International Conference on Advanced Automotive Technology (ICAT) 2018
July5-7, 2018, Gwangju, Korea
TITLE, TITLE, TITLE (Arial 18pt)
Author (Arial 12 pt)1, Author2,and Author1,*
1School of Mechanical Engineering, ChonnamNational University
2Korea Automotive Technology Institute
Corresponding author: Gil Dong Hong, Email:
Keywords: Keyword (Times new roman, 10pt) (*5 ~ 6 words)
1. Introduction
In order to improve the atomization characteristics with respect to the nozzles, there have been reported results of studying the shape of the exit orifices of the nozzles instead of the circular nozzles by using ellipses or triangles [1,2]. However, it isthe present state that the research on the nozzle having a non-circular orifice is relatively inferior to that of the circular nozzle. Therefore, there is not enough data on spray
2. Research Method and Procedure
be confirmed in real time by the sensor of the data acquisition board(NI
Fig. 1. Schematic diagram of the experimental setup for measurement of spray characteristics
DAQ-9172, National instruments). The internal pressure of the nozzle was measured by a pressure transducer and confirmed in real time, like the flow rate, using a data acquisition board. The flow rate and the internal pressure of the nozzle were used as the values obtained by averaging the values of flow rate sensor and pressure sensor sampled at 100Hz for 5 seconds. Using the Schlieren method expressing the change of the refractive index of light as the contrast between light and shade, it was performed that image shooting of spraying for visualization of injected fluid. The SMD of the fluid injected from the nozzle was measured, using laser diffraction method, at the downstream of the spray below 200mm from nozzle tip, by a laser in the spray tip direction and a detector receiving it. The nozzle used in the experiment is an Effervescent type nozzle made of transparent acrylic which can observe the inside of the nozzle. Two types of nozzles were manufactured, one circular nozzle with an outlet orifice diameter of 3 mm and an elliptical nozzle with an outlet area similar to a circular nozzle. An elliptical nozzle is an E1 nozzle with a 2:1 ratio of major axis to minor axis and an E2 nozzle with a ratio of major axis to minor axis of 3:1. On the other hand, we used aerorators classified into 1.2, 1.7, and 2.1mm according to the diameter of the hole. The ratio of the total area of the aerorator to the area of the exit orifice is expressed as area ratio, the three kinds of nozzles have about 2, 4, and 6 area ratios.
3. Results and Discussion
In Fig. 3. graphs show a tendency that the discharge coefficient decreases with increasing ALR. This was the same regardless of the shape of the nozzle exit orifice. However, the discharge coefficient proposed by Jedelsky was found to be about 3 ~ 4 times larger than the pressure spray method. Effervescentnozzle used in this experiment is a type of twin-fluid nozzle, theinfluence of the assist air is considered to beimportant.
Fig. 2. Average internal pressure differences in nozzle shape (aerorator 1.2mm)
4. Conclusion
1.The average internal pressure of the nozzle according to ALR was about 12.3% higher than that of C nozzle. In addition, it was confirmed that the difference in the internal pressure of the nozzle according to the area of the aerators was not large regardless of the nozzles. Therefore, the pressure inside the nozzle is more influenced by the exit orifice shape than the total area of the aerator.
Acknowledgments
This work was supported by the Doosan Heavy Industries & Construction grant funded by the Doosan Heavy Industry & Construction(No. 201712590000)
5. Reference
- LeeC.W., LeeY. J., ParkJ. W., and TerasimaK., “Effect of nozzle hole configuration on spray characteristics for diesel engine”, 10th Annual Conf. on Liquid Atomization and Sprat Systems, Seoul, Korea, pp. 267~272, 2005