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A priori evaluation of the Double-conditioned Conditional Source-term Estimation model for high-pressure heptane turbulent combustion using DNS data obtained with one-step chemistry

Bushe, W. Kendal and Devaud, Cecile and Bellan, Josette (2020) A priori evaluation of the Double-conditioned Conditional Source-term Estimation model for high-pressure heptane turbulent combustion using DNS data obtained with one-step chemistry. Combustion and Flame, 217 . pp. 131-151. ISSN 0010-2180. https://resolver.caltech.edu/CaltechAUTHORS:20200420-153316450

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Abstract

An evaluation of the submodels constituting the Double-Conditioned Source-term Estimation (DCSE) method for utilization in Large Eddy Simulation (LES) is presented which makes use of a single realization of a turbulent high-pressure reactive-flow database obtained from Direct Numerical Simulation (DNS). A filtered and coarsened DNS (FCDNS) field is first created to mimic a real LES field, and the FCDNS values for thermodynamic variables (temperature, density and species mass fractions) are used as inputs to the DCSE model to predict the FCDNS reaction rates. It is found that there are significant errors in the predictions of the filtered reaction rate compared to the template. These errors are attributed to three important aspects of the model. First, the conditional-filtered values of the thermodynamic variables are found by an inversion of an integral equation, but this inversion requires the definition of spatial ensembles in which it must be performed; these ensembles are a subset of the entire spatial domain containing the LES volumes. A drastic reduction in the number of ensembles from the number of LES volumes (i.e. the largest possible number of such ensembles) deteriorates the model, whereas a further and smaller such reduction has a small effect. Second, the procedure for the integral inversion introduces problems related to the method selected to regularize the inversion. Third, by far the largest source of error was found to be due to the modelling of the joint probability density function of the conditioning variables: assuming a β-PDF for the marginal PDF of the reaction progress variable is shown to be a particularly poor choice, as is the assumption that the conditioning variables are statistically independent.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.combustflame.2020.03.015DOIArticle
ORCID:
AuthorORCID
Bellan, Josette0000-0001-9218-7017
Additional Information:© 2020 The Combustion Institute. Published by Elsevier Inc. Received 6 August 2019, Revised 23 September 2019, Accepted 15 March 2020, Available online 20 April 2020. The Department of Energy (DoE), Basic Energy Sciences (BES) supported Dr. Josette Bellan through Grant DE-SC0002679 at the California Institute of Technology as part of the program directed by Dr. Wade Sisk at DoE/BES. The computations were performed using resources at the University of Waterloo, Canada, and at the University of British Columbia, Canada.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0002679
Subject Keywords:High-pressure combustion; Modelling; DCSE; Inversion; PDF
Record Number:CaltechAUTHORS:20200420-153316450
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200420-153316450
Official Citation:W. Kendal Bushe, Cecile Devaud, Josette Bellan, A priori evaluation of the Double-conditioned Conditional Source-term Estimation model for high-pressure heptane turbulent combustion using DNS data obtained with one-step chemistry, Combustion and Flame, Volume 217, 2020, Pages 131-151, ISSN 0010-2180, https://doi.org/10.1016/j.combustflame.2020.03.015. (http://www.sciencedirect.com/science/article/pii/S0010218020301164)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102674
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:20 Apr 2020 23:12
Last Modified:20 Apr 2020 23:12

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