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Dr. Somesh Roy
Department of Mechanical Engineering, Marquette university, Milwaukee, WI 53233, USA

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Research Keywords & Expertise

0 Combustion modeling
0 Soot modeling
0 Radiative heat transfer in combustion
0 Interaction of turbulence, chemistry, soot and radiation in combustion
0 Multiphase combustion

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Radiative heat transfer in combustion
Soot modeling

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Preprint content
Published: 16 July 2021
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ACS Style

Tamanna Tasnim; John. A Moore; Somesh Roy. Cohesive Zone Modeling of Interfaces Under High Impact Velocity Collisions. 2021, 1 .

AMA Style

Tamanna Tasnim, John. A Moore, Somesh Roy. Cohesive Zone Modeling of Interfaces Under High Impact Velocity Collisions. . 2021; ():1.

Chicago/Turabian Style

Tamanna Tasnim; John. A Moore; Somesh Roy. 2021. "Cohesive Zone Modeling of Interfaces Under High Impact Velocity Collisions." , no. : 1.

Journal article
Published: 05 May 2021 in Carbon
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Reactive molecular dynamics (MD) simulations are employed to investigate the coalescence of incipient soot clusters. Initially, one thousand acetylene molecules collide and react with each other, allowing bond breakage and new bond formation upon collision, leading to various species (e.g., linear hydrocarbons, branched polyaromatic hydrocarbons) up to the formation of nascent soot clusters with diameter of up to 3.5 nm. The structure and composition of the formed soot clusters are quantified by the packing density and carbon-to-hydrogen (C/H) ratio, respectively, during nucleation and up to the formation of large nascent soot nanoparticles. Then, the nucleated incipient soot clusters are isolated from the surrounding reactive species and are allowed to coalesce with each other isothermally to investigate soot coalescence. The coalescence between incipient soot clusters of different sizes is elucidated at various process temperatures, ranging from 800 to 1800 K. The characteristic coalescence time of nascent soot is quantified by tracking the evolution of the particle surface area, for the first time. Soot clusters consisting of up to 760 atoms coalesce instantly (within 0.1 ns), especially at relatively low temperatures (i.e., 800–1000 K). At higher temperatures (1200–1600 K), incipient soot clusters are less prone to coalescence due to the larger fraction of constituent aromatic rings leading to more rigid particles. Large clusters consisting of more than 1300 atoms do not coalesce within the time scales investigated here (i.e., up to 5 ns). The employed reactive MD approach gives significant insight into fundamental soot formation and growth mechanisms, which are typically treated semi-empirically, facilitating a better understanding and more efficient control of soot in combustion processes.

ACS Style

Akaash Sharma; Khaled Mosharraf Mukut; Somesh P. Roy; Eirini Goudeli. The coalescence of incipient soot clusters. Carbon 2021, 180, 215 -225.

AMA Style

Akaash Sharma, Khaled Mosharraf Mukut, Somesh P. Roy, Eirini Goudeli. The coalescence of incipient soot clusters. Carbon. 2021; 180 ():215-225.

Chicago/Turabian Style

Akaash Sharma; Khaled Mosharraf Mukut; Somesh P. Roy; Eirini Goudeli. 2021. "The coalescence of incipient soot clusters." Carbon 180, no. : 215-225.

Journal article
Published: 15 October 2020 in International Journal of Heat and Mass Transfer
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This study presents a new methodology to solve thermal radiation in participating gases, the spectrally reduced integration (SRI), which employs a non-uniform spectral discretization to considerably reduce the computational cost of the line-by-line (LBL) solution while still maintaining good levels of accuracy. This non-uniform spectral mesh is generated from discretization schemes based on the spectral contributions of the bands, which apply less or more refined spectral resolution depending on the importance of the bands to the radiative transfer. Based on this methodology, several schemes were initially proposed and evaluated for a homogeneous H2O-CO2 mixture test case. Results showed that the most refined schemes were able to generate highly accurate results three to five times faster than the reference LBL solution, while the coarser schemes were still interesting alternatives for faster but still reliable calculations. In fact, a compromise between the accuracy of the SRI solution and the total number of spectral intervals was observed in all the tested schemes. The SRI method also presented similarly promising results when solving non-homogeneous test cases. Finally, the present study also develops two alternatives to address the need of a priori evaluation of the spectral contributions of the bands when using the discretization schemes. These two methodologies produced surprisingly accurate solutions of the non-homogeneous test cases, each with its own advantages and disadvantages, and could be applied together to further simplify the use of the SRI in highly accurate coupled combustion problems.

