Study of the secondary droplet breakup mechanism and regime map of Newtonian and power law fluids at high liquid–gas density ratio

Kant, Krishna and Banerjee, Raja (2022) Study of the secondary droplet breakup mechanism and regime map of Newtonian and power law fluids at high liquid–gas density ratio. Physics of Fluids, 34 (4). pp. 1-25. ISSN 1070-6631

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Abstract

This work reports the numerical investigation of the secondary breakup of non-Newtonian droplets at different Weber W e g and Ohnesorge O h l numbers. As part of this work, an in-house coupled level set volume of fluid solver is developed based on OpenFOAM libraries. It uses improved curvature calculation techniques like smoothening and the closest point search method. Flow is assumed to be axisymmetric. Approximately 95 different cases were simulated to investigate the effect of W e g and O h l numbers on secondary breakup for Newtonian, shear-thinning, and shear-thickening fluids. O h l varies from 10 - 3 to 10 1, and, correspondingly, W e g varies from 10 1 to 10 3. The non-Newtonian rheology is modeled as a power-law fluid, and the power-law index n ranged from 0.2 - 1.8. The present work describes the flow field near the droplet and the effects of non-Newtonian parameters and viscosity on the flow field. The various aspects of droplet dynamics like droplet deformation ratio y, deformation rate y ˙, and coefficient of pressure C p are studied and compared with the internal flow theory. A generalized relation for critical Weber number W e g, c r is proposed for both Newtonian and non-Newtonian fluids and is shown in a phase diagram plot to map the different regimes of secondary droplet breakup. © 2022 Author(s).

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IITH Creators:

IITH Creators	ORCiD
Banerjee, Raja	http://orcid.org/0000-0002-7163-1470

Item Type:

Article

Additional Information:

The authors would like to acknowledge the financial support by the Ministry of Education, Government of India, to Mr. K. Kant. The authors thank Dr. H. N. Dixit for providing access to computational resources from his group to simulate some of the cases reported in this work and Mr. M. Pandecheri for his technical support in using the computational hardware and software used in this work.

Uncontrolled Keywords:

Breakup regimes; Droplet break-up mechanisms; Gas density ratios; Mechanism maps; Newtonian and power law fluids; Newtonians; Non-newtonian; Regime map; Secondary breakup; Secondary droplets

Subjects:

Physics > Mechanical and aerospace

Divisions:

Department of Mechanical & Aerospace Engineering

Depositing User:

. LibTrainee 2021

Date Deposited:

13 Jul 2022 10:43

Last Modified:

13 Jul 2022 10:43

URI:

http://raiithold.iith.ac.in/id/eprint/9473