Experiment and analysis on the spray characteristics of diesel/polyoxymethylene dimethyl ethers (PODE)/ethanol blends in non-reacting environment

Polyoxymethylene dimethyl ethers (PODE) and ethanol are both potential alternative fuels, and PODE can be used as a cosolvent for diesel/ethanol blends. The spray and fuel-air mixing characteristics of D100 (neat diesel), DP20 (80 %vol. diesel and 20 %vol. PODE), DPE15 (85 %vol. DP20 and 15 %vol. ethanol) under various injection and ambient pressures were studied in a constant volume combustion chamber. The results show the spray tip penetration of the three fuels are not significantly different and DPE15 is slightly lower than the other two fuels. Adding PODE and ethanol to diesel can increase the spray cone angle and improve the radial dispersion. In addition, there is no significant difference in the spray projected area of the three fuels. Desantes model with fitted parameters and Naber model had good prediction accuracy for spray tip penetration under all experimental conditions. The equivalence ratio of DP20 is obviously lower than that of diesel, and the addition of ethanol to DP20 lead to a further decrease of the equivalence ratio. The present measurements fill the gap in the research on the spray characteristics of diesel/PODE/ethanol blends, and provide benchmark for validation of the high-fidelity numerical simulation of the blends spray.

Automated summary

The addition of PODE and ethanol to diesel can improve spray characteristics, including increasing the spray cone angle and improving radial dispersion. The Desantes model and Naber model demonstrate good prediction accuracy for spray tip penetration under different experimental conditions. DP20 has a significantly lower equivalence ratio than diesel, and adding ethanol to DP20 further decreases the equivalence ratio.