ACS Style

Felipe R. Coelho; Aline Ziemniczak; Somesh P. Roy; Francis H.R. França. A new line-by-line methodology based on the spectral contributions of the bands. International Journal of Heat and Mass Transfer 2020, 164, 120423 .

AMA Style

Felipe R. Coelho, Aline Ziemniczak, Somesh P. Roy, Francis H.R. França. A new line-by-line methodology based on the spectral contributions of the bands. International Journal of Heat and Mass Transfer. 2020; 164 ():120423.

Chicago/Turabian Style

Felipe R. Coelho; Aline Ziemniczak; Somesh P. Roy; Francis H.R. França. 2020. "A new line-by-line methodology based on the spectral contributions of the bands." International Journal of Heat and Mass Transfer 164, no. : 120423.

Research article
Published: 19 April 2020 in Computer Applications in Engineering Education
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Providing engineering undergraduate students opportunities to connect real‐world applications with a theory is key to preparing them for the workforce; however, this task often requires a balancing act between meeting course objectives in content‐heavy core engineering undergraduate courses and providing experiences that connect real‐world applications with theory. This study seeks to address this problem through the integration of online discussion prompts to promote a connection to real‐world practical applications. The study included undergraduate students enrolled in three engineering core courses. The hypothesis was that participation in online discussions (using prompts) would lead to (a) an increase in student empowerment towards self‐regulated learning and (b) enhanced student engagement and perception of participating in online discussions. Students participated in eight online discussions and were evaluated using pre‐ and post‐assessments. Findings show students across disciplines liked online discussions because they allowed enough time to develop thoughts and promote critical thinking through extending class topics, which increased the control of their own learning. In addition, students were more active in the course activities and offered useful feedback and reflection, which enhanced student engagement. Such feedback included ideas to improve the online discussion, for example, the need for clearer instructions and instructor feedback, better scheduling of due dates, and more engaging discussion prompt. In summary, integrating online discussions into core engineering courses, without sacrificing class content, can indeed have positive implications for self‐regulated learning and higher student engagement.

ACS Style

Lisa Bosman; Somesh Roy; Walter McDonald; Cristinel Ababei. Using online discussions to connect theory and practice in core engineering undergraduate courses. Computer Applications in Engineering Education 2020, 28, 675 -691.

AMA Style

Lisa Bosman, Somesh Roy, Walter McDonald, Cristinel Ababei. Using online discussions to connect theory and practice in core engineering undergraduate courses. Computer Applications in Engineering Education. 2020; 28 (3):675-691.

Chicago/Turabian Style

Lisa Bosman; Somesh Roy; Walter McDonald; Cristinel Ababei. 2020. "Using online discussions to connect theory and practice in core engineering undergraduate courses." Computer Applications in Engineering Education 28, no. 3: 675-691.

Journal article
Published: 12 February 2020 in Combustion Theory and Modelling
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ACS Style

Khaled Mosharraf Mukut; Somesh P. Roy. Effect of O2 concentration in ambient mixture and multiphase radiation on pollutant formation in ECN spray-A. Combustion Theory and Modelling 2020, 24, 549 -572.

AMA Style

Khaled Mosharraf Mukut, Somesh P. Roy. Effect of O2 concentration in ambient mixture and multiphase radiation on pollutant formation in ECN spray-A. Combustion Theory and Modelling. 2020; 24 (3):549-572.

Chicago/Turabian Style

Khaled Mosharraf Mukut; Somesh P. Roy. 2020. "Effect of O2 concentration in ambient mixture and multiphase radiation on pollutant formation in ECN spray-A." Combustion Theory and Modelling 24, no. 3: 549-572.

Journal article
Published: 13 January 2020 in Combustion and Flame
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Turbulent pool fires have been studied as a canonical configuration in fire science with wide interest. A numerical study of a small-scale turbulent heptane pool fire is conducted in the present study to understand the interactions and coupling among turbulence, chemistry, soot, and radiation in pool fires. A Monte Carlo ray tracing based radiation solver, with line-by-line spectral models for five gaseous species and soot, is coupled with a fireFOAM-based reacting flow solver to describe the dynamics of the target fire. A 33-species skeletal mechanism is employed to describe the finite-rate chemistry. A two-equation soot model with C2H2 based inception model is incorporated to describe soot dynamics. Turbulence is resolved by the computational grid to avoid the uncertainties in modeling the sub-grid scale stress and turbulence-chemistry-radiation interactions. The computed radiative heat fluxes are directly compared with experimental signals and good agreement is observed. Rarely compared in the literature, the line-of-sight spectral distribution of the emissive power is computed and compared with experimental measurements with excellent match in the 4300 nm CO2-dominant emissive peak. A secondary emissive peak near 3300 nm is absent from the numerical results, which can be attributed to experimental uncertainties and/or insufficient representation of the C-H stretching bonds in the radiation spectral model. The instantaneous flame structures show the presence of abundant hydrocarbon molecules as fuel pyrolysis products. A detailed examination of the chemical and radiative source terms reveals the disproportionate relation between these two source terms, especially when soot is present. Soot radiation is largely optically thin while gas radiation is much thicker in optical depth, as a result of the spatial structures of the flame and the non-grey interactions between gas and soot. With the abundant information provided by the detailed simulation in this study, models for turbulence-chemistry-radiation interactions will be derived in future work.

