An Analytical Approach for Calculation of Critical Weber Number of Droplet Breakup in Turbulent Gaseous Flows

Omidvar, Amir; Khaleghi, Hassan

doi:10.1007/s13369-012-0319-x

Cited by 10 publications

(7 citation statements)

References 20 publications

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“…The investigated parameters are the axial spray tip penetration, spray cone angle, spray width, nozzle discharge coefficient, Weber number, Reynolds number and vortex clouds. The discharge coefficient, Weber number and Reynolds number are given by [ 8 ]

…”

Section: Methodsmentioning

confidence: 99%

Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

Naz

Sulaiman

Ariwahjoedi

et al. 2013

The Scientific World Journal

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The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit.

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…”

Section: Methodsmentioning

confidence: 99%

Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

Naz

Sulaiman

Ariwahjoedi

et al. 2013

The Scientific World Journal

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“…The present model is a new modification for almost all secondary breakup models, which was introduced firstly by Omidvar and Khaleghi. 25 This model considers the effects of the gas phase turbulence on the secondary breakup process. This modification enhances the critical Weber number by changing breakup characteristic time.…”

Section: Theory and Equationsmentioning

confidence: 99%

“…To add the effects of gas turbulence on the secondary breakup of droplets, the relative velocity between gas and droplet, that is, | u g − u d | , is replaced by effective relative velocity u rel , eff to compensate for the variations in the critical Weber number: 25…”

Section: Theory and Equationsmentioning

confidence: 99%

“…Where I r represents turbulence intensity. Omidvar and Khaleghi 25 proposed to calculate turbulent length l , given that only eddies with the same size order as droplet’s diameter can affect the surface of the droplet. They took l = π D for turbulent length, where D is the droplet diameter.…”

Section: Theory and Equationsmentioning

confidence: 99%

“…In 2011, the effects of turbulence on the secondary breakup of droplets were theoretically shown by Han et al 23 In 2012, Nagy et al 24 by studying computationally on the breakup of droplets, showed that turbulence plays a vital role in breakup at high Weber numbers. In the same year, Omidvar and Khaleghi 25 proposed an analytical approach for prediction of critical Weber number considering ambient turbulence and density ratio effects. They imposed the effects of turbulent flow by introducing a hybrid time scale, which is a combination of laminar and turbulent timescales.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Turbulence on the secondary breakup of droplets in diesel fuel sprays

Khaleghi

Sani

Ahmadi

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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In this paper, the importance of turbulence effects on the procedure of droplet’s secondary breakup is studied. In the process of modeling the secondary breakup of a droplet, it is a common practice to presume that the droplet is moving in a laminar flow. However, it is evident that the critical Weber number is profoundly affected by the intensity of turbulence presented in the flow. As a result, the abovementioned supposition may lead to significant computational inaccuracy. This paper tends to perform a modification that considers the effects of turbulent flow on the secondary breakup of droplets. It is shown that the results obtained by the modified model are more precise and in a better agreement with experimental data. In this paper, spray behavior is predicted by a conventional breakup model and the one obtained by a modified model, which are both implemented in an in-house computer code. This CFD code accounts for engine simulation by solving the governing two-phase-flow equations using the Eulerian-Lagrangian approach in a three-dimensional coordinate system. To show the effects of turbulence, the changes in spray parameters such as droplet size distribution, spray tip penetration, and spray mean diameter, which is extracted from the two models are compared. Results have shown that the turbulence causes droplets to break in an earlier time, which leads to a higher rate of evaporation and lower penetration length. An interesting fact concluded in this paper is that the difference between the results of the two models decreases as the gas pressure is increased, which means the effects of turbulence become less important as the gas pressure increases.

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Qualitative Study on Parameters Affecting the Structure of Sprays and Its Atomization

Gade

Baraiya

2022

Lecture Notes in Mechanical Engineering

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An Analytical Approach for Calculation of Critical Weber Number of Droplet Breakup in Turbulent Gaseous Flows

Cited by 10 publications

References 20 publications

Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

Effects of Turbulence on the secondary breakup of droplets in diesel fuel sprays

Qualitative Study on Parameters Affecting the Structure of Sprays and Its Atomization

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