Researcher:
Türkeri, Hasret

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PhD Student

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Hasret

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Türkeri

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Türkeri, Hasret

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2014 - 201922020 - 20211

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Researcher Of Publications: search.filters.isAuthorOfPublication.4d43da1a-2445-4b4d-8949-3857665ecd7f

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    A new robust consistent hybrid finite-volume/particle method for solving the PDF model equations of turbulent reactive flows
    (Pergamon-Elsevier Science Ltd, 2014) Department of Mechanical Engineering; Sheikhsarmast, Reza Mokhtarpoor; Türkeri, Hasret; Muradoğlu, Metin; PhD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 46561
    A new robust hybrid finite-volume (FV)/particle method is developed for solving joint probability density function (JPDF) model equations of statistically stationary turbulent reacting flows. The method is designed to remedy the deficiencies of the hybrid algorithm developed by Muradoglu et al. (1999, 2001). The density-based FV solver in the original hybrid algorithm has been found to be excessively dissipative and yet not very robust. To remedy these deficiencies, a pressure-based PISO algorithm in the open source FV package, OpenFOAM, is used to solve the Favre-averaged mean mass and momentum equations while a particle-based Monte Carlo algorithm is employed to solve the fluctuating velocity-turbulence frequency-compositions JPDF transport equation. The mean density is computed as a particle field and passed to the FV method. Thus the redundancy of the density fields in the original hybrid method is removed making the new hybrid algorithm more consistent at the numerical solution level. The new hybrid algorithm is first applied to simulate non-swirling cold and reacting bluff-body flows. The convergence of the method is demonstrated. In contrast with the original hybrid method, the new hybrid algorithm is very robust with respect to grid refinement and achieves grid convergence without any unphysical vortex shedding in the cold bluff-body flow case. In addition, the results are found to be in good agreement with the earlier PDF calculations and also with the available experimental data. Finally the new hybrid algorithm is successfully applied to simulate the more complicated Sydney swirling bluff-body flame 'SM1'. The method is also very robust for this difficult test case and the results are in good agreement with the available experimental data. In all the cases, the PISO-FV solver is found to be highly resilient to the noise in the mean density field extracted from the particles.
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    Large eddy simulation/probability density function modeling of turbulent swirling stratified flame series
    (Amer Inst Physics, 2021) Zhao, Xinyu; Department of Mechanical Engineering; N/A; Muradoğlu, Metin; Türkeri, Hasret; Faculty Member; PhD Student; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; 46561
    The large eddy simulation/probability density function (LES/PDF) method is applied to a turbulent swirling stratified flame series to systematically investigate its performance for accurate prediction of effects of stratification on turbulent flames under swirling conditions. The Cambridge/Sandia turbulent stratified flame series is selected as a target flame series. An augmented reduced mechanism is used for the methane/air combustion. The chemical calculations are accelerated by using the in situ adaptive tabulation method. The differential diffusion and heat loss from the bluff-body surface are taken into account in the simulations. The effect of stratification in fuel concentration is studied by increasing the stratification progressively from the pure premixed case to moderately and highly stratified cases. The performance of the LES/PDF modeling is evaluated by comparing the numerical results with the experimental data. The computed mean and rms of velocity, temperature, equivalence ratio, and mass fractions of species are found to be in good agreement with the measurements for all three conditions. Scatter plots and conditional means of mole fractions of species and temperature are presented and found to be in overall good consistency with those obtained from the experimental measurements. The recirculation zones are found to be about five times longer than those obtained under the non-swirling conditions. A low-equivalence-ratio high-temperature region near the bluff body is not captured in the computation, which is attributed to the insufficient entrainment of downstream mixtures into the recirculation zone. The parametric studies show that the differential diffusion has a minor effect on the mean and rms quantities, while the heat loss has a considerable effect on temperature and CO profiles close to the bluff body.
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    A LES/PDF simulator on block-structured meshes
    (Taylor & Francis Ltd, 2019) Pope, Stephen B.; N/A; Department of Mechanical Engineering; Türkeri, Hasret; Muradoğlu, Metin; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 46561
    A block-structured mesh large-eddy simulation (LES)/probability density function (PDF) simulator is developed within the OpenFOAM framework for computational modelling of complex turbulent reacting flows. The LES/PDF solver is a hybrid solution methodology consisting of (i) a finite-volume (FV) method for solving the filtered mass and momentum equations (LES solver), and (ii) a Lagrangian particle-based Monte Carlo algorithm (PDF solver) for solving the modelled transport equation of the filtered joint PDF of compositions. Both the LES and the PDF methods are developed and combined to form a hybrid LES/PDF simulator entirely within the OpenFOAM framework. The in situ adaptive tabulation method [S.B. Pope, Computationally efficient implementation of combustion chemistry using in situ adaptive tabulation, Combust. Theory Model. 1 (1997), pp. 41-63; L. Lu, S.R. Lantz, Z. Ren, and B.S. Pope, Computationally efficient implementation of combustion chemistry in parallel PDF calculations, J. Comput. Phys. 228 (2009), pp. 5490-5525] is incorporated into the new LES/PDF solver for efficient computations of combustion chemistry with detailed reaction kinetics. The method is designed to utilise a block-structured mesh and can readily be extended to unstructured grids. The three-stage velocity interpolation method of Zhang and Haworth [A general mass consistency algorithm for hybrid particle/finite-volume PDF methods, J. Comput. Phys. 194 (2004), pp. 156-193] is adapted to interpolate the LES velocity field onto particle locations accurately and to enforce the consistency between LES and PDF fields at the numerical solution level. The hybrid algorithm is fully parallelised using the conventional domain decomposition approach. A detailed examination of the effects of each stage and the overall performance of the velocity interpolation algorithm is performed. Accurate coupling of the LES and PDF solvers is demonstrated using the one-way coupling methodology. Then the fully two-way coupled LES/PDF solver is successfully applied to simulate the Sandia Flame-D, and a turbulent non-swirling premixed flame and a turbulent swirling stratified flame from the Cambridge turbulent stratified flame series [M.S. Sweeney, S. Hochgreb, M.J. Dunn, and R.S. Barlow, The structure of turbulent stratified and premixed methane/air flames I: Non-swirling flows, Combust. Flame 159 (2012), pp. 2896-2911; M.S. Sweeney, S. Hochgreb, M.J. Dunn, and R.S. Barlow, The structure of turbulent stratified and premixed methane/air flames II: Swirling flows, Combust. Flame 159 (2012), pp. 2912-2929]. It is found that the LES/PDF method is very robust and the results are in good agreement with the experimental data for both flames.