Effects of aspect ratio on the flow development of rectangular liquid jets issued into stagnant air

Tadjfar, Mehran; Jaberi, Amin

doi:10.1016/j.ijmultiphaseflow.2019.03.011

Cited by 32 publications

(13 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The flow development of rectangular liquid jets with different aspect ratios was experimentally and theoretically studied by the authors. 13 It was revealed that in contrast to the previous findings, aspect ratio has a significant impact on axis-switching characteristics of rectangular jets. Also, a theoretical model was proposed that, by considering the jet aspect ratio and flow condition, could successfully estimate the wavelength of axis-switching.…”

Section: Introductioncontrasting

confidence: 58%

Comparative study on interfacial oscillations of rectangular and elliptical liquid jets

Jaberi

Tadjfar

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

The instability characteristics and flow structures of water jets injected from rectangular and elliptical nozzles with aspect ratios varying from 2 to 6 were experimentally studied and compared. Shadowgraph technique was employed for flow visualization, and structures on the liquid jet surface were captured using high speed photography. It was found that disturbances originating from the nozzle geometry initially perturbed the liquid column, and then, at high jet velocities, disturbances generated within the flow dominated the jet surface. It was also found that rectangular nozzles introduced more disturbances into the flow than the elliptical ones. The characteristic parameters of axis-switching phenomenon including wavelength, frequency, and amplitude were measured and compared. Axis-switching wavelength was found to increase linearly with Weber number. Also, the wavelengths of rectangular jets were longer than the elliptical jets. Further, the frequency of axis-switching was shown to be reduced with increase of both Weber number and aspect ratio. It was observed that the axis-switching amplitude increased monotonically, reached a peak, and then decreased gradually. It was also found that the axis-switching amplitude varied with Weber number. At lower values of Weber number, the rectangular nozzles had higher amplitude than the elliptical nozzles. However, at higher values of Weber number, this relation was reversed, and the elliptical nozzles had the higher axis-switching amplitudes. This reversal Weber number decreased with the orifice aspect ratio. The reversal Weber number for aspect ratio of 4 was about 289, and it had decreased to 144 for the aspect ratio of 6.

show abstract

Section: Introductioncontrasting

confidence: 58%

Comparative study on interfacial oscillations of rectangular and elliptical liquid jets

Jaberi

Tadjfar

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

show abstract

“…The resulting camera image of the illuminated flow is called a shadowgram. With shadowgraphy it is possible to evaluate the free jet shape of the coolant supply [17]. A shadowgram of the coolant supply flow from the nozzle to the interaction with the rotating grinding wheel is shown in Fig.…”

Section: State Of the Artmentioning

confidence: 99%

Optical Flow Field Measurements of The Coolant In A Grinding Machine

Espenhahn

Schumski

Vanselow

et al. 2021

Preprint

View full text Add to dashboard Cite

Since the cooling mechanism of industrial grinding is not yet fully understood, a measurement of the coolant liquid flow field near the grinding wheel is desired. However, the curved surfaces of the liquid phase result in unpredictable light deflections and reflections, which impedes optical flow measurements. In order to obtain qualitative and quantitative information regarding the flow velocity field of the coolant liquid, shadowgraphy in combination with a pattern correlation technique as well as particle image velocimetry are applied in a grinding machine and studied with respect to their measurement capabilities. Particle image velocimetry enables flow measurements inside the laminar coolant jet, whereby the shadowgraph imaging velocimetry complements these measurements and is in particular suitable for spray-like flow regimes. As a result, optical flow field measurements of the coolant flow in a grinding machine are shown to be feasible, which is required to understand the flow mechanisms that affect the grinding cooling process.

show abstract

“…As a classic fluid problem [38][39][40], the rectangular waterjet also plays an important role in the research on flood discharge atomization [14]. Therefore, the constricted nozzle was designed with a rectangular outlet, including three sections along the flow direction: Section 1 is a circle-to-square transition region for connecting the upstream water pipe (D = 20 cm), Section 2 is a contraction section (12.50 cm wide × 12.50 cm high to 10.00 cm wide × 3.00 cm high) for improving the velocity, and Section 3 is a rectifying section (10.00 cm wide × 3.00 cm high) for producing a regular waterjet; the sections are 30.00 cm, 25.00 cm, and 20.00 cm long, respectively, as shown in Figure 2b.…”

Section: Design and Regulation Of Experimental Platformmentioning

confidence: 99%

An Experimental Study on the Effects of Atomized Rain of a High Velocity Waterjet to Downstream Area in Low Ambient Pressure Environment

Liu

Lian

Liu

et al. 2020

Water

View full text Add to dashboard Cite

A better understanding of the atomized rain characteristics in low ambient pressure areas is beneficial in reducing the jeopardizing effect of flood discharge atomization on high-altitude hydropower stations. A random splash experiment is designed with two measurement planes to investigate the effects of low ambient pressure on downstream atomized rain under the complicated conditions of low ambient pressure (within 0.60P0~1.00P0) and high waterjet velocity (at a magnitude of 10 m/s). The results demonstrate that the atomized rain (rain intensity ≥ 2 mm/h) downstream, characterized by two-dimensional distribution, can be enhanced by decreasing the ambient pressure and by increasing the inflow discharge. When the ambient pressure decreases at the same inflow discharge, both the distance of the rain intensity lines (40 mm/h, 10 mm/h, 2 mm/h) in the horizontal plane from the constricted nozzle outlet and the average rain amount in the inclined plane within the atomized source ratio of ((0~30) × 10−3)% appear as “linear” growth. With the ambient pressure decreasing by 0.10P0, the range of those characteristic rain intensity lines is expanded by 0.68%~1.37%, and the average rain amount is enlarged by 11.06%~20.48%. When keeping the low ambient pressure unchanged, both the point average rain intensity reduction along the releasing centerline and the surface average rain amount growth with increased inflow discharge all follow an exponential function. The aeration reduction in the waterjet boundary and the resistance reduction in atomized water-droplets are contributing factors for the enhancement effect of low ambient pressure. This study can enable the establishment of a foundation to further predict flood discharge atomization in a high-altitude environment.

show abstract

Effects of aspect ratio on the flow development of rectangular liquid jets issued into stagnant air

Cited by 32 publications

References 25 publications

Comparative study on interfacial oscillations of rectangular and elliptical liquid jets

Comparative study on interfacial oscillations of rectangular and elliptical liquid jets

Optical Flow Field Measurements of The Coolant In A Grinding Machine

An Experimental Study on the Effects of Atomized Rain of a High Velocity Waterjet to Downstream Area in Low Ambient Pressure Environment

Contact Info

Product

Resources

About