ACS Style

Bifen Wu; Somesh Roy; Xinyu Zhao. Detailed modeling of a small-scale turbulent pool fire. Combustion and Flame 2020, 214, 224 -237.

AMA Style

Bifen Wu, Somesh Roy, Xinyu Zhao. Detailed modeling of a small-scale turbulent pool fire. Combustion and Flame. 2020; 214 ():224-237.

Chicago/Turabian Style

Bifen Wu; Somesh Roy; Xinyu Zhao. 2020. "Detailed modeling of a small-scale turbulent pool fire." Combustion and Flame 214, no. : 224-237.

Journal article
Published: 13 November 2019 in Journal of Quantitative Spectroscopy and Radiative Transfer
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The Monte Carlo (MC) method is the most accurate method for resolving radiative heat transfer in participating media. However, it is also computationally prohibitive in large-scale simulations. To alleviate this, this study proposes a quasi-Monte Carlo (QMC) method for thermal radiation in participating media with a focus on combustion-related problems. The QMC method employs low-discrepancy sequences (LDS) in place of the traditional random numbers. Three different low-discrepancy sequences – Sobol, Halton, and Niederreiter – were examined as part of this work. The developed QMC method was first validated against analytical solutions of radiative heat transfer in several one-dimensional configurations. Then it was extended to three-dimensional practical combustion configurations. The results from QMC and traditional Monte Carlo are compared against benchmark solutions for each cases. It is shown that the error of the predicted radiation field from QMC is lower than an equivalent MC simulation. The computational cost of QMC was also found lower than MC due to the avoidance of requirement of several statistical runs for traditional Monte Carlo methods alongside achieving the reduction in error. In conclusion, significant improvements in computational costs and accuracy seen in the QMC method makes it an attractive alternative to traditional Monte Carlo methods in high-fidelity simulations.

ACS Style

Joseph Farmer; Somesh Roy. A quasi-Monte Carlo solver for thermal radiation in participating media. Journal of Quantitative Spectroscopy and Radiative Transfer 2019, 242, 106753 .

AMA Style

Joseph Farmer, Somesh Roy. A quasi-Monte Carlo solver for thermal radiation in participating media. Journal of Quantitative Spectroscopy and Radiative Transfer. 2019; 242 ():106753.

Chicago/Turabian Style

Joseph Farmer; Somesh Roy. 2019. "A quasi-Monte Carlo solver for thermal radiation in participating media." Journal of Quantitative Spectroscopy and Radiative Transfer 242, no. : 106753.

Journal article
Published: 08 December 2018 in Combustion and Flame
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In recent years, the importance of radiative heat transfer in combustion has been increasingly recognized. Detailed models have become available that accurately represent the complex spectral radiative properties of reacting gas mixtures and soot particles, and new methods have been developed to solve the radiative transfer equation (RTE). At the same time, the trends toward higher operating pressures and higher levels of exhaust-gas recirculation in compression-ignition engines, together with the demand for higher quantitative accuracy from in-cylinder CFD models, has led to renewed interest in radiative transfer in engines. Here an in-depth investigation of radiative heat transfer is performed for a heavy-duty diesel truck engine over a range of operating conditions. Results from 10 different combinations of turbulent combustion models, spectral radiation property models, and RTE solvers are compared to provide insight into the global influences of radiation on energy redistribution in the combustion chamber, heat losses, and engine-out pollutant emissions (NO and soot). Also, the relative importance of the individual contributions of molecular gas versus soot radiation, the spectral model, the RTE solver, and unresolved turbulent fluctuations in composition and temperature (turbulence–radiation interactions – TRI) are investigated. Local instantaneous temperatures change by as much as 100 K with consideration of radiation, but the global influences of radiation on heat losses and engine-out emissions are relatively small (in the 5–10% range). Molecular gas radiation dominates over soot radiation, consideration of spectral properties is essential for accurate predictions of reabsorption, a simple RTE solver (a first-order spherical harmonics – P1 – method) is sufficient for the conditions investigated, and TRI effects are small (less than 10%). While the global influences of radiation are relatively small, it is nevertheless desirable to explicitly account for radiation in in-cylinder CFD. To that end, a simplified CFD radiation model has been proposed, based on the findings reported here.

