Three-dimensional time-dependent computer modeling of the electrothermal atomizers for analytical spectrometry

•Complete 3D transient model of various electrothermal atomizers was developed.•Model can predict atomic absorbance signal for given optical detector.•Atomization of three chemical elements were modeled: Ag, Cu, In.•Periodical reverse gas flow (10 Hz) occurs in the THGA in variety of time steps.•The tungsten helix atomizer looks like a solid cylinder for upstream shielding gas.

A full three-dimensional nonstationary numerical model of graphite electrothermal atomizers of various types is developed. The model is based on solution of a heat equation within solid walls of the atomizer with a radiative heat transfer and numerical solution of a full set of Navier–Stokes equations with an energy equation for a gas. Governing equations for the behavior of a discrete phase, i.e., atomic particles suspended in a gas (including gas-phase processes of evaporation and condensation), are derived from the formal equations molecular kinetics by numerical solution of the Hertz–Langmuir equation. The following atomizers test the model: a Varian standard heated electrothermal vaporizer (ETV), a Perkin Elmer standard THGA transversely heated graphite tube with integrated platform (THGA), and the original double-stage tube-helix atomizer (DSTHA). The experimental verification of computer calculations is carried out by a method of shadow spectral visualization of the spatial distributions of atomic and molecular vapors in an analytical space of an atomizer.