Numerical Simulation of the Formation of Constricted Waterjets in Hydroentangling Nozzles

Anantharamaiah, Nagendra; Tafreshi, H. Vahedi; Pourdeyhimi, Behnam

doi:10.1205/cherd.05077

Cited by 20 publications

(10 citation statements)

References 13 publications

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“…This is because they stay laminar for a wider range of velocities and therefore they have a longer breakup length as compared to nonconstricted waterjets at the same pressures. Constricted waterjets may form either in nozzles with length-to-diameter ratios smaller than 0.7 (Anantharamaiah et al, 2006) (not the case of hydroentangling nozzles) or in any nozzle that undergoes a so-called "hydraulic flip". Hydraulic flip is the condition where cavitation cloud in a cavitating nozzle reaches the nozzle outlet and allows the downstream ambient air to flow inside the nozzle and envelop the waterjet.…”

Section: Hydroentangling Waterjetsmentioning

confidence: 99%

A study on flow through hydroentangling nozzles and their degradation

Anantharamaiah¹,

Tafreshi²,

Pourdeyhimi³

2006

Chemical Engineering Science

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Section: Hydroentangling Waterjetsmentioning

confidence: 99%

A study on flow through hydroentangling nozzles and their degradation

Anantharamaiah¹,

Tafreshi²,

Pourdeyhimi³

2006

Chemical Engineering Science

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“…The interfacial flow model used in this study was the VOF method along with the CSF model to consider the surface tension effect. The paper of Anantharamaiah et al (2006) provides extensive discussions of the effect of nozzle geometry on the formation of constricted waterjets, which have an air gap between the liquid and nozzle wall. In this study, the VOF method together with the CSF model was used as the two-phase flow model.…”

Section: Introductionmentioning

confidence: 99%

Influence of liquid hydrophobicity and nozzle passage curvature on microfluidic dynamics in a drop ejection process

Lai

Huang

Chen

et al. 2009

J. Micromech. Microeng.

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Employing methods of computational fluid dynamics, we investigated the physical phenomena and fluid dynamics of a microfluid during ejection of a droplet with a designed system of a nozzle plate connected to a flat-plate piezoelectric material. A comparison between experimental measurements and numerical simulations was devised to validate the theoretical model. The volume-of-fluid piecewise linear-interface construction (VOF-PLIC) interface-capturing method was adapted to represent the fluid domain and to track the evolution of its free boundaries whereas the continuous surface force (CSF) mode was chosen to model the interfacial physics. The results show that the curvature of the flow channel affects the velocity, period before disintegration, volume of the droplet and number of satellite drops. Increasing the diameter of the orifice increases the volume and decreases the velocity of the droplet. Increasing the amplitude or frequency of the nozzle plate raises the input energy, so increasing the velocity, decreasing the volume and hastening the disintegration of the droplet, but an increased amplitude or frequency increases the number of satellite drops. At the hydrophobic boundary, the velocity increases, the droplet volume decreases and the period before disintegration is abbreviated because of the decreased adhesive force between the fluid and the boundary surface.

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“…Anantharamaiah et al adopted and improved the design by adding components for adjusting the height as well and varying the jet pressure from 1000 to 3000 psi (6.89 to 20.68 MPa). 19 Their results established that the waterjet impact force was linearly proportional to the velocity and flow rate as long as the jet remains coherent and laminar. If the jet broke up and became a spray, its impact force was reduced.…”

mentioning

confidence: 94%

“…Begenir and colleagues, 2,16 Ghassemieh et al, 3 and others employed specially designed rigs as substitutes for the hydroentanglement machines in their experiments. [17][18][19] Ghassemieh et al measured the waterjet impact force of a single waterjet using a modified apparatus, 3 consisting of a laboratory setup, to measure the magnitude of the force with the waterjet nozzle operating between 3 to 12 MPa. Begenir used a design which closely resembled the industrial unit in her experimental set-up operated at high waterjet pressures of up to 400 bar.…”

mentioning

confidence: 99%

Studies on waterjet impact forces in the hydroentanglement process

Moyo

Anandjiwala

2013

Textile Research Journal

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In the hydroentanglement process, high velocity multiple waterjets are generated through the nozzles before impinging on the hydroentangling belt or fibre-web and exert an impact force. In this study, a technique to measure important characteristics of the waterjets, namely, the coefficient of velocity, Cv, and coefficient of discharge, Cd, is proposed. The technique offers a simple and practical method to determine the energy transfer efficiency from the manifold to the waterjets. The measured Cv and Cd values were observed to decrease with an increase in waterjet pressure, which implied higher energy losses at higher waterjet pressures. These results were then used in the next experiment to measure the waterjet impact force. The waterjet impact force was measured using a Tensiometer-R2000 fixed on a vibration-free stand at different waterjet pressures, varied from 30 to 120 bar. It was observed that the waterjet impact forces were equal across the width of the machine at a given pressure, but increased proportionally with the increase in the waterjet pressure. When the empirical relation was fitted between experimental and theoretical values of waterjet impact force, it was found that theoretical values were overestimated.

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Numerical Simulation of the Formation of Constricted Waterjets in Hydroentangling Nozzles

Cited by 20 publications

References 13 publications

A study on flow through hydroentangling nozzles and their degradation

A study on flow through hydroentangling nozzles and their degradation

Influence of liquid hydrophobicity and nozzle passage curvature on microfluidic dynamics in a drop ejection process

Studies on waterjet impact forces in the hydroentanglement process

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