ACS Style

Chandan Paul; Sebastian Ferreyro Fernandez; Daniel C. Haworth; Somesh Roy; Michael F. Modest. A detailed modeling study of radiative heat transfer in a heavy-duty diesel engine. Combustion and Flame 2018, 200, 325 -341.

AMA Style

Chandan Paul, Sebastian Ferreyro Fernandez, Daniel C. Haworth, Somesh Roy, Michael F. Modest. A detailed modeling study of radiative heat transfer in a heavy-duty diesel engine. Combustion and Flame. 2018; 200 ():325-341.

Chicago/Turabian Style

Chandan Paul; Sebastian Ferreyro Fernandez; Daniel C. Haworth; Somesh Roy; Michael F. Modest. 2018. "A detailed modeling study of radiative heat transfer in a heavy-duty diesel engine." Combustion and Flame 200, no. : 325-341.

Journal article
Published: 01 April 2018 in Combustion and Flame
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A transported probability density function (PDF) method and a photon Monte Carlo/line-by-line (PMC/LBL) spectral model are exercised to generate physical insight into soot processes and spectral radiation characteristics in transient high-pressure turbulent n-dodecane spray flames, under conditions that are relevant for compression-ignition piston engines. PDF model results are compared with experimental measurements and with results from a locally well-stirred reactor (WSR) model that neglects unresolved turbulent fluctuations in composition and temperature. Computed total soot mass and soot spatial distributions are highly sensitive to the modeling of unresolved turbulent fluctuations. To achieve reasonable agreement between model and experiment and to capture the highly intermittent nature of soot in the turbulent flame, it is necessary to accurately represent mixing and the low diffusivity of soot particles. This is accomplished in the PDF framework using a mixing model that enforces locality in the gas-phase composition space, while not mixing the transported soot variables. The results suggest that mixing is at least as important as kinetics in controlling soot formation and evolution in high-pressure turbulent flames. Regarding radiation, radiant fractions and global influences of radiation in these flames are relatively small. Nevertheless, an examination of spectral radiative heat transfer provides valuable insight into the nature and modeling of radiation in high-pressure turbulent combustion systems. There are complex spectral interactions that are revealed using PMC/LBL. CO2 dominates the total radiative emission and reabsorption, but most of the emitted CO2 radiation is reabsorbed before reaching the walls. On the other hand, most of the emitted soot radiation reaches the walls, but soot radiation is a small contribution overall; H2O dominates the radiation that reaches the walls. Global turbulence–radiation interactions (TRI) effects are small, but radiative emission from soot increases by approximately a factor two when TRI are considered. Radiative transfer contributes both to energy redistribution in the vessel and to wall heat losses. The results suggest that a simple model that considers soot radiation and the principal CO2 and H2O spectral bands might be sufficient to capture the key influences of radiation in engine CFD. It is expected that these findings will contribute to the development of truly predictive CFD models for engines and other high-pressure turbulent combustion systems.

ACS Style

Sebastian Ferreyro Fernandez; C. Paul; A. Sircar; A. Imren; D.C. Haworth; S. Roy; M.F. Modest. Soot and spectral radiation modeling for high-pressure turbulent spray flames. Combustion and Flame 2018, 190, 402 -415.

AMA Style

Sebastian Ferreyro Fernandez, C. Paul, A. Sircar, A. Imren, D.C. Haworth, S. Roy, M.F. Modest. Soot and spectral radiation modeling for high-pressure turbulent spray flames. Combustion and Flame. 2018; 190 ():402-415.

Chicago/Turabian Style

Sebastian Ferreyro Fernandez; C. Paul; A. Sircar; A. Imren; D.C. Haworth; S. Roy; M.F. Modest. 2018. "Soot and spectral radiation modeling for high-pressure turbulent spray flames." Combustion and Flame 190, no. : 402-415.

