An experimental study of NOx emissions from a Helmholtz resonator

Abstract

A detailed experimental investigation of NOx emissions was conducted in order to get more precise combustion data for a Helmholtz resonator valveless pulse combustor. A laboratory-scale model of the combustor was designed and operated with a non-premixed input of air and propane. The effects of fuel flow rate, temperature, and pressure amplitude on NOx emissions through a variety of experimental tests were studied. The tests were carried out for three tailpipe lengths, two inlet pipe lengths, and two combustion chamber volumes. The results revealed that the variations in operational and design parameters have a significant impact on NOx emissions. NOx emissions reach a maximum value near the stoichiometric condition as temperature and pressure, which are related to the fuel flow rate, reach their maximum values. Experiments show inverse relationships between CO and NOx emissions. Furthermore, the findings show that NOx reduction increases with increasing tailpipe and inlet pipe lengths, as well as small volume combustion chambers.