Spray dynamics of synthetic dimethyl carbonate and its blends with gasoline

• Published in: Fuel (Guildford) 2023-06, Vol.341, p.127696, Article 127696
• Main Authors: Huang, Weidi, Hendra Pratama, Raditya, Oguma, Mitsuharu, Kinoshita, Koichi, Takeda, Yoshinaka, Suzuki, Shunsuke
• Format: Article
• Language: English
• Subjects: dimethyl carbonate (DMC); Evaporating conditions; Spray dynamics; Synthetic fuels; X-ray phase-contrast imaging
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.127696

•Spray dynamics of synthetic DMC and its blends with gasoline is investigated.•Fuel properties of synthetic DMC and its blends with gasoline are quantified under varied conditions.•DMC content enlarges the spray spreading angle and minimums the near-nozzle spray velocity.•DMC has similar SMD and droplet number with gasoline under evaporating conditions.•Existing empirical correlations are feasible to predict the spray characteristics of the DMC-gasoline blends. Synthetic dimethyl carbonate (DMC) is a promising alternative or oxygenated additive fuel to reduce not only CO2 but also particle number (PN) emissions from gasoline direct injection (GDI) engines. Despite many investigations on the engine performance of DMC-gasoline blends in the literature, limited reports can be found focusing on their spray characteristics. However, a comprehensive understanding of spray characteristics is crucial to interpret the results of GDI engine tests. Therefore, this study was to examine the near-nozzle spray dynamics of the DMC-gasoline blends by using the X-ray phase contrast imaging technique. First, the fuel properties of the synthetic DMC and regular gasoline blends were quantified. Then, the near-nozzle spray dynamics were examined in both non-evaporating and evaporating conditions, and discussions were made accordingly to link the near-nozzle spray dynamics with fuel properties. It is found that increasing DMC content could enlarge the spray spreading angle and reduce the near-nozzle spray velocity by up to +22 % and –18 %, respectively. The near-nozzle-exit spray velocity depends sharply on the fuel density as the DMC content varies in the blends. However, this dependency gradually becomes insignificant as the spray propagating distance increases. Pure DMC has the largest Sauter mean diameter (SMD) and least droplet number than other blends, but they tend to be consistent as the ambient gas temperature increases. The existing empirical correlation is still feasible to predict the SMD of the DMC-gasoline blends, but certain tuning of the constants is necessary. Within the experimental conditions in this study, the DMC-gasoline blends should undergo the same spray breakup regime, i.e., the atomization regime.