Journal article
Published: 12 December 2017 in Journal of Engineering for Gas Turbines and Power
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Radiative heat transfer is studied numerically for reacting swirling flow in an industrial gas turbine burner operating at a pressure of 15 bar. The reacting field characteristics are computed by Reynolds-averaged Navier–Stokes (RANS) equations using the k-ϵ model with the partially stirred reactor (PaSR) combustion model. The GRI-Mech 2.11 mechanism, which includes nitrogen chemistry, is used to demonstrate the ability of reducing NOx emissions of the combustion system. A photon Monte Carlo (PMC) method coupled with a line-by-line (LBL) spectral model is employed to accurately account for the radiation effects. Optically thin (OT) and PMC–gray models are also employed to show the differences between the simplest radiative calculation models and the most accurate radiative calculation model, i.e., PMC–LBL, for the gas turbine burner. It was found that radiation does not significantly alter the temperature level as well as CO2 and H2O concentrations. However, it has significant impacts on the NOx levels at downstream locations.

ACS Style

Tao Ren; Michael F. Modest; Somesh Roy. Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber. Journal of Engineering for Gas Turbines and Power 2017, 140, 051503 .

AMA Style

Tao Ren, Michael F. Modest, Somesh Roy. Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber. Journal of Engineering for Gas Turbines and Power. 2017; 140 (5):051503.

Chicago/Turabian Style

Tao Ren; Michael F. Modest; Somesh Roy. 2017. "Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber." Journal of Engineering for Gas Turbines and Power 140, no. 5: 051503.

Journal article
Published: 01 December 2017 in International Journal of Heat and Mass Transfer
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ACS Style

Somesh Roy; Jian Cai; Michael F. Modest. Development of a multiphase photon Monte Carlo method for spray combustion and its application in high-pressure conditions. International Journal of Heat and Mass Transfer 2017, 115, 453 -466.

AMA Style

Somesh Roy, Jian Cai, Michael F. Modest. Development of a multiphase photon Monte Carlo method for spray combustion and its application in high-pressure conditions. International Journal of Heat and Mass Transfer. 2017; 115 ():453-466.

Chicago/Turabian Style

Somesh Roy; Jian Cai; Michael F. Modest. 2017. "Development of a multiphase photon Monte Carlo method for spray combustion and its application in high-pressure conditions." International Journal of Heat and Mass Transfer 115, no. : 453-466.

Journal article
Published: 01 August 2017 in Journal of Quantitative Spectroscopy and Radiative Transfer
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ACS Style

Bifen Wu; Somesh Roy; Xinyu Zhao; Michael F. Modest. Effect of multiphase radiation on coal combustion in a pulverized coal jet flame. Journal of Quantitative Spectroscopy and Radiative Transfer 2017, 197, 154 -165.

AMA Style

Bifen Wu, Somesh Roy, Xinyu Zhao, Michael F. Modest. Effect of multiphase radiation on coal combustion in a pulverized coal jet flame. Journal of Quantitative Spectroscopy and Radiative Transfer. 2017; 197 ():154-165.

Chicago/Turabian Style

Bifen Wu; Somesh Roy; Xinyu Zhao; Michael F. Modest. 2017. "Effect of multiphase radiation on coal combustion in a pulverized coal jet flame." Journal of Quantitative Spectroscopy and Radiative Transfer 197, no. : 154-165.

Conference paper
Published: 09 July 2017 in Volume 1: Aerospace Heat Transfer; Computational Heat Transfer; Education; Environmental Heat Transfer; Fire and Combustion Systems; Gas Turbine Heat Transfer; Heat Transfer in Electronic Equipment; Heat Transfer in Energy Systems
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Radiative heat transfer is studied numerically for reacting swirling flow in an industrial gas turbine burner operating at a pressure of 15 bar. The reacting field characteristics are computed by Reynolds-averaged Navier-Stokes (RANS) equations using the k-ε model with the partially stirred reactor (PaSR) combustion model. The GRI-Mech 2.11 mechanism, which includes nitrogen chemistry, is used to demonstrate the the ability of reducing NOx emissions of the combustion system. A Photon Monte Carlo (PMC) method coupled with a line-by-line spectral model is employed to accurately account for the radiation effects. CO2, H2O and CO are assumed to be the only radiatively participating species and wall radiation is considered as well. Optically thin and PMC-gray models are also employed to show the differences between the simplest radiative calculation models and the most accurate radiative calculation model, i.e., PMC-LBL, for the gas turbine burner. It was found that radiation does not significantly alter the temperature level as well as CO2 and H2O concentrations. However, it has significant impacts on the NOx levels at downstream locations.

ACS Style

Tao Ren; Michael F. Modest; Somesh Roy. Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber. Volume 1: Aerospace Heat Transfer; Computational Heat Transfer; Education; Environmental Heat Transfer; Fire and Combustion Systems; Gas Turbine Heat Transfer; Heat Transfer in Electronic Equipment; Heat Transfer in Energy Systems 2017, 1 .

