Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Refine search results

Journals help

  1. 1 Chemical and Process Engineering

  2. 1 Nukleonika

Years help

  1. 2 2015

Authors help

  1. 2 Rożeń A.

Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 2

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

100%
Rożeń A.
Chemical and Process Engineering
|
2015
|
vol. 36
|
issue 1
3-19
EN
: A passive autocatalytic hydrogen recombiner (PAR) is a self-starting device, without operator action or external power input, installed in nuclear power plants to remove hydrogen from the containment building of a nuclear reactor. A new mechanistic model of PAR has been presented and validated by experimental data and results of Computational Fluid Dynamics (CFD) simulations. The model allows to quickly and accurately predict gas temperature and composition, catalyst temperature and hydrogen recombination rate. It is assumed in the model that an exothermic recombination reaction of hydrogen and oxygen proceeds at the catalyst surface only, while processes of heat and mass transport occur by assisted natural and forced convection in non-isothermal and laminar gas flow conditions in vertical channels between catalyst plates. The model accounts for heat radiation from a hot catalyst surface and has no adjustable parameters. It can be combined with an equation of chimney draft and become a useful engineering tool for selection and optimisation of catalytic recombiner geometry.
2
Content available remote

Modelling of a passive autocatalytic hydrogen recombiner – a parametric study

100%
Rożeń A.
|
|
issue 1
161-169
EN
Operation of a passive autocatalytic hydrogen recombiner (PAR) has been investigated by means of computational fluid dynamics methods (CFD). The recombiner is a self-active and self-adaptive device used to remove hydrogen from safety containments of light water nuclear reactors (LWR) by means of a highly exothermic reaction with oxygen at the surface of a platinum or palladium catalyst. Different turbulence models (k-ω, k-ɛ, intermittency, RSM) were applied in numerical simulations of: gas flow, heat and mass transport and chemical surface reactions occurring in PAR. Turbulence was found to improve mixing and mass transfer and increase hydrogen recombination rate for high gas flow rates. At low gas flow rates, simulation results converged to those obtained for the limiting case of laminar flow. The large eddy simulation technique (LES) was used to select the best RANS (Reynolds average stress) model. Comparison of simulation results obtained for two- and three-dimensional computational grids showed that heat and mass transfer occurring in PAR were virtually two-dimensional processes. The effect of hydrogen thermal diffusion was also discussed in the context of possible hydrogen ignition inside the recombiner.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.