Monitoring the Combustion Characteristic of Premixed Burners with Flame Ionization Current

Abstract

Fully premixed burners are widely used in the field of gas boilers, and the excess air rate is a crucial parameter to control. In this paper, a low-cost solution for monitoring the excess air rate based on the flame ionization current is applied to premixed burners. The ion signal measurement system is independently developed by the authors’ research group to convert a weak ion signal into a measurable detection voltage. The detection voltage of the metal fiber (MF) and stainless steel (SS) are compared. When the excess air rate is in the range of 1.1–1.5, the detection voltage of the MF and SS burner decreases from 1.914 to 1.217 V and 1.342 V to 0.693 V. Moreover, the function is established because both of them have a strong linear relationship. Based on Class 5 of NOx emissions (with a minimum value of 40 ppm) with respect to the European norm (EN 677), the detection voltage of the MF and SS burner is lower than 1.810 and 1.216 V, as the heat load is 24 kW, respectively.