AMA Style

Tao Ren, Michael F. Modest, Somesh Roy. Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber. Volume 1: Aerospace Heat Transfer; Computational Heat Transfer; Education; Environmental Heat Transfer; Fire and Combustion Systems; Gas Turbine Heat Transfer; Heat Transfer in Electronic Equipment; Heat Transfer in Energy Systems. 2017; ():1.

Chicago/Turabian Style

Tao Ren; Michael F. Modest; Somesh Roy. 2017. "Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber." Volume 1: Aerospace Heat Transfer; Computational Heat Transfer; Education; Environmental Heat Transfer; Fire and Combustion Systems; Gas Turbine Heat Transfer; Heat Transfer in Electronic Equipment; Heat Transfer in Energy Systems , no. : 1.

Conference paper
Published: 01 January 2017 in Proceeding of Proceedings of CHT-17 ICHMT International Symposium on Advances in Computational Heat Transfer May 28-June 1, 2017, Napoli, Italy
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ACS Style

Wenjun Ge; Tao Ren; Michael F. Modest; Somesh P. Roy; Daniel C. Haworth. APPLICATION OF HIGH-ORDER SPHERICAL HARMONICS METHODS FOR RADIATIVE TRANSFER IN SIMULATION OF A TURBULENT JET FLAME. Proceeding of Proceedings of CHT-17 ICHMT International Symposium on Advances in Computational Heat Transfer May 28-June 1, 2017, Napoli, Italy 2017, 1 .

AMA Style

Wenjun Ge, Tao Ren, Michael F. Modest, Somesh P. Roy, Daniel C. Haworth. APPLICATION OF HIGH-ORDER SPHERICAL HARMONICS METHODS FOR RADIATIVE TRANSFER IN SIMULATION OF A TURBULENT JET FLAME. Proceeding of Proceedings of CHT-17 ICHMT International Symposium on Advances in Computational Heat Transfer May 28-June 1, 2017, Napoli, Italy. 2017; ():1.

Chicago/Turabian Style

Wenjun Ge; Tao Ren; Michael F. Modest; Somesh P. Roy; Daniel C. Haworth. 2017. "APPLICATION OF HIGH-ORDER SPHERICAL HARMONICS METHODS FOR RADIATIVE TRANSFER IN SIMULATION OF A TURBULENT JET FLAME." Proceeding of Proceedings of CHT-17 ICHMT International Symposium on Advances in Computational Heat Transfer May 28-June 1, 2017, Napoli, Italy , no. : 1.

Journal article
Published: 01 October 2016 in Journal of Quantitative Spectroscopy and Radiative Transfer
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ACS Style

Jian Cai; Somesh Roy; Michael F. Modest. A comparison of specularly reflective boundary conditions and rotationally invariant formulations for Discrete Ordinate Methods in axisymmetric geometries. Journal of Quantitative Spectroscopy and Radiative Transfer 2016, 182, 75 -86.

AMA Style

Jian Cai, Somesh Roy, Michael F. Modest. A comparison of specularly reflective boundary conditions and rotationally invariant formulations for Discrete Ordinate Methods in axisymmetric geometries. Journal of Quantitative Spectroscopy and Radiative Transfer. 2016; 182 ():75-86.

Chicago/Turabian Style

Jian Cai; Somesh Roy; Michael F. Modest. 2016. "A comparison of specularly reflective boundary conditions and rotationally invariant formulations for Discrete Ordinate Methods in axisymmetric geometries." Journal of Quantitative Spectroscopy and Radiative Transfer 182, no. : 75-86.

Journal article
Published: 01 March 2016 in Journal of Quantitative Spectroscopy and Radiative Transfer
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ACS Style

Wenjun Ge; Michael F. Modest; Somesh Roy. Development of high-order P models for radiative heat transfer in special geometries and boundary conditions. Journal of Quantitative Spectroscopy and Radiative Transfer 2016, 172, 98 -109.

AMA Style

Wenjun Ge, Michael F. Modest, Somesh Roy. Development of high-order P models for radiative heat transfer in special geometries and boundary conditions. Journal of Quantitative Spectroscopy and Radiative Transfer. 2016; 172 ():98-109.

Chicago/Turabian Style

Wenjun Ge; Michael F. Modest; Somesh Roy. 2016. "Development of high-order P models for radiative heat transfer in special geometries and boundary conditions." Journal of Quantitative Spectroscopy and Radiative Transfer 172, no. : 98-109.

