A Non-Isothermal Chemical Lattice Boltzmann Model Incorporating Thermal Reaction Kinetics and Enthalpy Changes

Abstract

Abstract:The lattice Boltzmann method is an efficient computational fluid dynamics technique that can accurately model a broad range of complex systems. As well as single-phase fluids, it can simulate thermohydrodynamic systems and passive scalar advection. In recent years, it also gained attention as a means of simulating chemical phenomena, as interest in self-organization processes increased. This paper will present a widely-used and versatile lattice Boltzmann model that can simultaneously incorporate fluid dynamics, heat transfer, buoyancy-driven convection, passive scalar advection, chemical reactions and enthalpy changes. All of these effects interact in a physically accurate framework that is simple to code and readily parallelizable. As well as a complete description of the model equations, several example systems will be presented in order to demonstrate the accuracy and versatility of the method. New simulations, which analyzed the effect of a reversible reaction on the transport properties of a convecting fluid, will also be described in detail. This extra chemical degree of freedom was utilized by the system to augment its net heat flux. The numerical method outlined in this paper can be readily deployed for a vast range of complex flow problems, spanning a variety of scientific disciplines.

Computation by Convective Logic Gates and Thermal Communication

“…This method numerically solves the non-equilibrium Boltzmann equation for an incompressible fluid. The momentum equation and the advection-diffusion equation above can then be derived from the Lattice Boltzmann equation S. Bartlett, 2017;Dixit and Babu, 2006;He et al, 1998;Liu et al, 2010;Pareschi et al, 2016;Peng et al, 2003;Succi, 2001. The method solves for the instantaneous motion of the fluid and thus can illuminate unsteady and steady state behavior.…”

“…Fully turbulent flows would require large temperature differences or exotic fluid properties, and would also exhibit disruptive instabilities. The grid size used was 240x360 for each convective gate, with a lattice relaxation time of τ ν = 0.7 (see S. Bartlett, 2017;Peng et al, 2003, for further details on this method).…”

“…These do not require obstacles to exhibit bistability, and also use no-slip vertical walls instead of periodic boundary conditions, thus simplifying the design. We explore these systems using high accuracy Lattice Boltzmann models, which have been widely used for thermal fluid simulations for several decades (S. Bartlett, 2017;Dixit & Babu, 2006;He et al, 1998;Liu et al, 2010;Pareschi et al, 2016;Peng et al, 2003;Succi, 2001). The results of these simulations can pave the way for implementation in real world settings.…”

Convective flow in the presence of a small obstacle: Symmetry breaking, attractors, hysteresis, and information

“…The method numerically solves the nonequilibrium Boltzmann equation for an incompressible fluid. The momentum equation and the advection-diffusion equation shown above can then be derived from the lattice Boltzmann equation [48][49][50][51][52]. The Prandtl number was fixed at Pr = 1, and the numerical domain consisted of 512 × 256 grid cells.…”

Boolean logic by convective obstacle flows

“…The fluid dynamics and heat transport are simulated using a thermal lattice Boltzmann model, which has been rigorously analysed and tested across a broad range of thermal flow problems over several decades [60][61][62][63][64][65][66]. Momentum extraction is implemented using a simple body force method.…”