Title: Adjoint-based reconstruction of an entropy source by discrete temperature measurements

Authors: M. Lemke; J. Schulze; J. Sesterhenn

Addresses: Department of Numerical Fluid Dynamics, Institute of Fluid Dynamics and Technical Acoustics, Technical University of Berlin, Müller-Breslau-Straße 8, 10623, Germany ' Department of Numerical Fluid Dynamics, Institute of Fluid Dynamics and Technical Acoustics, Technical University of Berlin, Müller-Breslau-Straße 8, 10623, Germany ' Department of Numerical Fluid Dynamics, Institute of Fluid Dynamics and Technical Acoustics, Technical University of Berlin, Müller-Breslau-Straße 8, 10623, Germany

Abstract: The heat release rate is a significant quantity of lean premixed flames in technical flows. The heat release is commonly determined by OH* chemiluminescence measurements which are not fully reliable for turbulent flames owing to a superposition of desired emissions and broadband noise. The present study applies an adjoint-based data assimilation technique in order to reconstruct the heat release rate of a flame from pointwise temperature measurements. As a simplified test case, the method is applied to a two-dimensional channel flow and the combustion process is modelled by an artificial entropy source distributed in space and time.

Keywords: inverse problems; numerical simulation; nonlinear optimisation; continuous adjoint methods; data assimilation; computational science; adjoint-based reconstruction; entropy source; discrete temperature measurements; heat release rate; lean premixed flames; technical flows; 2D channel flow; combustion process; modelling.

DOI: 10.1504/IJCSE.2014.064537

International Journal of Computational Science and Engineering, 2014 Vol.9 No.5/6, pp.526 - 537

Received: 16 Jan 2012
Accepted: 21 Sep 2012

Published online: 22 Sep 2014 *

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