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Mathematical modeling of hydrogen production performance in thermocatalytic reactor based on the intermetallic phase of Ni3Al

Badur Janusz, Stajnke Michał, Ziółkowski Paweł, Jóźwik Paweł, Bojar Zbigniew, Ziółkowski Piotr Józef

Archives of Thermodynamics

2019

Vol. 40, no 3

3--26

The main goal of the considered work is to adjust mathematical modeling for mass transfer, to specific conditions resulting from presence of chemical surface reactions in the flow of the mixture consisting of helium and methanol. The thermocatalytic devices used for decomposition of organic compounds incorporate microchannels coupled at the ends and heated to 500ºC at the walls regions. The experiment data were compared with computational fluid dynamics results to calibrate the constants of the model’s user defined functions. These extensions allow to transform the calculations mechanisms and algorithms of commercial codes adapting them for the microflows cases and increased chemical reactions rate on the interphase between fluid and solid, specific for catalytic reactions. Results obtained on the way of numerical calculations have been calibrated and compared with the experimental data to receive satisfactory compliance. The model has been verified and the performance of the thermocatalytic reactor with microchannels under hydrogen production regime has been investigated.

Transport phenomena in saturated porous media undergoing liquid-solid phase change

Geindreau C., Auriault J.-L.

Archives of Mechanics

2001

Vol. 53, nr 4-5

385-420

The macroscopic modelling of transport phenomena occurring during the solidification process in porous media is revisited in this paper. The particular case of binary phase change in metallic alloys is considered. Continuum models for momentum, mass, heat and species transport in metallic saturated porous media undergoing liquid-solid phase change are derived from the description at the pore scale by using an upscaling technique. We use the method of multiple scale expansions which gives rigorously the macroscopic behaviour. Different macroscopic descriptions are derived in function of the orders of magnitude of dimensionless numbers that characterize the dominating phenomena and the physical properties of the constituents at the microscopic scale. Among the distinct homogenizable situations, the three richest cases are presented in this paper. The domains of validity of the micro-macrosegregation models, i.e. lever-rule type models and Scheil type models, are shown by means of the order of magnitude of dimensionless numbers. The continuous passage between the different models is investigated.