Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: roztwór mocznika

Sortuj według:

Ogranicz wyniki do:

Numerical evaluation of urea-mixing devices for close-coupled selective catalytic reduction systems

Kaźmierski Bartosz Grzegorz, Kapusta Łukasz Jan

Combustion Engines

2023

R. 62, nr 2

84--93

The following research presents a numerical evaluation of existing and conceptual urea-mixing devices used in close-coupled (to the engine) selective catalytic reduction (SCR) systems. The analysis was aimed at the assessment of urea-mixing devices that could considerably enhance the reduction of nitrogen oxides from the diesel-engine combustion process under a wide range of operating conditions, including cold starts. The analysis showed that replacing blade-equipped static mixers with perforated stationary mixing devices may provide a more uniform spatial distribution of ammonia at the inlet to the SCR catalyst and reduce pressure drops generated by mixing devices. Moreover, the conceptual mixing devices, based on combinations of the blade and perforated mixers to develop intensive turbulence, enabled the increase of the mixing length leading to effective decomposition of the urea-water solution (UWS), and provided uniform spatial distribution of ammonia, even for the small-sized mixing systems. However, the intensive mixing was often associated with a significant rise in the pressure drop.

CFD Model of SNCR with Shifting Effect of CO

Blejchař T., Jablonská J., Szeliga Z., Zavila O., Konvička J., Regucki P., Krzyżyńska R.

Rocznik Ochrona Środowiska

2018

Tom 20, cz. 1

109--122

The paper deals with CFD simulation of SNCR technology with implemented CO temperature shift. The influence of CO on the SNCR process is described by empirical adjustment of kinetics parameters of chemical reactions. Results of CFD simulation were compared with results of experimental measurements. Although the proposed kinetics model of SNCR technology is simplified, it is able to describe reduction of NOx and other phenomena of SNCR with good precision. The model can be used to verify of injection levels and injection lances arrangement at design phase.

Artykuł przedstawia wyniki symulacji procesów SNCR z wykorzystaniem obliczeń CFD z uwzględnieniem przesunięcia temperaturowego związanego z obecnością CO oraz parametrów kinetycznych przedstawionych w tekście reakcji chemicznych. Wpływ CO na proces SNCR opisuje empiryczna korekta parametrów kinetyki reakcji chemicznych. Wyniki symulacji CFD porównano z wynikami pomiarów eksperymentalnych. Chociaż proponowany kinetyczny model technologii SNCR jest uproszczony, to jest w stanie opisać redukcję NOx, z uwzględnieniem wielu parametrów technologii SNCR, z dobrą precyzją. Opisany model może być wykorzystany na etapie projektowania instalacji SNCR uwzględniając m.in. miejsca iniekcji i układ lanc.

The influence of the injection frequency on the urea selective catalytic reduction systems performance

Rogóż R., Jaworski P., Kapusta Ł. J., Teodorczyk A.

Combustion Engines

2017

R. 56, nr 3

73--77

This study presents the influence of the UWS injection frequency on a close coupled SCR systems performance. The investigation was performed with the CFD tool AVL Fire. In the paper the analysis of four different UWS injection frequencies in the three different operating points of diesel engine was shown. The assessments of the system performance was referred to the ammonia distribution at catalyst intake and wall film formation inside the investigated geometry, as these are considered as crucial in such a configuration. The results showed that injection frequency affects both factors on different level depending from the flow conditions. In addition, the wall film crystallization risk was discussed basing on the obtained wall film characteristics.