Partially premixed laminar gas flames from triangular burners

An experimental study of the effects of using triangular burner exit ports in place of the standard circular ports in a laminar partially premixed gas burner is presented, A natural gas burner employed in a small residential-scale heating system rated at 5.86 kW was modified. Air entrainment into the nonburning jets, emission indices of nitrogen oxides and carbon monoxide, and inflame temperature and composition profiles were measured. Flowfield in the near-nozzle region was visualized by shadowgraphy, Results show that triangular ports increase air entrainment by 30%, decrease nitrogen oxides emission by less than 15%, and increase carbon monoxide emission by 20%, The effects are explained in terms of the changes in now structure and instabilities caused by the noncircular geometry and sharp corners of the burner exit port.