Title: A numerical study on the influence of liquid properties on gas-focused micro-jets

Authors: Rizwan Zahoor; Rok Regvar; Saša Bajt; Božidar Šarler

Addresses: Laboratory for Fluid Dynamics and Thermodynamics, Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, 1000 Ljubljana, Slovenia ' Laboratory for Fluid Dynamics and Thermodynamics, Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, 1000 Ljubljana, Slovenia ' Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany ' Laboratory for Fluid Dynamics and Thermodynamics, Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, 1000 Ljubljana, Slovenia; Laboratory for Simulation of Materials and Processes, Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana, Slovenia

Abstract: In this paper we present a numerical study on the influence of liquid properties on gas-focused micro-jets, such as used for sample delivery in serial femtosecond crystallography. The study is based on solving mixture formulation of Newtonian, compressible two-phase model with the finite volume method and algebraic volume of fluid for treatment of the phase-interface. The density, viscosity and surface tension of the focused fluid span around the material properties of pure water in the range of ±30%, thus representing a large range of possible sample delivery fluids. Fixed liquid and helium gas flow rates are used for jet focusing and the length, diameter, velocity and temperature of the jet are assessed as a function of material properties of the liquid. A thicker and slower jet is observed in case of increased density and surface tension of the focused fluid, while change in liquid viscosity has no effect on flow characteristics.

Keywords: gas dynamic virtual nozzle; GDVN; focusing gas; liquid properties; micro-jet; compressible multiphase flow; finite volume method; volume of fluid; jetting; dripping.

DOI: 10.1504/PCFD.2020.106407

Progress in Computational Fluid Dynamics, An International Journal, 2020 Vol.20 No.2, pp.71 - 83

Received: 28 Nov 2018
Accepted: 09 May 2019
Published online: 06 Apr 2020 *

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