Effect of Internal Flow Structure in Circular and Elliptical Nozzles on Spray Characteristics

Ku, Kun Woo; Hong, Jung Goo; Lee, Choong-Won

doi:10.1615/atomizspr.2012004192

Cited by 19 publications

(5 citation statements)

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“…In a twin-fluid spray nozzle, atomization is improved at a relatively lower pressure than that in a single spray nozzle. − However, compared to a single spray nozzle, in a twin-fluid nozzle, an assist gas is needed, more energy is consumed, and the shape of the nozzle is complex. In addition, it is difficult to find optimized conditions due to the relative lack of research and data on single spray nozzles, for which many experimental studies have been conducted, and twin-fluid spray nozzle characteristics. − …”

Section: Introductionmentioning

confidence: 99%

Effects of Y-Jet Nozzle Mixing Chamber Length and the GLR on Spatial Asymmetric Spray

2021

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The Y-jet nozzle is simpler to design than other twin-fluid nozzles and has various advantages such as having a wide turn-down ratio. For this reason, it is mainly used for industrial boilers and combustion. The Y-jet nozzle comprises liquid and assist gas supply ports, a mixing chamber, where two fluids (liquid and the assist gas) are mixed, and an exit orifice. The time it takes to mix the two fluids in the mixing chamber depends on the length of the chamber, which determines the spray and particulate properties. Therefore, the mixing chamber is one of the most important factors when designing the Y-jet nozzle. The gas to liquid mass flow rate ratio (GLR) is an important variable that affects the spray characteristics of the Y-jet nozzle. In this work, a laboratory-scale Y-jet nozzle spray experimental setup was developed to perform spray experiments. In particular, we observe the spray properties in the front and right directions to observe spatial spray properties. Significant results were obtained depending on the length of the mixing chamber, the spray pattern, and the Sauter mean diameter according to the GLR. We found that a mixing chamber with longer length reduces the effect of asymmetric spray and confirm that the central axis of spray is more stable.

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Section: Introductionmentioning

confidence: 99%

Effects of Y-Jet Nozzle Mixing Chamber Length and the GLR on Spatial Asymmetric Spray

2021

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“…By examining Table 2, we found the discharge coefficients of elliptical orifices (I3, I4) are larger than those of circular and square orifices, and the discharge coefficient becomes slightly higher with an increase of the axial ratio of the orifice (I3 > I4). However, Ku et al [16] reported that the volume flow rate of elliptical orifice is less than that of circular orifice, under the condition that the cross-sectional areas of all orifices were approximately the same. The reason of the contrary experimental observations between Ku et al and this work is complicated.…”

Section: A Spray Featuresmentioning

confidence: 99%

Effects of orifice geometry on spray characteristics of impinging jet injectors for gelled propellants

Yang

Zhuang

2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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1 This paper presents the results of an experimental study on breakup characteristics of gelled propellant liquid sheets formed by impinging jet injectors with different geometries of injector orifice (round, elliptic, and rectangular shape). Spray formation of gelled propellant from impinging jet injectors was described by carrying out experiments in a spray test facility. Considering the safety, a water based gel simulant was used instead of the gelled propellant in the experiments. The rheological characteristics of the gel simulant were tested. A high speed camera was used to grab the detailed information of the liquid sheet breakup process and spray development. The experiments were performed with injectors of different shape of injector orifice to test the geometrical effect of injector orifice on the spray characteristics. The experimental results showed that under the condition of identical sectional area, the shapes of liquid sheet formed by the impinging jet injectors with different shape of orifices were different. One special phenomenon is the thick liquid stream in the center of liquid sheet when the aspect ratio of rectangular orifice is great. The reason of this phenomenon is the axis-switching feature of the non-circular jets. The mass flow rates of square and elliptical orifices are larger than that of circular orifice. The flow rate of rectangular orifice becomes greater as the aspect ratio gets larger. The breakup length for injector with square orifice is shorter than that for injector with circular orifice. Although the elliptical jet behaves greater instability than circular jet, the liquid sheet breakup length of injector with elliptical orifice is not always shorter than that of injector with circular orifice. Generally, the breakup length of rectangular jet impinging injector increases with aspect ratio.

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“…Kasyap et al 15 studied the breakup behavior of liquid jet emanation of the elliptical orifice and circular orifice at the same outlet area, and found that the liquid jet from the elliptical orifice is more unstable than that from the circular orifice. Ku et al 16,17 studied the effect of the internal flow structure of circular and elliptical nozzles on liquid jet rupture under different injection pressures through numerical simulations and experiments, and found that the liquid jets emitted from elliptical nozzles become more unstable under the same jet pressure. With the increase of injection pressure, surface cracks were observed at the jet stream from the elliptical nozzle.…”

Section: Introductionmentioning

confidence: 99%

A new calculation formula to describe the dynamic pressure of water jet peening with elliptical nozzle for high-efficiency treatment

Zheng

Luo

Zhang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Water jet peening is a good potential method to control welding residual stresses. The water jet with elliptical nozzle can improve the treatment efficiency due to its large treatment area. In this article, the water jet velocity and dynamic pressure for different elliptical nozzle dimensions and standoff distances are discussed by numerical simulation. The results show that when the axial distance is 10 mm, the effective impact diameter of the elliptical nozzle a/b=8–12 is about 2 times or more than that of the circular nozzle. The length of the jet core of the elliptical nozzle is only related to the outlet structure and is independent of the inlet pressure. The correlation between the dimensionless core length of the elliptical water jet and its long and short axes is derived. When the ratio of the major axis to the minor axis is between 7 and 13, the core length of the elliptical water jet is 7–7.5 times that of its minor axis. Combining the suitable treatment area and dynamic pressure, the elliptical nozzle with an axis ratio of 8 is recommended to control the welding residual stress. Finally, a new formula for calculating dynamic pressure distribution is proposed for the elliptical nozzle water jet at different stages.

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Effect of Internal Flow Structure in Circular and Elliptical Nozzles on Spray Characteristics

Cited by 19 publications

References 0 publications

Effects of Y-Jet Nozzle Mixing Chamber Length and the GLR on Spatial Asymmetric Spray

Effects of Y-Jet Nozzle Mixing Chamber Length and the GLR on Spatial Asymmetric Spray

Effects of orifice geometry on spray characteristics of impinging jet injectors for gelled propellants

A new calculation formula to describe the dynamic pressure of water jet peening with elliptical nozzle for high-efficiency treatment

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