• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.1005-1012
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• 2011

The purpose of this study was to investigate the internal nozzle flow and cavitation characteristics numerically in both circular and elliptical nozzles. The program FLUENT 6.2 was used to perform the numerical simulation of the cavitating flow in the nozzles. A comparison was made between the cavitation shapes predicted numerically and those found experimentally in order to validate the numerical solution. This study showed that the cavitation in the circular nozzle had a cylindrical shape that was symmetrical with the nozzle axis. However, the cavitation in the elliptical nozzles had a horseshoe-like shape. In addition, the radial velocity distribution varied between the major and the minor axis planes when the working fluid was flowing into the inlet.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.320-324
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• 2017

Effect of elliptical orifice on the spray characteristics of liquid jet ejecting into subsonic crossflows were experimentally studied. Circular/elliptical plain-orifice injectors, which had different ratios of the orifice length to diameter and major axis to minor axis, were used for transverse injection. Compared with the previous research, breakup lengths of elliptical nozzles are shorter than circular nozzles at all experimental condition. Cavitation/hydraulic flip are considered as a reduction in the breakup length at all circular/elliptical nozzle. In the case of liquid column trajectories, major axis which was placed to the crossflows, increases the frontal area of the liquid column exposed to the crossflows. Hence, the aerodynamic force exerted on the jet is increased and the penetration depth is reduced.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.19-28
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• 2017

Effects of cavitation and hydraulic flip in circular and elliptical nozzles on the flow characteristics have been studied. Spray tests were conducted using injectors with different ratios of an orifice length(L) to a diameter(d) and of a major axis diameter(a) to a minor axis diameter(b). With the increment of an injection pressure drop, discharge coefficients slightly decreased in cavitation flows, and those suddenly dropped and were almost constant in hydraulic flip flows. For elliptical nozzles with L/b > 8 and L/a < 8, discharge coefficients and flow patterns showed different results from those in previous circular nozzles. When a flow in the elliptical nozzle was under steady condition, as the liquid column went downstream from the nozzle, its spray angle a little decreased in the plane of a major axis and increased in the plane of a minor axis.

• Journal of ILASS-Korea
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• v.26 no.1
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• pp.33-39
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• 2021

Y-jet nozzle has a wide fuel flow rate range and turn-down ratio, thus, it is used in industrial boilers, furnace and agricultural atomizer. However, it has asymmetrical spray characteristics due to the nozzle design factors. Therefore, in this study, asymmetric spraying characteristics of the elliptical Y-jet nozzle was studied by using the lab-scale spray apparatus. As a result, the elliptical Y-jet nozzle had lower gas mass flow rate than circular Y-jet nozzle at same gas pressure, because of bigger shear stress due to the wider inner surface at the elliptical Y-jet nozzle. Larger SMD was measured on the elliptical Y-jet nozzle than the circular Y-jet nozzle. When SMD was measured in the X_Axis direction at the same gas mass flow rate, the elliptical Y-jet nozzle with an aspect ratio of 2:1 showed greater asymmetry than the others.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.933-939
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• 2010

The purpose of this study is to investigate the generation and development of cavitation in circular and elliptical nozzles. In order to investigate the influence of cavitation, the experiment was conducted with a set of elliptical nozzles that had the same cross-sectional area, different orifice aspect ratios (a/b). Each nozzle was made of acrylic so that visualization was possible. With the injection pressure, the internal flow of the nozzle was classified into the no-cavitation, cavitation, and hydraulic-flip regions. Regardless of the nozzle geometry, with the injection pressure, the flow rate in the no-cavitation and cavitation regions increased and the discharge coefficient decreased. However, the flow rate was constant in the hydraulic-flip region. In the elliptical nozzles, the generation and development of cavitation occurred at higher cavitation number than that in the case of a circular nozzle.