The increasingly stringent emission regulations and fuel consumption requirements have elevated the demands of internal combustion engines with higher fuel efficiency and lower emissions. It has been widely demonstrated that flash boiling spray can generate shorter and wider spray with improved atomization and evaporation to promote a better air-fuel mixing process. In this study, macroscopic (far-field) spray morphologies and primary breakup (near-field) characteristics of a two-hole gasoline direct injection injector are investigated under non-flash boiling and flash boiling conditions. High speed macroscopic and microscopic imaging was used to capture the overall spray structure and near-field characteristics, respectively. N-Hexane is used as the test fuel with the injection pressure ranging from 10 MPa up to 40 MPa. For sub-cooled liquid fuel sprays, increasing fuel pressure contributes to enhanced fuel atomization and evaporation. Evident collapses occurred under flare flash boiling conditions, and higher injection pressure weakened this phenomenon since the spray cone angle decreased due to a higher injection velocity.
王森，徐宏昌，李雪松，袁志远
. Characteristics of High-Pressure Spray of a Gasoline Direct Injection Injector Under Non-Flash Boiling and Flash Boiling Conditions[J]. Journal of Shanghai Jiaotong University(Science), 2024
, 29(2)
: 230
-236
.
DOI: 10.1007/s12204-022-2480-z
[1] ZHAO F, LAI M C, HARRINGTON D L. Automotive spark-ignited direct-injection gasoline engines [J]. Progress in Energy and Combustion Science, 1999, 25(5): 437-562.
[2] HOFFMANN G, BEFRUI B, BERNDORFER A, et al. Fuel system pressure increase for enhanced performance of GDi multi-hole injection systems [J]. SAE International Journal of Engines, 2014, 7(1): 519-527.
[3] PIOCK W F, BEFRUI B, BERNDORFER A, et al. Fuel pressure and charge motion effects on GDi engine particulate emissions [J]. SAE International Journal of Engines, 2015, 8(2): 464-473.
[4] HUSTED H, SPEGAR T D, SPAKOWSKI J. The effects of GDi fuel pressure on fuel economy [C]// SAE 2014 World Congress & Exhibition. Detroit, Michigan: SAE International, 2014: 2014-01-1438.
[5] YANG S Z, MA Z, LI X S, et al. A review on the experimental non-intrusive investigation of fuel injector phase changing flow [J]. Fuel, 2020, 259: 116188.
[6] LI X S, YANG S Z, LI T Y, et al. Investigations on near-field atomization of flash boiling sprays for gasoline direct injection related applications [J]. Fuel, 2019, 257: 116097.
[7] HWANG J, PARK Y, BAE C, et al. Fuel temperature influence on spray and combustion characteristics in a constant volume combustion chamber (CVCC) under simulated engine operating conditions [J]. Fuel, 2015, 160: 424-433.
[8] YANG S Z, LI X S, HUNG D L S, et al. In-nozzle flash boiling flow of multi-component fuel and its effect on near-nozzle spray [J]. Fuel, 2019, 252: 55-67.
[9] MOJTABI M, CHADWICK N, WIGLEY G, et al. The effect of flash boiling on breakup and atomisation in GDI sprays [C]//22nd European Conference on Liquid Atomization and Spray Systems. Como Lake: ILASS Europe, 2008: ILASS08-6-1.
[10] YANG S Z, LI X S, HUNG D L S, et al. Effect of injection pressure on nozzle internal flow and jet breakup under sub-cooled and flash boiling test conditions [J]. SAE Technical Paper, 2019: 2019-01-0286.
[11] XIAO D, QIU S Y, HUNG D, et al. Evaporation and condensation of flash boiling sprays impinging on a cold surface [J]. Fuel, 2021, 287: 119423.
[12] HE X, LI Y K, LIU C, et al. Characteristics of spray and wall wetting under flash-boiling and non-flashing conditions at varying ambient pressures [J]. Fuel, 2020, 264: 116683.
[13] CHAN Q N, BAO Y M, KOOK S. Effects of injection pressure on the structural transformation of flash-boiling sprays of gasoline and ethanol in a sparkignition direct-injection (SIDI) engine [J]. Fuel, 2014, 130: 228-240.
[14] PAYRI R, SALVADOR F J, MART′I-ALDARAV′I P, et al. ECN Spray G external spray visualization and spray collapse description through penetration and morphology analysis [J]. Applied Thermal Engineering, 2017, 112: 304-316.
[15] MONTANARO A, ALLOCCA L. Flash boiling evidences of a multi-hole GDI spray under engine conditions by Mie-scattering measurements [J]. SAE Technical Paper, 2015: 2015-01-1945.
[16] ZENG W, XU M, ZHANG M, et al. Macroscopic characteristics for direct-injection multi-hole sprays using dimensionless analysis [J]. Experimental Thermal and Fluid Science, 2012, 40: 81-92.
[17] ZHANG G M, HUNG D L S. Temporal investigations of transient fuel spray characteristics from a multi-hole injector using dimensionless analysis [J]. Experimental Thermal and Fluid Science, 2015, 66: 150-159.
[18] ZHANG M, XU M, HUNG D L S. Simultaneous twophase flow measurement of spray mixing process by means of high-speed two-color PIV [J]. Measurement Science and Technology, 2014, 25(9): 095204.
