The paper presents a description of selected models dedicated to steam condensing flow modelling. The models are implemented into an in-house computational fluid dynamics code that has been successfully applied to wet steam flow calculation for many years now. All models use the same condensation model that has been validated against the majority of available experimental data. The state equations for vapour and liquid water, the physical model as well as the numerical techniques of solution to flow governing equations have been presented. For the single-fluid model, the Reynolds-averaged Navier-Stokes equations for vapour/liquid mixture are solved, whereas the two-fluid model solves separate flow governing equations for the compressible, viscous and turbulent vapour phase and for the compressible and inviscid liquid phase. All described models have been compared with relation to the flow through the Laval nozzle.
Samples of steam coal used in heat and power plants as well as densimetric fractions obtained on a laboratory scale by dense organic liquid separation have been examined. The contents of ash, mercury, chromium, cadmium, copper, nickel and lead have been determined in coal, in the light and medium fraction as well as in the refuse. The degree of removal of mineral matter and the examined heavy metals as well as the coal combustible parts yield have been determined. Examination of 5 coals revealed that it is possible to remove 41% of mercury and more than 35% of other heavy metals bound to mineral matter in coal.