A numerical investigation of micro-jet characteristics in different pressure environments
Rizwan Zahoor, S. Bajt, Božidar Šarler
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.