Articles
Published: 24 February 2016 in Combustion Science and Technology
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This research is part of an ongoing assessment to identify the most promising soot models for applications to laboratory turbulent flames, and ultimately to practical combustion systems. To that end, it is of interest to compare soot model simulation results with experiments over a broad range of conditions. Here five steady, one-dimensional, laminar, premixed ethylene flames have been targeted that cover a range of C/O ratios (0.68 to 0.88), pressures (1 atm to 10 bar), and peak soot levels (0.03 to 3.2 ppm). Seven different chemical mechanisms have been considered. For each mechanism, results from several soot model variants are compared. Two different approaches for soot aerosol dynamics are used: a discrete sectional method (DSM), and a method of moments with interpolative closure (MOMIC). DSM and MOMIC results are also compared with those from a widely used semi-empirical two-equation soot model. The main figure-of-merit is the ratio of computed-to-measured peak soot volume fraction. The computed soot volume fraction is most sensitive to variations in the surface chemistry scheme. Sensitivities to variations in model configurations are reduced at high pressure. The DSM-based models yield slightly lower soot volume fraction and slightly larger particle size compared to the corresponding MOMIC-based models. A modified semi-empirical two-equation model produced a good match to experiment for all five flames. Particle sizes and number densities from the models are discussed for a low-sooting flame where such data are available. The DSM-based models produce bimodal particle size distributions that are qualitatively consistent with those observed experimentally. The best results overall are obtained using an underlying chemical mechanism that incorporates recent understanding of polycyclic aromatic hydrocarbons kinetics. There is no clear advantage of DSM over MOMIC in predicting global quantities, such as soot volume fraction, particle number density, and average particle size, while the computational cost of DSM is significantly higher than that of MOMIC.

ACS Style

Somesh P. Roy; Daniel C. Haworth. A Systematic Comparison of Detailed Soot Models and Gas-Phase Chemical Mechanisms in Laminar Premixed Flames. Combustion Science and Technology 2016, 188, 1021 -1053.

AMA Style

Somesh P. Roy, Daniel C. Haworth. A Systematic Comparison of Detailed Soot Models and Gas-Phase Chemical Mechanisms in Laminar Premixed Flames. Combustion Science and Technology. 2016; 188 (7):1021-1053.

Chicago/Turabian Style

Somesh P. Roy; Daniel C. Haworth. 2016. "A Systematic Comparison of Detailed Soot Models and Gas-Phase Chemical Mechanisms in Laminar Premixed Flames." Combustion Science and Technology 188, no. 7: 1021-1053.

Journal article
Published: 17 August 2015 in Combustion Theory and Modelling
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A two-dimensional simulation of a non-premixed ethylene–air flame was conducted by employing a detailed gas-phase reaction mechanism considering polycyclic aromatic hydrocarbons, an aerosol-dynamics-based soot model using a method of moments with interpolative closure, and a grey gas and soot radiation model using the discrete transfer method. Interaction of the sooting flame with a prescribed decaying random velocity field was investigated, with a primary interest in the effects of velocity fluctuations on the flame structure and the associated soot formation process for a fuel-strip configuration and a composition with mature soot growth. The temporally evolving simulation revealed a multi-layered soot formation process within the flame, at a level of detail not properly described by previous studies based on simplified soot models utilizing acetylene or naphthalene precursors for initial soot inception. The overall effect of the flame topology on the soot formation was found to be consistent with previous experimental studies, while a unique behaviour of localised strong oxidation was also noted. The imposed velocity fluctuations led to an increase of the scalar dissipation rate in the sooting zone, causing a net suppression in the soot production rate. Considering the complex structure of the soot formation layer, the effects of the imposed fluctuations vary depending on the individual soot reactions. For the conditions under study, the soot oxidation reaction was identified as the most sensitive to the fluctuations and was mainly responsible for the local suppression of the net soot production.

ACS Style

Paul G. Arias; Vivien R. Lecoustre; Somesh Roy; Zhaoyu Luo; Daniel C. Haworth; Tianfeng Lu; Arnaud Trouvé; Hong G. Im. Dynamics of flow–soot interaction in wrinkled non-premixed ethylene–air flames. Combustion Theory and Modelling 2015, 19, 1 -19.

AMA Style

Paul G. Arias, Vivien R. Lecoustre, Somesh Roy, Zhaoyu Luo, Daniel C. Haworth, Tianfeng Lu, Arnaud Trouvé, Hong G. Im. Dynamics of flow–soot interaction in wrinkled non-premixed ethylene–air flames. Combustion Theory and Modelling. 2015; 19 (5):1-19.

