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The choice R(u) = u(1 − u) yields Fisher's equation that was originally used to describe the spreading of biological populations, [3] the Newell–Whitehead-Segel equation with R(u) = u(1 − u 2) to describe Rayleigh–Bénard convection, [4] [5] the more general Zeldovich–Frank-Kamenetskii equation with R(u) = u(1 − u)e-β(1-u) and 0 ...
This is a list of software used to simulate the material and energy balances of chemical process plants. Applications for this include design studies, engineering studies, design audits, debottlenecking studies, control system check-out, process simulation, dynamic simulation, operator training simulators, pipeline management systems, production management systems, digital twins.
Diffusion-controlled (or diffusion-limited) reactions are reactions in which the reaction rate is equal to the rate of transport of the reactants through the reaction medium (usually a solution). [1] The process of chemical reaction can be considered as involving the diffusion of reactants until they encounter each other in the right ...
The self-diffusion coefficient of neat water is: 2.299·10 −9 m 2 ·s −1 at 25 °C and 1.261·10 −9 m 2 ·s −1 at 4 °C. [2] Chemical diffusion occurs in a presence of concentration (or chemical potential) gradient and it results in net transport of mass. This is the process described by the diffusion equation.
The convection–diffusion equation can be derived in a straightforward way [4] from the continuity equation, which states that the rate of change for a scalar quantity in a differential control volume is given by flow and diffusion into and out of that part of the system along with any generation or consumption inside the control volume: + =, where j is the total flux and R is a net ...
The diffusion equation is a parabolic partial differential equation. In physics, it describes the macroscopic behavior of many micro-particles in Brownian motion , resulting from the random movements and collisions of the particles (see Fick's laws of diffusion ).
The laminar finite rate model computes the chemical source terms using the Arrhenius expressions and ignores turbulence fluctuations. This model provides with the exact solution for laminar flames but gives inaccurate solution for turbulent flames, in which turbulence highly affects the chemistry reaction rates, due to highly non-linear Arrhenius chemical kinetics.
A chemical computer, also called a reaction-diffusion computer, Belousov–Zhabotinsky (BZ) computer, or gooware computer, is an unconventional computer based on a semi-solid chemical "soup" where data are represented by varying concentrations of chemicals. [1] The computations are performed by naturally occurring chemical reactions.