Investigation of Non-premixed LPG Combustion Characteristics on a Porous Bluff Body Slot Burner

This study aims to examine the characteristics of synthetic liquefied petroleum gas (LPG) flames by varying a bluff body shape and including a porous material (nickel foam) into a non-premixed slot burner configuration. The primary objective of this investigation was to examine the impact of different airflow bluff body shapes (specifically cylindrical, spiral, droplet, and cylindrical with holes) on various flame characteristics, including flame temperature, CO and NO_x emissions, and flammability limit. The study aimed to assess these effects under varying conditions, including equivalence ratios ranging from 0.25 to 2.00 and firing rates from 0.53 to 4.27 kW. The goal of this research was to develop methods to enhance the combustion of liquefied petroleum gas (LPG) for industrial applications. The study found that the combustion characteristics of the porous-bluff body slot burner (PBSB) had an impact on the flame structure and led to an increased length of the premixed flame. The maximum soot-free length fraction (SFLF) was observed at flame temperatures ranging from 769.00 to 1180.00 °C. The study revealed that the recorded CO emissions ranged from 37.11 to 133.80 ppm, while NO_x emissions ranged from 0.00 to 67.40 ppm. Furthermore, enhancement of the recirculation zone resulted in a greater blow-off limit for bluff bodies of various shapes. Specifically, the blow-off limits were improved at equivalence ratios of 0.040, 0.068, 0.073, and 0.075 for spiral, droplet, cylindrical with holes, and cylindrical shapes, respectively. The findings of the current study indicate that a porous-bluff body slot burner (PBSB) potentially improves the LPG combustion characteristics with safety.