Radiative Heat Transfer in Turbulent Combustion Systems PDF Download

Author: Michael F. Modest
Publisher: Springer
ISBN: 3319272918
Category : Science
Languages : en
Pages : 167

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Book Description
This introduction reviews why combustion and radiation are important, as well as the technical challenges posed by radiation. Emphasis is on interactions among turbulence, chemistry and radiation (turbulence-chemistry-radiation interactions – TCRI) in Reynolds-averaged and large-eddy simulations. Subsequent chapters cover: chemically reacting turbulent flows; radiation properties, Reynolds transport equation (RTE) solution methods, and TCRI; radiation effects in laminar flames; TCRI in turbulent flames; and high-pressure combustion systems. This Brief presents integrated approach that includes radiation at the outset, rather than as an afterthought. It stands as the most recent developments in physical modeling, numerical algorithms, and applications collected in one monograph.

Author: Rogério Goncalves Dos santos
Publisher:
ISBN:
Category :
Languages : en
Pages : 125

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Book Description
The combustion is one of the principal ways to produced energy used nowadays, it is also a complex phenomenon, where the turbulent flow, chemical reactions, different phases and different heat transfer phenomena can interact. Better understanding of these interactions is essential to improve the actual combustion system and to developed the new ones. The goal of this thesis is to study the interaction of the turbulent combustion with the thermal radiation by the use of three-dimensional numerical simulation. For that, using a computational tool named CORBA, a code for the combustion Large Eddy Simulation (LES) was coupled with a radiative heat transfer code. This technique allows the exchange of information between the two codes without big changes in their structure, then it is possible to take advantages of the different characteristic time from each phenomenon in a high performance parallel computational environment. In a first time, two-dimensional simulation of a turbulent propane/air premixed flame stabilized downstream a triangular flame holder has been realised. After the changing of the twodimensional radiation code for another three-dimensional one, the same configuration was simulated in 3D. A mesh with more than 4.7 millions cells for the combustion code (AVBP) and more than 3.3 millions cells for the radiation code (DOMASIUM) are used. Results show a changing in the temperature and species fields, as well as in the flame dynamics when the thermal radiation was taken into account, with a minor intensity in the three-dimensional simulations. This method, also, shows that it is possible to perform 3D complex simulations in a industrial acceptable time.

Author: Maria G. Carvalho
Publisher: Springer Science & Business Media
ISBN: 3642846378
Category : Science
Languages : en
Pages : 622

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Book Description
This volume contains the selected papers presented at the EUROTHERM SEMINAR No. 17 - Heat Transfer in Radiating and Combusting Systems held at Cascais from October 8th- 10th, 1990. The EUROTHERM COMMITTEE was created by representatives of the member countries of the European Communities for the organization and coordination of European Scientific events in the field of thermal sciences and their applications. The book is focused on the integration of the heat transfer and combustion. These two subjects have traditionally been considered separate disciplines. In reality, the two are closely interwoven. The central purpose of the book is to generate an effective cross fertilisation of the two at both the fundamental and applied levels. The book reports on: mathematical simulations of heat transfer in reacting systems, new measurements of and measurement techniques for the radiation properties of the intervening medium, and data and theoretical analyses which clarify the physical nature of the complex interactions between the radiation/convection heat transfer processes and the combustion and turbulence of real reacting flows.

Author: Raymond Viskanta
Publisher:
ISBN: 9781567003185
Category : Combustion engineering
Languages : en
Pages : 454

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Book Description
Destined to clarify the research, development, and design requirements in modern and computational terms needed for sustainable technological advances. Written for the combustion scientist/engineer to understand radiative effects on the pollution of the environment. Interrelates the process of thermodynamics, chemical kinetics, fluid mechanics, heat and mass transfer and turbulence. Includes computational design tools. Lays the foundation for modeling and prediction of chemically reacting combustion systems; collects data for operation of combustion devices. Analyzes the construction, use, and numerical results of combustion systems simulation.

Author: Michael F. Modest
Publisher: McGraw-Hill Science, Engineering & Mathematics
ISBN: 9780070426757
Category : Chaleur - Rayonnement et absorption
Languages : en
Pages : 0

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Book Description
Offers a comprehensive treatment of heat transfer. In addition to the standard topics usually covered, it also includes a number of modern state-of-the-art topics including: radiative properties of particles, generation of P-N approximation and collimated irradiation.

