Improving the biodiesel combustion and emission characteristics in the lean pre-vaporized premixed system using diethyl ether as a fuel additive

•Combustion characteristics of DEE, WCO biodiesel, and jet A-1 investigated in a LPP system.•DEE addition significantly improves combustion characteristics.•NOx, CO, and UHC levels reduced for W20D20 by 38.4%, 68%, and 69.6%, respectively. This paper is a lab-scale experimental study of the impact of employing diethyl ether (DEE) as an additive to waste cooking oil biodiesel with Jet A-1 on the combustion as well as emission features of a swirl-stabilized premixed flame. First, waste cooking oil biodiesel with a volume fraction of 20% was blended with Jet A-1 and symbolized as W20. Then, diethyl ether with a volume fraction of 20% was blended with 20% biodiesel and 60% Jet A-1, symbolized as W20D20. The three test fuels (W20, W20D20 blend, and pure Jet A-1) were premixed with preheated air and pre-vaporized before being admitted to the vertical cylindrical combustor having an inner diameter of 150 mm and a length of 500 mm via a swirl burner (radial type) of 0.55 swirl number and 8 straight vanes with an angle of 45°. Local flame temperatures and emissions were measured and recorded at 350 °C of preheated air with a constant equivalence ratio (φ) of 0.85. According to the findings, a relatively wide range of flame temperatures was observed in the flame of the W20 blend, while the W20D20 blend had a flame temperature distribution very close to that of the Jet A-1. The W20D20 blend reduced UHC emissions by 69.6%, CO emissions by 61.4%, and NOx emissions by 12.5% relative to Jet A-1 at the combustion chamber outlet. Overall, adding DEE to biodiesel significantly impacts both combustion and emission profiles.