A numerical study of gas focused non-Newtonian micro-jets

Zahoor, Rizwan (author), Bajt, Saša (author), Šarler, Božidar (author)

The present numerical study assesses the jet length, diameter and velocity of various non-Newtonian power-law fluids of a gas dynamic virtual nozzle. A related two-phase flow problem is formulated within the mixture framework and solved with the finite volume method and volume of fluid interface treatment in axisymmetry. The process parametric range allows the incompressible laminar flow assumption. A comprehensive jet characteristics analysis is carried out in a typical micro-nozzle configuration for a range of shear-thinning to shear-thickening fluids with power law indices 0.5 ≤ n < 1.5, gas mass flow rate of 10 mg/min and liquid volumetric flow rate of 43 µl/min, resulting in a gas Reynolds number of 130 with Reynolds and Weber numbers for a reference water jet being 90 and 10, respectively. It is observed that jets from shear-thinning fluids (0.5 ≤ n < 1.0) tend to be thicker, longer, and slower when compared with the shear-thickening fluids (1.0 < n ≤ 1.5). A dripping-jetting phase diagram of the nozzle is constructed by varying the power law index, gas and liquid flow rates in the range 0.9–1.1, 5–15 mg/min and 5–50 µl/min, respectively. It is observed that the area of stable jetting decreases with the increase of the power law index. The obtained novel information on the behaviour of non-Newtonian gas-focused micro-jets provides a possible new dimension for tailoring the serial crystallography sample delivery systems where the micro-jets carry dispersed crystals into an X-ray beam.

• Language: English
• Keywords: serial crystallography, micro jets, multiphase flow, fluid rheology, non-Newtonian fluid, flow focusing, gas dynamic virtual nozzle, liquid jets, power law, shear thinning, shear thickening
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 16 str.
• Numbering: Vol. 170, art. 104628
• PID: 20.500.12556/RUL-151690
• UDC: 532:519.6
• ISSN on article: 0301-9322
• DOI: 10.1016/j.ijmultiphaseflow.2023.104628
• COBISS.SI-ID: 168605443
• Publication date in RUL: 16.10.2023

Record is a part of a journal

• Title: International journal of multiphase flow
• Shortened title: Int. j. multiph. flow
• Publisher: Elsevier
• ISSN: 0301-9322
• COBISS.SI-ID: 25649408

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: serijska kristalografija, mikrocurki, večfazni tok, reologija toka, nenewtonska tekočina, fokusiranja toka