Campus Units

Mechanical Engineering, Chemical and Biological Engineering, Ames Laboratory

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

9-19-2020

Journal or Book Title

Proceedings of the Combustion Institute

DOI

10.1016/j.proci.2020.07.075

Abstract

Two solution algorithms are developed for the conditional moment closure (CMC) using quadrature-based moment methods (QBMM). Their primary purpose is to eliminate the necessity of the additional grid for the conditioning variable (e.g., mixture fraction). As in almost every probability-density-function (PDF)-based description, the main technical hurdle is the solution of the molecular-mixing term. Here the focus is on solving this term coupled with chemistry, as opposed to spatial transport. In the first algorithm (referred to as SA-CMC), this is done by semi-analytically solving an equation for the deviation variable of the conditional scalar mean in terms of Jacobi polynomials. The mixture-fraction space is represented by the Gauss–Lobatto quadrature rule and a β-PDF. In the second algorithm (referred to as QBMM-CMC), a closed set of differential equations is written for the joint moments of a scalar and the mixture fraction, thereby eliminating the need to assume a form for the mixture-fraction PDF. Both solution algorithms are tested for multi-step H2 combustion, and the expected results are achieved with at most six quadrature nodes. Since in the proposed algorithms the scalar mean is ensured to be constant during molecular mixing, it is further concluded that the proposed algorithms are accurate, computationally cost-effective, and straightforward alternatives for traditional CMC solution methods.

Comments

This is a manuscript of an article published as Ilgun, A. D., A. Passalacqua, and R. O. Fox. "Application of quadrature-based moment methods to the conditional moment closure." Proceedings of the Combustion Institute (2020). DOI: 10.1016/j.proci.2020.07.075. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

The Combustion Institute

Language

en

File Format

application/pdf

Available for download on Monday, September 19, 2022

Published Version

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