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

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.