Category
Applied
Description
Chemical reactors are vital in industrial operations; yet, experimental investigations of these processes are resource intensive. Computational fluid dynamics (CFD) simulations are beneficial over chemical simulation packages, because they capture spatiotemporal gradients of velocity, temperature, and species concentrations. However, due to the additional computational load of kinetics implementation into rigorous meshes, CFD simulations of chemical reactions can be prohibitively time consuming. Flow fields may reach quasi-steady state quickly, but convergence of kinetic solutions may take longer. This work aims to develop a punctuated equilibrium model (PEM) of a verified/validated free radical polymerization reaction in CFD to decrease solver runtime without sacrificing accuracy. We focus on a coarse continuous stirred tank reactor PEM to later be incorporated into a full-scale model. In PEMs, presumably irrelevant temporal changes in localized flow and turbulence are ignored. However, the model remains valid; everything needed to calculate polymer properties is still intact. Tests vary combinations of disabled features/equations including flow, turbulence, energy, and more. Accuracy is determined by percent error in polydispersity index (PDI) from the verified base case with all solution variables enabled. The most effective PEM case, with pressure-velocity coupling and turbulence disabled, has a solver rate 1.05x the base with PDI accuracy within 0.04% of the target. Though this speed increase is insignificant, the relative speed advantage of PEMs increases with cell count; implementation into larger models yields greater computational efficiency. This demonstrates the feasibility of CFD PEMs simulating chemical reactors, saving time and resources for reactor-scale simulations.
Developing a Polymerization Reactor Punctuated Equilibrium Model
Applied
Chemical reactors are vital in industrial operations; yet, experimental investigations of these processes are resource intensive. Computational fluid dynamics (CFD) simulations are beneficial over chemical simulation packages, because they capture spatiotemporal gradients of velocity, temperature, and species concentrations. However, due to the additional computational load of kinetics implementation into rigorous meshes, CFD simulations of chemical reactions can be prohibitively time consuming. Flow fields may reach quasi-steady state quickly, but convergence of kinetic solutions may take longer. This work aims to develop a punctuated equilibrium model (PEM) of a verified/validated free radical polymerization reaction in CFD to decrease solver runtime without sacrificing accuracy. We focus on a coarse continuous stirred tank reactor PEM to later be incorporated into a full-scale model. In PEMs, presumably irrelevant temporal changes in localized flow and turbulence are ignored. However, the model remains valid; everything needed to calculate polymer properties is still intact. Tests vary combinations of disabled features/equations including flow, turbulence, energy, and more. Accuracy is determined by percent error in polydispersity index (PDI) from the verified base case with all solution variables enabled. The most effective PEM case, with pressure-velocity coupling and turbulence disabled, has a solver rate 1.05x the base with PDI accuracy within 0.04% of the target. Though this speed increase is insignificant, the relative speed advantage of PEMs increases with cell count; implementation into larger models yields greater computational efficiency. This demonstrates the feasibility of CFD PEMs simulating chemical reactors, saving time and resources for reactor-scale simulations.
