The fuel flow pattern in the fuel injection nozzle of diesel engine is a complex and changeable phenomenon, which is easily affected by various factors, bringing the differences of flow patterns between multiple injection cycles. To solve the above problem, a visual experimental platform of fuel injection nozzle was built, in which the 100 injection cycles of diesel engine on the same working condition were photographed via shadowgraphy to study the difference in fuel flow pattern in the nozzle by ensemble average processing method. The cyclic variation rate K of fuel flow pattern is defined. Results demonstrate that the fuel flow pattern tends to be the same in multiple fuel injection cycles, but there is a strong randomness at the starting of injection and after ending of injection; the K can be reduced by decreasing the injection pressure and the inclination angle of orifice, so that the fuel flow pattern in the nozzle tends to be consistent.
HayashiTSuzukiMIkemotoM. Effects of internal flow in a diesel nozzle on spray combustion. Int J Eng Res2013; 14: 646–654.
2.
WeiMGaoYYanF,et al.Experimental study of cavitation formation and primary breakup for a biodiesel surrogate fuel (methyl butanoate) using transparent nozzle. Fuel2017; 203: 690–699.
3.
YinBYuSJiaH,et al.Numerical research of diesel spray and atomization coupled cavitation by large eddy simulation (LES) under high injection pressure. Int J Heat Fluid Flow2016; 59: 1–9.
4.
DukeDSwantekATiloccoZ, et al.X-ray imaging of cavitation in diesel injectors. SAE Int J Eng2014; 7: 1003–1016.
5.
MitroglouNMcLornMGavaisesM,et al.Instantaneous and ensemble average cavitation structures in diesel micro-channel flow orifices. Fuel2014; 116: 736–742.
6.
TakenakaNKadowakiTKawabataY,et al.Visualization of cavitation phenomena in a diesel engine fuel injection nozzle by neutron radiography. Nucl Instrum Methods Phys Res Sect A2005; 542: 129–133.
7.
MitroglouNLorenziMSantiniM,et al.Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows. Exp Fluids2016; 57: 175–189.
8.
MoonSGaoYParkS,et al.Effect of the number and position of nozzle holes on in- and near-nozzle dynamic characteristics of diesel injection. Fuel2015; 150: 112–122.
9.
PrasetyaRSouAMoonS,et al.X-ray phase contrast imaging of cavitation and discharged liquid jet in nozzles with various sizes. At Sprays2019; 29: 59–78.
10.
DukeDJMatusikKEKastengrenAL,et al.X-ray radiography of cavitation in a beryllium alloy nozzle. Int J Eng Res2017; 18: 39–50.
11.
GhijiMGoldsworthyLBrandnerPA,et al.Analysis of diesel spray dynamics using a compressible Eulerian/VOF/LES model and microscopic shadowgraphy. Fuel2017; 188: 352–366.
12.
ShibataSNishioSSouA,et al.Evaluation of cavitation in injector nozzle and correlation with liquid atomization. J Vis2015; 18: 481–492.
13.
TaoQSongXLeiY,et al.Influence of inlet pressure on cavitation flow in diesel nozzle. Appl Therm Eng2016; 109: 364–372.
14.
Gomez SantosEShiJGavaisesM,et al.Investigation of cavitation and air entrainment during pilot injection in real-size multi-hole diesel nozzles. Fuel2020; 263: 116746.
15.
TaskiranOO. Investigation of the effect of nozzle inlet rounding on diesel spray formation and combustion. Fuel2018; 217: 193–201.
16.
WenHJiangYMaJ. Effect of fuel mass flow at the end of injection on cavitation and gas ingestion in the nozzle. Appl Sci2021; 11: 258.
17.
GaoYWeiMYanF,et al.Effects of cavitation flow and stagnant bubbles on the initial temporal evolution of diesel spray. Exp Therm Fluid Sci2017; 87: 69–79.
18.
KubotaAKatoHYamaguchiH. A new modelling of cavitating flows: a numerical study of unsteady cavitation on a hydrofoil section. J Fluid Mech1992; 240: 59.
19.
JiangGZhangYWenH,et al.Study of the generated density of cavitation inside diesel nozzle using different fuels and nozzles. Energy Convers Manage2015; 103: 208–217.
20.
QiuTSongXLeiY,et al.Effect of back pressure on nozzle inner flow in fuel injector. Fuel2016; 173: 79–89.
21.
ZhangXHeZWangQ,et al.Effect of fuel temperature on cavitation flow inside vertical multi-hole nozzles and spray characteristics with different nozzle geometries. Exp Therm Fluid Sci2018; 91: 374–387.
22.
ChenZHeZShangW,et al.Experimental study on the effect of nozzle geometry on string cavitation in real-size optical diesel nozzles and spray characteristics. Fuel2018; 232: 562–571.
23.
MitroglouNGavaisesM. Mapping of cavitating flow regimes in injectors for medium-/heavy-duty diesel engines. Int J Eng Res2013; 14: 590–605.
24.
MaJWenHJiangS,et al.Formation and development of cavitation in a transparent nozzle with double orifices on different planes. Energ Source Part A. Recov Utiliz Environ Effects2019; 41: 1–15.
25.
DaiYCDaiCY. Prediction for the cetane number of diesel fuels from refractive Index. Chem Eng Oil Gas2000; 1: 23–25, 1–0.
26.
GuoGHeZZhangZ,et al.Visual experimental investigations of string cavitation and residual bubbles in the diesel nozzle and effects on initial spray structures. Int J Eng Res2020; 21: 437–447.
27.
WangZDaiXLiuF,et al.Microscopic study on the mechanisms for formation of the initial spray morphology. Fuel2019; 235: 715–722.
28.
SouAHosokawaSTomiyamaA. Effects of cavitation in a nozzle on liquid jet atomization. Int J Heat Mass Transfer2007; 50: 3575–3582.
29.
ChenZHeZXGuoGM,et al.Visual experiment of the effects of string cavitation and stagnant bubbles on spray characteristics in tapered diesel nozzle. J Eng Thermophys2019; 40: 953–959.
30.
ZhangZYHeZXGuoGM,et al.Experiment of transient cavitating flow in the real-size diesel injector nozzle. Trans CSICE2017; 35: 136–141.
31.
HeZXZhongWJHuangYL,et al.Investigation of transient behavior of cavitation flow in injector nozzles affected by the needle movement. Trans CSICE2012; 30: 336–342.
