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

•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.