Author: Chandan Paul
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Detailed radiation modelling in advanced high-efficiency piston engines is recently getting attention due to their higher operating pressures and higher levels of exhaust gas recirculation (EGR), which make molecular gas radiation more prominent (absorption coefficient proportional to participating species concentration). Advanced high-efficiency engines also are expected to function closer to the limits of stable operation, where even small perturbations to the energy balance can have a large influence on system behavior. Here several different spectral radiation property models (including line-by-line LBL) and radiative transfer equation (RTE) solvers (including photon Monte Carlo PMC) have been implemented in an OpenFOAM-based engine CFD code. The influence of turbulence-radiation interactions (TRI) is determined by comparing results obtained using local mean values of composition and temperature to compute radiative emission and absorption with those obtained using a particle-based transported probability density function (tPDF) method. Simulations have been performed for full-load (peak pressure ~200 bar) and part-load (peak pressure ~85 bar) operation of a heavy-duty diesel engine with different levels of EGR. Differences in computed temperature fields, NO and soot levels, and wall heat transfer rates are shown for cases with and without TRI. Computed radiative emission and reabsorption with TRI are higher compared to those obtained without TRI for the same operating condition. However, with TRI, the increase in radiative reabsorption is greater than the increase in radiative emission. Hence, with consideration of TRI, the net radiative heat loss is lower than for the no-TRI case for the same operating condition. Finally, guided by results from PMC/LBL (PMC RTE solver with LBL spectral model) radiation model on Volvo 13-liter heavy-duty diesel engine, a simplified stepwise-gray spectral model in combination with P1 RTE solver is proposed. Using this proposed model, radiative emission, reabsorption and radiation reaching the walls are computed at part-load and full-load operating conditions with different levels of EGR and soot. The results are compared with those of PMC/LBL, P1/FSK and P1/Gray radiation models to assess the proposed models accuracy and computational cost. The results show that the proposed P1/StepwiseGray model can calculate reabsorption locally and globally with less than 10% error (with respect to PMC/LBL) at a small fraction of the computational cost of PMC/LBL (a factor of 30) and P1/FSK (a factor of 15). In contrast, error in computed reabsorption by the P1/Gray model is as high as 60%. It is expected that the simplified model should be broadly applicable to high-pressure hydrocarbon-air combustion systems, with or without soot.

Author: American Society of Mechanical Engineers. Winter Annual Meeting
Publisher: American Society of Civil Engineers
ISBN:
Category : Science
Languages : en
Pages : 100

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Book Description

Author: Sebastian Ferreyro Fernandez
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The design strategies for the next generation of low-emission combustion systems are highly focused on reducing pollutant emissions, and designers need to perform numerical simulations that incorporate detailed soot and radiative heat transfer models. In addition, most combustion devices operate under turbulent flow regimes; therefore the effects of turbulent fluctuation on soot and radiative heat transfer models need to be accounted for. 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. 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.

Author: Jr., Charles E. Baukal
Publisher: CRC Press
ISBN: 142003975X
Category : Science
Languages : en
Pages : 568

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Book Description
Industry relies heavily on the combustion process. The already high demand for energy, primarily from combustion, is expected to continue to rapidly increase. Yet, the information is scattered and incomplete, with very little attention paid to the overall combustion system. Designed for practicing engineers, Heat Transfer in Industrial Combustion e

Author: Kshitij V. Deshmukh
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Turbulent combustion is encountered in many industrial applications such as combustors, nozzles, turbines, engines and furnaces. The increasing concern for pollutant emissions to the environment has led to a wide interest in studying the process in detail using numerical simulation with an aim to develop predictive models that would minimize expensive experiments. Three main approaches in this direction are direct numerical simulation (DNS), large eddy simulation (LES) and Reynolds average simulation (RAS). Moreover, the presence of high temperatures in turbulent combustion results in substantial heat transfer by radiation. Most work until today has either simplified or neglected radiation. This leads to neglect of turbulence?radiation interactions (TRI). In this work, DNS is coupled with a photon Monte Carlo method to solve the radiative transfer equation (RTE) to isolate and quantify TRI. A canonical statistically one-dimensional turbulent premixed combustion system is studied. The inflow boundary condition is improved to introduce turbulence and to help simulate a quasi-stationary flow. Both emission TRI and absorption TRI were found to be significant. A statistical analysis showed that using a moving average over time of the radiative source term reduces statistical noise and saves valuable computational resources without affecting the overall solution. For the first time, a third-order spherical harmonics method, P3 approximation is coupled with DNS to replace the photon Monte Carlo method. A canonical turbulent premixed combustion system is simulated and TRI are studied at large-to-small optical thicknesses. Emission TRI was found to be significant at all optical thickness, while absorption TRI was important at large and intermediate optical thickness and negligible at the optically thin limit. The implementation of the P3 approximation is seen as a viable alternative to the costly photon Monte Carlo method. Elliptic equations are typically solved in RAS-based and LES-based modeling and the P3 approximation consists of six elliptical partial differential equations (PDEs). It is hoped that the demonstration of use of the P3 approximation will generate interest for it to be included in future LES and RAS approaches and developments. A low-order model for LES using a?-PDF approach is also developed for a canonical statistically one-dimensional turbulent nonpremixed system. The mixture fraction and its variance are inputs to the model to obtain a PDF of mixture fraction. With the knowledge of the PDF of mixture fraction, the quantities that are functions of mixture fraction are convoluted with the mixture fraction PDF to obtain the chemical source term and the radiative emission terms. The mean profiles are predicted correctly but the nonlinear terms of radiative emission are not captured accurately, as the?-PDF cannot provide information for the higher-order terms. Still, as a one-equation model to be used as a first pass for LES simulation, this model has its advantages in that it is easy to implement and uses negligible additional computational resources over what is required for LES without any models.