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PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING
Edited by: B.H.V. Topping and Y. Tsompanakis
Modelling of Chemical Reactors using Supercomputers
Institute of Computational Mathematics and Mathematical Geophysics, SB RAS, Novosibirsk, Russia
I.G. Chernykh, "Modelling of Chemical Reactors using Supercomputers", in B.H.V. Topping, Y. Tsompanakis, (Editors), "Proceedings of the Thirteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 119, 2011. doi:10.4203/ccp.96.119
Keywords: computer simulation, computational fluid dynamics, chemical kinetics, reaction engineering.
The numerical modelling of fluid flows and chemical processes in chemical reactors plays an important role in the development of new facilities as well as the upgrading of existing chemical processes and chemical reactors.
This paper presents the optimization of reactor prototypes and chemical processes that were described in . The results of the numerical modelling using computational fluid dynamics (CFD) with laser energy input of new chemical reactors for ethane pyrolysis process research are presented. An optimal kinetics scheme was computed with the use of the ChemPAK  software package. The reactions were conducted under homogeneous conditions at atmospheric pressure in the reactor with the reaction mixture components heated by the laser energy flux delivered directly into the gas. Ethylene, being among the main reaction products, served as the laser energy absorber. Here, increasing energy absorption in the volume is related to the increased content of the reaction product. The reactor design helps to shield the optical window and mirror from pollution by the products of the chemical reaction. This mode was known as 'energetic catalysis' in literature during the 1980s. Now this technology provides new possibilities for controlling chemical processes in chemical reactors, because the temperature in the reaction zone of reactor can be changed rapidly. Also modern laser power generators have more power efficiency and more flexible prices than in the 1980s.
Complex three-dimensional modelling of physical processes in chemical reactors is a very important problem. FLUENT  has been used for numerical modelling. The parameters of the modelling are: laminar flow for viscous effects, species transport with chemical reactions, a discrete ordinates (DO) model for radiation, and a steady time solver. Also some user defined functions (UDFs) were developed for modelling the laser the energy absorption by the C2H4 in the reactants mixture. Modelling of the laser radiation energy in FLUENT has some problems because the DO model depends on the position and rotation of the geometry. Acceptable parameters of the discretization for the DO model increase the memory usage. For a 24GB. 4 x Itanium 2 workstation with 64 gigabytes of RAM the calculation time was about one hour.
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