Effect of diethyl ether addition to waste cooking oil biodiesel on the combustion and emission characteristics of a swirl-stabilized premixed flame

[Display omitted] •Combustion characteristics of DEE/waste cooking oil biodiesel/Jet A-1 blends investigated in a swirl-stabilized lean prevaporized premixed combustor.•Diethyl ether addition enhanced the viscosity, surface tension, and sauter mean diameter of biodiesel.•Diethyl ether blends shared a similar temperature distribution to Jet A-1.•The lowest Nitrogen oxides and carbon monoxide emissions were recorded for the B20D30 blend.•The lowest unburned hydrocarbon emissions were recorded for the B20D10 blend. Waste cooking oil biodiesel is a promising alternative to diesel and jet fuels. However, the challenge of using waste cooking oil biodiesel is its higher viscosity and lower volatility than diesel fuel, which hinder its spray and atomization from achieving diesel levels. These drawbacks can be enhanced by adding a less viscous fuel like diethyl ether. Thus, an experimental approach has been performed to investigate the effect of diethyl ether addition to waste cooking oil biodiesel in the lean pre-vaporized premixed system. Test fuels considered in this study are B20 (20% biodiesel + 80% Jet A-1), B20D10 (20% biodiesel + 10% diethyl ether + 70% Jet A-1), B20D30 (20% biodiesel + 30% diethyl ether + 50% Jet A-1) as well as pure Jet A-1. These blends are applied in the lean pre-vaporized premixed system with preheated air at 350 ℃ at a fixed equivalence ratio of 0.85 (lean condition). Results showed a 68, 38.4, 14.5, and 43.4% decrease in CO, NOx, CO2, and UHC emissions, respectively, for the B20D30 blend, compared with pure Jet A-1 fuel at the combustor exit, while the B20D10 blend indicated a 15.8, 8.9, 6.17, and 51.4% drop in CO, NOx, CO2, and UHC levels, correspondingly. Jet A-1 achieved a higher maximum temperature than those for other blends. The B20 blend revealed a relative variation in flame temperature distribution, while diethyl ether blends shared a similar temperature distribution compared with Jet A-1. Generally, B20D10 and B20D30 blends had the ability to reduce emission levels. Overall, it can be concluded that the recommended diethyl ether blending ratio is 30%, regarding emission levels and flame temperature profile.