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Abstract. The paper deals with numerical simulation of SNCR method. For numerical modelling was used CFD code Ansys/CFX. SNCR method was described by dominant chemical reaction, which were look up NIST Chemical database. The reactions including reduction of NOx and concentration change of pollutants, like N2O and CO in flue gas too. Proposed chemical kinetics and CFD model was applied to two boilers. Both simulations were compared with experimental measurements. First simulation was used to validation of chemical mechanism. Second simulation was based on first simulation and it was used to verification of compiled SNCR chemical mechanism. Next the new variant of the reagent penetration lance was proposed and compared with the original variants.

SNCR (Selective non-catalytic reduction) Technology is currently being used to reach the emission limit for nitrogen oxides at fossil fuel fired power plant and/or heating plant and optimum temperature for SNCR process is in range 850 - 1050°C. Modified SNCR technology is able to reach reduction 60% of nitrogen oxides at temperature up to 1250°C. So the technology can also be installed where the flue gas temperature is too high in combustion chamber. Modified SNCR was tested using generally known SNCR chemistry implemented in CFD (Computation fluid dynamics) code. CFD model was focused on detail simulation of reagent injection and influence of flue gas temperature. Than CFD simulation was compared with operating data of boiler where the modified SNCR technology is installed. By comparing the experiment results with the model, the effect on nitrous oxides removal process and temperature of flue gas at the injection region.

Abstract. The availability of reliable modeling tools and input data required for the prediction of surface removal rate from the lithium fl uoride targets irradiated by the intense photon beams is essential for many practical aspects. This study is motivated by the practical implementation of soft X-ray (SXR) or extreme ultraviolet (XUV) lasers for the pulsed ablation and thin fi lm deposition. Specifi cally, it is focused on quantitative description of XUV laser-induced desorption/ablation from lithium fl uoride, which is a reference large band-gap dielectric material with ionic crystalline structure. Computational framework was proposed and employed here for the reconstruction of plume expansion dynamics induced by the irradiation of lithium fl uoride targets. The morphology of experimentally observed desorption/ablation craters were reproduced using idealized representation (two-zone approximation) of the laser fl uence profi le. The calculation of desorption/ablation rate was performed using one-dimensional thermomechanic model (XUV-ABLATOR code) taking into account laser heating and surface evaporation of the lithium fl uoride target occurring on a nanosecond timescale. This step was followed by the application of two-dimensional hydrodynamic solver for description of laser-produced plasma plume expansion dynamics. The calculated plume lengths determined by numerical simulations were compared with a simple adiabatic expansion (blast-wave) model.

The systems with fluidic oscillators are intensively studied nowadays because the oscillatory flow can increase heat and mass transfer and decrease energy dissipation. Fluidic oscillators produce an active-type mixing enhancement but in a passive manner as they do not require any moving parts. They convert steady pressurized inlet flow to oscillatory or pulsatile flow at an outlet without the need for external power. In general, there are many types of fluidic oscillators, categorized by the underlying mechanism to create oscillatory output behaviour. The fluidic oscillator with the single feedback loop is analysed in this paper. A numerical simulation of oscillating flow is performed and two approaches for modelling flow, RANS, and LES are applied especially. The results of numerical simulation are compared with experimental measurement. The analysis is focused on pressure drop and oscillation frequency dependent on the inlet conditions. The energy spectrum of oscillating flow is analysed using discrete Fourier transform.