Journal of Jilin University(Engineering and Technology Edition) ›› 2024, Vol. 54 ›› Issue (6): 1512-1518.doi: 10.13229/j.cnki.jdxbgxb.20220960

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Effect of fuel flow in self-excited oscillating nozzle on near-nozzle region jet atomization

Yong-qiang GAO(),Shi-qian ZHOU,Long QI,Qian-qi YIN,Xue-tao HUANG,Jia-xing ZHANG   

  1. School of Automotive Engineering，Shandong Jiaotong University，Jinan 250357，China
  • Received:2022-07-31 Online:2024-06-01 Published:2024-07-23

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Abstract:

In order to further understand the mechanism of breakup of diesel jet， a mathematical model of fuel flow in self-excited oscillating nozzle was built based on large eddy simulation（LES） and Volume of Fluid （VOF） model. The results show that fluid vorticity and disturbance intensity in the self-excited oscillating nozzle is significantly increased， and it can increased by more than three times. The disturbance intensity is more sensitive to jet breakup in the near-nozzle region， which can significantly improve the jet breakup effect. The jet breakup length（SL） is greatly reduced， which can varies from 2 to 5 times of the outlet diameter at near-nozzle region. At the same time， the spray cone angle in the near-nozzle area is also increased， which can increase by more than 60%. The fuel jet atomization effect is greatly improved in the self-excited oscillating nozzle. The numerical simulation results is also provided a strong theoretical basis for the self-oscillating pulsed atomizing nozzle.

Key words: energy and power engineering, self-excited oscillating nozzle, atomization characteristic, breakup mechanism of jet, turbulence perturbation

CLC Number: 

  • TK427

Fig.1

Physical model of self-excited oscillating nozzle"

Table 1

Simulation parameters"

参数数值参数数值
喷射压力Pin/MPa100入口直径d1/mm0.16
背压Pout/MPa0.1出口直径d2/mm0.2
柴油密度ρl /（kg·m-3）840振荡腔直径D（2~6）d2
气体密度ρv /（kg·m-3）20撞壁夹角α/（°）120
表面张力/（N·m-1）0.026振荡腔长度L（1~3）d2

Fig.2

Verification of grid independence"

Fig.3

Comparison of numerical calculation and experiment results"

Fig.4

Distribution of vorticity contour in self-excited oscillation nozzle"

Fig.5

Distribution of vorticity contour in traditional circular nozzle"

Fig.6

Pressure standard deviation and disturbance intensity of nozzle outlet"

Fig.7

Distribution vorticity， kinetic energy and velocity in the near nozzle"

Fig.8

Isosurface of 0.2 fuel volume fraction at 20 μs"

Fig.9

Isosurface of 0.2 liquid volume fraction at different times"

Fig.10

Comparison of spray cone angle between self-excited oscillation and circular nozzle"

Fig.11

Jet structure of different nozzles in the near field"

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