Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1239526 | Spectrochimica Acta Part B: Atomic Spectroscopy | 2016 | 12 Pages |
•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.