Dynamics and stability of lean-premixed swirl-stabilized combustion

Advances in scientific computing have made modelling and simulation an important part of the decision-making process in engineering, science, and public policy. This book provides a comprehensive and systematic development of the basic concepts, principles, and procedures for verification and validation of models and simulations. The emphasis is placed on models that are described by partial differential and integral equations and the simulations that result from their numerical solution. The methods described can be applied to a wide range of technical fields, from the physical sciences, engineering and technology and industry, through to environmental regulations and safety, product and plant safety, financial investing, and governmental regulations. This book will be genuinely welcomed by researchers, practitioners, and decision makers in a broad range of fields, who seek to improve the credibility and reliability of simulation results. It will also be appropriate either for university courses or for independent study.

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Verification and Validation in Scientific Computing

Combustion dynamics constitutes one of the most challenging areas in combustion research. Many facets of this subject have been investigated over the past few decades for their fundamental and practical implications. Substantial progress has been accomplished in understanding analysis, modeling, and simulation. Detailed laboratory experiments and numerical computations have provided a wealth of information on elementary dynamical processes such as the response of flames to variable strain, vortex rollup, coupling between flames and acoustic modulations, and perturbed flame collisions with boundaries. Much recent work has concerned the mechanisms driving instabilities in premixed combustion and the coupling between pressure waves and combustion with application to the problem of instability in modern low NO x heavyduty gas turbine combustors. Progress in numerical modeling has allowed simulations of dynamical flames interacting with pressure waves. On this basis, it has been possible to devise predictive methods for instabilities. Important efforts have also been directed at the development of the related subject of combustion control. Research has focused on methods, sensors, actuators, control algorithms, and systems integration. In recent years, scaling from laboratory experiments to practical devices has been achieved with some successebut limitations have also been revealed. Active control of combustion has also evolved in various directions. A number of experiments on laboratory-scale combustors have shown that the amplitude of combustion instabilities could be reduced by applying control principles. Full-scale terrestrial application to gas turbine systems have allowed an increase of the stability margin of these machines. Feedback principles are also being explored to control the point of operation of combustors and engines. Operating point control has special importance in the gas turbine field since it can be used to avoid operation in unstable regions near the lean blowoff limits. More generally, closed loop feedback concepts are useful if one wishes to improve the combustion process as demonstrated by applications to automotive engines. Many future developments of combustion will use such concepts for tuning, optimization, and emissions reduction. This article proposes a broad survey of these fast-moving areas of research.

Combustion dynamics and control: Progress and challenges

An Introduction to Magnetohydrodynamics

Review of code and solution verification procedures for computational simulation

The method of manufactured solutions is used to verify the order of accuracy of two finite-volume Euler and Navier–Stokes codes. The Premo code employs a node-centred approach using unstructured meshes, while the Wind code employs a similar scheme on structured meshes. Both codes use Roe's upwind method with MUSCL extrapolation for the convective terms and central differences for the diffusion terms, thus yielding a numerical scheme that is formally second-order accurate. The method of manufactured solutions is employed to generate exact solutions to the governing Euler and Navier–Stokes equations in two dimensions along with additional source terms. These exact solutions are then used to accurately evaluate the discretization error in the numerical solutions. Through global discretization error analyses, the spatial order of accuracy is observed to be second order for both codes, thus giving a high degree of confidence that the two codes are free from coding mistakes in the options exercised. Examples of coding mistakes discovered using the method are also given. Copyright © 2004 John Wiley & Sons, Ltd.

Verification of Euler/Navier–Stokes codes using the method of manufactured solutions

Modeling of turbulent premixed flames in the flamelet regime

This paper reports on the progress of a new compressible flow simulation code being developed at Sandia National Laboratories. The code called Premo is a CFD module that is part of a much larger multimechanics code framework called SIERRA. The goal of the Premo project is to deliver a general purpose CFD capability for designers and analysts of aerodynamics of flight vehicles. SIERRA provides unstructured mesh data services common to many computational mechanics codes. Utilizing the framework allows for rapid development of physics modules. In addition, the SIERRA framework provides an interface that will make it possible to conduct multiphysics simulations between physics modules to solve such problems as aero-thermal vehicle heating and aero elasticity in the future. Current code capabilities are demonstrated by solving one-, two- and threedimensional flow problems.

https://cfwebprod.sandia.gov/cfdocs/CompResearch/docs/02-2160C.pdf

Thomas M. Smith

Papers

Verification of Euler/Navier–Stokes codes using the method of manufactured solutions

Modeling of turbulent premixed flames in the flamelet regime

SIERRA/Premo-A New General Purpose Compressible Flow Simulation Code

Comparison of Reconstruction Techniques for Unstructured Mesh Vertex Centered Finite Volume Schemes

A new class of finite element variational multiscale turbulence models for incompressible magnetohydrodynamics