Experimental and Numerical Investigation of LPG-Fueled Inverse Diffusion Flame in a Coaxial Burner

Abstract

An experimental and numerical investigation of unconfined liquefied petroleum gas (LPG) fuelled inverse diffusion flame (IDF) is presented. The effect of air-fuel velocity ratio on the appearance of the LPG IDF are investigated. A fixed air jet velocity of Va = 11.31 m/s is chosen for the analysis, while the fuel jet velocity is varied from 0.014 m/s to 0.083 m/s. The observations indicate that the air-fuel jet velocity ratio has significant effect on the flame appearance of LPG IDF. It is found that the flame length increases with increase in fuel jet flow. Actual flame in burner is highly complex in nature as it involves momentum, mass and energy transfer in highly turbulent flow regime. To extract detailed information of flow physics, numerical analysis of LPG IDF is performed. It is observed that temperature along the centerline of IDF increases as distance from burner exit (Z) increases. This nature of temperature distribution indicates that the central cold air in the air jet is gradually heated toward the downstream of the IDF. The highest flame temperature is noticed at Z = 30 mm. The highest flame temperature predicted numerically at axial height of 30 mm is central portion of the blue zone of the flame which is main reaction zone.