Title: A numerical investigation of micro-jet characteristics in different pressure environments

Authors: Rizwan Zahoor; Saša Bajt; Božidar Šarler

Addresses: Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, 1000 Ljubljana, Slovenia ' Deutsches Elektronen-Synchrotron DESY, Notkestraβe 85, 22607 Hamburg, Germany; The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany ' Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, 1000 Ljubljana, Slovenia; Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana, Slovenia

Abstract: The performance of gas focused micro-jets is measured in terms of stability, length, thickness, and speed. Such jets found use in serial femtosecond crystallography (SFX) experiments performed at atmospheric pressure or in vacuum. In this study, a numerical investigation of the influence of environmental pressure on micro-jet performance is presented. The solution of the laminar, Newtonian, liquid-gas two-phase compressible model is sought within the finite volume method and the volume of fluid framework. The study is conducted for constant liquid and gas flow rates of 22 µl/min and 57 mg/min. The outlet pressure is varied from 0.15 kPa to 101 kPa, and the related performance is analysed. As desired for SFX experiments, we find that an outlet pressure of 10 kPa provides an extended jet without compromising its diameter and velocity. The numerical study gives the experimentalists an insight into how the nozzle operates over a range of outlet pressures.

Keywords: gas dynamic virtual nozzle; outlet pressure; micro-jet; jet shape; jet velocity; multiphase flows; coupled numerical model.

DOI: 10.1504/IJHM.2021.120618

International Journal of Hydromechatronics, 2021 Vol.4 No.4, pp.368 - 383

Received: 23 Jul 2021
Accepted: 20 Nov 2021
Published online: 28 Jan 2022 *

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