Large-eddy simulation (LES) of turbulent combustion is a relatively new research field. Much research has been carried out over the past years, but to realize the full predictive potential of combustion LES, many fundamental questions still have to be addressed, and common practices of LES of nonreacting flows revisited. The focus of the present review is to highlight the fundamental differences between Reynolds-averaged Navier-Stokes (RANS) and LES combustion models for nonpremixed and premixed turbulent combustion, to identify some of the open questions and modeling issues for LES, and to provide future perspectives.

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Large-eddy simulation of turbulent combustion

Toward accommodating realistic fuel chemistry in large-scale computations

Biomass gasification has yet to consolidate its position compared to other techniques for exploiting biomass energy. Neither the research conducted nor the plants built in recent decades, nor even government support for this technology, have provided a sufficient boost to increase the level of implementation of gasification despite its advantages in aspects such as greater efficiency and the reduction in CO2 emissions, as there are numerous other methods of biomass energy conversion that provide stiff competition. In this paper, gasification techniques have been reviewed in depth and the main factors to be considered in the design of a gasification plant have been outlined. It is observed that there are a great number of factors involved in design and operation of a gasification plant, and many of them are critical. Moreover, having designed a plant according to certain specifications, there is a high probability that these initial conditions can vary, causing a malfunction of the plant.

Biomass gasification for electricity generation: Review of current technology barriers

Computational fluid dynamic (CFD) simulations that include realistic combustion/emissions chemistry hold the promise of significantly shortening the development time for advanced high-efficiency, low-emission engines. However, significant challenges must be overcome to realize this potential. This paper discusses these challenges in the context of diesel combustion and outlines a technical program based on the use of surrogate fuels that sufficiently emulate the chemical complexity inherent in conventional diesel fuel. The essential components of such a program are discussed and include: (a) surrogate component selection; (b) the acquisition or estimation of requisite elementary chemical kinetic, thermochemical, and physical property data; (c) the development of accurate predictive chemical kinetic models, together with the measurement of the necessary fundamental laboratory data to validate these mechanisms; and (d) mechanism reduction tools to render the coupled chemistry/flow calculations feasible. In parallel to these efforts, the need exists to develop similarly robust models for fuel injection and spray processes involving multicomponent mixtures of wide distillation character, as well as methodologies to include all of these high fidelity submodels in computationally efficient CFD tools. Near- and longerterm research plans are proposed based on an application target of premixed diesel combustion. In the near term, the recommended surrogate components include n-decane, iso-octane, methylcyclohexane, and toluene. For the longer term, n-hexadecane, heptamethylnonane, n-decylbenzene, and 1-methylnaphthalene are proposed.

/pdf/development-of-an-experimental-database-and-kinetic-models-4jhnabq7ub.pdf

Development of an Experimental Database and Kinetic Models for Surrogate Diesel Fuels

First Year – Fall ......................... .............................................................................................. Credits MAT 210 ..................................... Calculus I ............................................................................. 4.0 ENG 110...................................... Expository Writing ............................................................. 3.0 CHE 210 ...................................... Chemistry I .......................................................................... 4.0 HUM 100 OR SOC 101 OR PSY 101 ........................................................................................ 6.0 Subtotal ...................................... .............................................................................................. 17

Chemical Engineering Scienceについて

http://pepiot.mae.cornell.edu/pdf/Narayanaswamy_CF_2014.pdf

A chemical mechanism for low to high temperature oxidation of n-dodecane as a component of transportation fuel surrogates

A component library framework for deriving kinetic mechanisms for multi-component fuel surrogates: Application for jet fuel surrogates

A new 4 in. (102 mm) diameter fluidized-bed reactor has been built and used to study the effect of biomass particle size on the yield of light gas and tar compounds during gasification. Batch experiments were conducted with white oak milled into four sphere sizes with diameters of 6, 13, 18, and 25 mm, at reactor bed temperatures of 500, 600, 700, 800, and 900 °C. As expected, the yields of light gas increase with temperature but then reach a plateau above 800 °C. As the particle size increases, a decrease in the formation of light gases, accompanied by an increase in the formation of char, is observed. For larger particle sizes, the commonly used power law dependence of particle devolatilization time with sphere diameter holds true and the transition from heat- and mass-transport control to kinetic control as particle diameter decreases is illustrated. Measurements of the organic compounds present in the syngas are performed using a molecular beam mass spectrometer (MBMS). These measurements indicate tha...

/pdf/biomass-pyrolysis-and-gasification-of-varying-particle-sizes-16f4b4o4vg.pdf

Biomass Pyrolysis and Gasification of Varying Particle Sizes in a Fluidized-Bed Reactor

http://ctflab.mae.cornell.edu/papers/Pepiot,%20Desjardins.%202012.%20Numerical%20analysis%20of%20the%20dynamics%20of%20two-%20and%20three-dimensional%20fluidized%20bed%20reactors%20using%20an%20Euler-Lagrange%20approach.pdf

Perrine Pepiot

Papers

A chemical mechanism for low to high temperature oxidation of n-dodecane as a component of transportation fuel surrogates

A component library framework for deriving kinetic mechanisms for multi-component fuel surrogates: Application for jet fuel surrogates

Biomass Pyrolysis and Gasification of Varying Particle Sizes in a Fluidized-Bed Reactor

Numerical Analysis of the Dynamics of Two- and Three-Dimensional Fluidized Bed Reactors using an Euler-Lagrange Approach

Numerical characterization and modeling of particle clustering in wall-bounded vertical risers