Assessment of a transient homogeneous reactor through in situ adaptive tabulation

TL;DR

This paper evaluates an in situ adaptive tabulation (ISAT) method for simulating chemically reacting flows in homogeneous reactors, demonstrating significant computational speedups with acceptable accuracy but high memory demands.

Contribution

It introduces an implementation of ISAT for homogeneous reactor models, analyzing its accuracy, efficiency, and memory usage with detailed reaction mechanisms.

Findings

Absolute global error less than 1% with ISAT.

Up to 80% reduction in computational time compared to direct integration.

Memory usage is excessively demanding with the current ISAT implementation.

Abstract

The development of computational models for the numerical simulation of chemically reacting flows operating in the turbulent regime requires the solution of partial differential equations that represent the balance of mass, linear momentum, chemical species, and energy. The chemical reactions of the model may involve detailed reaction mechanisms for the description of the physicochemical phenomena. One of the biggest challenges is the stiffness of the numerical simulation of these models and the nonlinear nature of species rate of reaction. This work presents a study of in situ adaptive tabulation (ISAT) technique, focusing on the accuracy, efficiency, and memory usage in the simulation of homogeneous stirred reactor models using simple and complex reaction mechanisms. The combustion of carbon monoxide with oxygen and methane with air mixtures are considered, using detailed reaction mechanisms with 4 and 53 species, 3 and 325 reactions, respectively. The results of these simulations indicate that the developed implementation of ISAT technique has a absolute global error smaller than 1 %. Moreover, ISAT technique provides gains, in terms of computational time, of up to 80% when compared with the direct integration of the full chemical kinetics. However, in terms of memory usage the present implementation of ISAT technique is found to be excessively demanding.