Laminar Finite-rate Model Research Articles

Fluid/thermal/chemical non-equilibrium simulation of hypersonic reentry vehicles

A multi-physics frame work has been setup for the simulation of surface heat flux for nonablating hypersonic reentry vehicles and presented in this paper. The main goal of this work was to set up a simple approach for the heat flux prediction during the reentry of the vehicle. The vehicle considered in the calculation is an axisymmetric vehicle flying at zero degree angle of attack. Chemical nonequilibrium in the flowfield is simulated by implementing a set of finite rate equations in the laminar finite rate model in FLUENT. The frame work set up was validated with the results available in the literature. Good correlation was observed between the results from the commercial code with the implemented equations and the results from the literature.

Computational Fluid Dynamics Simulation of Gas−Solid Flow during Steam Reforming of Glycerol in a Fluidized Bed Reactor

A computational fluid dynamics simulation of gas-solid flow in a fluidized bed reactor was performed to investigate the steam reforming of glycerol using a three-step reaction scheme, motivated by the worldwide increase of crude glycerol produced by the transesterification of vegetable oil into biodiesel. The Eulerian-Eulerian two-fluid approach was adopted to simulate hydrodynamics of fluidization, and chemical reactions were modeled by the laminar finite-rate model. The gas-solid system exhibited a more heterogeneous structure. Clusters were observed to fall and stack together along the wall, and the process of wall slug formation was very evident. This suggests the bed should be agitated to maintain satisfactory fluidizing conditions. The results showed that the glycerol conversion increased with increasing reaction time, and most of the gas products-H2, CO2, CH4, and CO-were formed during the initial 2 s. The prediction of the gas-solid phase flows and mixing, glycerol conversion, and products distribution will provide helpful data to design and operate a bench-scale catalytic fluidized bed reactor.

Finite volume method as the numerical method for new emulsion polymerization tubular reactor with internal angle baffles

A finite volume method is used to solve a determinist mathematical model and to analyze the performance of an alternative design for an emulsion polymerization reactor with internal angular baffles as static mixer. It is assumed to be a steady-state, cylindrical one-dimensional model having a fully developed laminar plug flow. The Smith-Ewart model is used to estimate the monomer conversion, the kinetics is of Arrhenius type, and laminar finite-rate model is assumed to compute chemical source terms. The objective of this work is to develop the finite volume method for the new emulsion polymerization tubular reactor with internal angle baffles. The performance of the alternative reactor is compared with continuous tubular reactor with constant reaction temperature. The simulations were validated with experimental results for the isothermal and tubular reactor, with a good concordance. The results with baffles were better than without baffles in relation to desired properties such as particle size and viscosity. The problem is sufficiently well solved by finite volume method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6037–6048, 2006