Exothermic and endothermic chemical reactions involving very many particles mode

2019-11-12 15:20:40

potential particles chemical reactions endothermic

责任者: Alda, W.;Yuen, D.A.;Luthi, H.-P.;Rustad, J.R. 单位: Inst. of Comput. Sci., Univ. of Min. & Metall., Krakow, Poland 来源出处: Physica D(Physica D (Netherlands)),2000/11/15,146(1-4):261-74 摘要: The traditional continuum approach of modeling chemical reactions with specified kinetic rates suffers from numerical difficulties in reactive flows and other highly non-equilibrium situations due to the stiffness of the differential equations in both space and time. These drawbacks can be eliminated within the framework of the discrete-particle approach in which the chemical reactions are modeled by means of two-body interparticle potentials with classical molecular dynamics. Here we present a simple model for prescribing the binary endothermic and exothermic reactions of the type A+B→C, in the presence of many (greater than 104) reacting particles. Two-body Lennard-Jones based potentials, Vij, have been utilized, in which the reaction takes place via an attractive potential VAB with a deep enough potential well. The other potentials VAC and VBC have deeper wells than VAB for creating a suitable situation for inducing exothermic reactions, while a high-energy plateau for VAC and VBC is used for simulating endothermic reactions. We have deployed 20000 to 100000 particles in a computational domain with an area of around 1 million Å2. These ensembles have all been integrated out to around the order of nanoseconds. We have examined the bimolecular reactions between two layers initially consisting of A particles lying atop B particles, equally divided in the total population. Reactions take place first along this boundary. There is a nonlinear threshold phenomenon in the exothermic reactions, which are greatly accelerated by the heat liberated from the neighboring reactions. In contrast, the endothermic reactions are more subdued, as there is no positive feedback 关键词: chemical reactions;chemically reactive flow;flow simulation;Lennard-Jones potential;molecular dynamics method;nonequilibrium flow;reaction kinetics theory;exothermic chemical reactions;endothermic chemical reactions;many particle systems;molecular dynamics simulation;kinetic rates;reactive flows;nonequilibrium flow;discrete-particle approach;chemical reactions modeling;two-body interparticle potentials;reaction kinetics theory;binary reactions;two-body Lennard-Jones potential;attractive potential;potential well;nonlinear threshold phenomenon;temperature dependence