, total and radiative incident heat fluxes has been measured experimentally in a steady state. Photographs of flame are taken to observe flame structure.
Addition of $CO_2$ reduces NO formation through prompt NO mechanism and also reduces radiative heat flux due to absorbing radiation inside the flame. Effect on temperature is found increasing at all axial locations of flame due to increase in swirl, change in flame shape and structure.