Chicago/Turabian Style

Paul G. Arias; Vivien R. Lecoustre; Somesh Roy; Zhaoyu Luo; Daniel C. Haworth; Tianfeng Lu; Arnaud Trouvé; Hong G. Im. 2015. "Dynamics of flow–soot interaction in wrinkled non-premixed ethylene–air flames." Combustion Theory and Modelling 19, no. 5: 1-19.

Journal article
Published: 01 May 2015 in Journal of Heat Transfer
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A general formulation of the spherical harmonics (PN) methods was developed recently to expand the method to high orders of PN. The set of N(N + 1)/2 three-dimensional second-order elliptic PDEs formulation and their Marshak boundary conditions for arbitrary geometries are implemented in the openfoam finite volume based cfd software. The results are verified for four cases, including a 1D slab, a 2D square enclosure, a 3D cylindrical enclosure, and an axisymmetric flame. All cases have strongly varying radiative properties, and the results are compared with exact solutions and solutions from the photon Monte Carlo method (PMC).

ACS Style

Wenjun Ge; Ricardo Marquez; Michael F. Modest; Somesh P. Roy. Implementation of High-Order Spherical Harmonics Methods for Radiative Heat Transfer on openfoam. Journal of Heat Transfer 2015, 137, 052701 .

AMA Style

Wenjun Ge, Ricardo Marquez, Michael F. Modest, Somesh P. Roy. Implementation of High-Order Spherical Harmonics Methods for Radiative Heat Transfer on openfoam. Journal of Heat Transfer. 2015; 137 (5):052701.

Chicago/Turabian Style

Wenjun Ge; Ricardo Marquez; Michael F. Modest; Somesh P. Roy. 2015. "Implementation of High-Order Spherical Harmonics Methods for Radiative Heat Transfer on openfoam." Journal of Heat Transfer 137, no. 5: 052701.

Journal article
Published: 01 November 2014 in Combustion and Flame
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Direct Numerical Simulations (DNS) of ethylene/air diffusion flame extinctions in decaying two-dimensional turbulence were performed. A Damköhler-number-based flame extinction criterion as provided by classical large activation energy asymptotic (AEA) theory is assessed for its validity in predicting flame extinction and compared to one based on Chemical Explosive Mode Analysis (CEMA) of the detailed chemistry. The DNS code solves compressible flow conservation equations using high order finite difference and explicit time integration schemes. The ethylene/air chemistry is simulated with a reduced mechanism that is generated based on the directed relation graph (DRG) based methods along with stiffness removal. The numerical configuration is an ethylene fuel strip embedded in ambient air and exposed to a prescribed decaying turbulent flow field. The emphasis of this study is on the several flame extinction events observed in contrived parametric simulations. A modified viscosity and changing pressure (MVCP) scheme was adopted in order to artificially manipulate the probability of flame extinction. Using MVCP, pressure was changed from the baseline case of 1 atm to 0.1 and 10 atm. In the high pressure MVCP case, the simulated flame is extinction-free, whereas in the low pressure MVCP case, the simulated flame features frequent extinction events and is close to global extinction. Results show that, despite its relative simplicity and provided that the global flame activation temperature is correctly calibrated, the AEA-based flame extinction criterion can accurately predict the simulated flame extinction events. It is also found that the AEA-based criterion provides predictions of flame extinction that are consistent with those provided by a CEMA-based criterion. This study supports the validity of a simple Damköhler-number-based criterion to predict flame extinction in engineering-level CFD models. © 2014 The Combustion Institute

ACS Style

Vivien R. Lecoustre; Paul G. Arias; Somesh P. Roy; Zhaoyu Luo; Dan C. Haworth; Hong G. Im; Tianfeng F. Lu; Arnaud Trouvé. Direct numerical simulations of non-premixed ethylene–air flames: Local flame extinction criterion. Combustion and Flame 2014, 161, 2933 -2950.

AMA Style

Vivien R. Lecoustre, Paul G. Arias, Somesh P. Roy, Zhaoyu Luo, Dan C. Haworth, Hong G. Im, Tianfeng F. Lu, Arnaud Trouvé. Direct numerical simulations of non-premixed ethylene–air flames: Local flame extinction criterion. Combustion and Flame. 2014; 161 (11):2933-2950.

Chicago/Turabian Style

Vivien R. Lecoustre; Paul G. Arias; Somesh P. Roy; Zhaoyu Luo; Dan C. Haworth; Hong G. Im; Tianfeng F. Lu; Arnaud Trouvé. 2014. "Direct numerical simulations of non-premixed ethylene–air flames: Local flame extinction criterion." Combustion and Flame 161, no. 11: 2933-2950.