3rd SPANISH HPC COMBUSTION WORKSHOP

RED ESPAÑOLA DE SUPERCOMPUTACIÓN

July 2nd, 2021
Barcelona Supercomputing Center (BSC)
Department of Computer Applications in Science and Engineering

About The Event

The HPCCOMB2021 combustion workshop is dedicated to getting together combustion researchers across Spain, and share experiences and issues related to the modelling of combustion systems. In particular, the workshop has the following objectives:

• To disseminate information about the use of supercomputing facilities for combustion
applications at the national level,

• To encourage the use of computing resources from the RES in the community,

• To share successful / unsuccessful experiences on combustion modeling,

• To enable national collaborations for national and EU projects,

• To disseminate high-level research to invited industries.

This community has large legacy, is very active on research and has a strong link with the industry and energy sectors, but still, it is not a large consumer of HPC resources at the national level.

Many researchers access to computing power via local clusters, international collaborations, PRACE or are simply not aware of the RES. We would like to take the opportunity to present the capabilities of Marenostrum 4 and the available information about Marenostrum 5, show the new updates of the RES (larger number of resources at disposal for researchers compared to two years ago), the storage application and all the services available from the RES that can be used by
the combustion community.

The opening this year will be given by Professor César Dopazo, Founding Member of the Spanish Royal Academy of Engineering and Emeritus Professor at the Universidad de Zaragoza and we have confirmed as plenary speakers Professor Antonio L. Sánchez, Full Professor at University of California San Diego (UCSD) and Dr. Bénédicte Cuenot, leader of the Combustion Research Group at CERFACS. Contributions to the workshop are invited in all areas of numerical combustion. Contributed presentations (15 minutes talk followed by 5 minutes discussion) should be submitted as abstracts (max 500 words). From the full list of abstracts, about 9 contributions will be selected for oral presentation, while the rest will be allocated as 3-5 minute “flash talks”.

Please send your abstracts to daniel.mira@bsc.es or carmen.jimenez@ciemat.es before the 16th June 2021.

Please note that registration is also necessary. The link to register is given here: https://us02web.zoom.us/meeting/register/tZYqce2upjMjHtKBe2cvN54HBEL2P3BZUTtD.

Keynotes Speakers

Short Bio

Agenda

Abstracts

César Dopazo

University of Zaragoza (Spain)

Benedicte Cuenot

CERFACS (France)

Antonio Sánchez

University of California San Diego(USA)

Short Bio

César Dopazo

University of Zaragoza, Spain

Aero Engineer, Madrid Polytechnic University (1969)

PhD, Mechanical Engineering, State University of New York, Stony Brook (1973)

Post-Doctoral Research Associate, Johns Hopkins University, Baltimore (1974-75)

Associate Scientist, Brookhaven National Laboratory, Long Island, New York (1975-1978)

Engineer, Technical Department, UNESA (Electric Utilities), Madrid (1978-1980)

Professor of Fluid Mechanics, School of Engineering and Architecture, University of Zaragoza (1980-present)

Visiting Scientist: Brookhaven National Laboratory, UC Davis, USC, Ecole Centrale de Lyon, UC Berkeley (1979-2002)

Founder and Director of the Combustion Research Laboratory (LITEC), Zaragoza (1991-2001)

Founding Academician, Royal Academy of Engineering (RAI), Spain (1994-present)

General Director, CIEMAT, Spanish National Center for Energy and Environmental Research (2002-2004)

Member, Advisory Group on Energy and Climate Change, President of the European Commission, J.M. Durao Barroso (2008-2012)

Publications on turbulent reacting flows, turbulence, two-phase flows, cavitation, energy planning,…

Research projects and industrial contracts on: i) Lean-Premixed-Prevaporized Aero-Engine Technology (Coordinator, Consortium of European Gas Turbine Manufacturers and Universities, led by Rolls Royce, 1992-1998); ii) Combustion of solid, liquid and gaseous fuels (Spanish Electric Utilities and Energy companies, 1987-2002); iii) Heavy oil upgrading by ultrasonic cavitation (Oil Company, 2007-2010); iv) Technical and economic potential of
Renewable Energy Sources in Spain (Electric Utilities, 2006-2008); v) Energy Road Maps 2010-2040 for Central Asia (Coordinator, Asian Development Bank, 2011-2014)

Currently: Honorary Professor (University of Zaragoza, 2019-present); Research interests on turbulent premixed flames and hydrodynamic cavitation.

Dr-HdR B. Cuenot obtained her engineering and master degree from Ecole Centrale de Paris in 1990. After one year as research engineer in the University of Boulder (CO, USA), she came back to France where she defended her PhD in 1995 and HdR in 2000, both in the field of numerical combustion.

She is now the leader of the combustion research group at CERFACS, developing advanced and massively parallel softwares for the numerical simulation (DNS and LES) of turbulent reacting flows, plasma flows and heat transfer (including thermal radiation) in industrial systems. With these tools she addresses various topics such as pollutant emissions, ignition and extinction, combustion efficiency or thermal fatigue of combustion chambers in the fields of propulsion and energy production.

Dr. Cuenot teaches combustion and fluid mechanics in various universities and has authored more than 100 peer-reviewed journal papers. She has participated to many collaborative projects at the national and international level, and is much experienced in coordinating european projects, mostly financed by the European Commission where she also acts as an expert evaluator.

She has been distinguished as a Fellow of the Combustion Institute in 2018 and is a member of the Editorial Board of Combustion and Flame since 2018. She is co-Chair of the 39th International Symposium in Combustion, to be held in Vancouver in july 2022.

Benedicte Cuenot

CERFACS (France)

Antonio Sánchez

University of California San Diego(USA)

Antonio Sánchez is a professor in the Department of Mechanical and Aerospace Engineering at UC San Diego. Before joining UCSD in 2014, he served as professor for 20 years at the Universidad Carlos III in Madrid, Spain.

He is interested in fundamental problems that involve the interplay of fluid mechanics, transport processes, and chemical reactions. Current research topics include fire whirls, flame dynamics in liquid-propellant rocket engines, and flow and transport in the central nervous system.

His research approach takes advantage of the disparity of the length and time scales encountered in these complex problems to simplify the solutions, often by application of asymptotic methods that help to identify simpler sub-problems and serve to extract the fundamental underlying physics

Agenda

Abstracts

Physics/DNS-based examination of some issues on turbulent reacting flows

Authors: César Dopazo

Institution: University of Zaragoza

Abstract: Some issues on turbulent reacting flows of constant and variable density fluids are revisited using a combination of physical ideas and available DNS datasets. Some of the following topics are examined:

– Deformation of non-material elements defined by iso-scalar surfaces. SDF.

Classical concepts on strain and rotation of material elements, extended to non-material lines, surfaces and volumes embedded in reactive fronts, allows simple physical interpretation of thermochemical strain rates normal and tangential to iso-scalar surfaces. Differences for constant and variable density fluid flows are apparent from the analysis of various DNS databases. A simple interpretation of the surface density function (SDF) is presented.

– Scalar-fluctuations and their dissipation rates. Quasi-stationary PDFs.

Scalar-fluctuations and their gradients are narrowly linked, although determined by different ranges of length and time scales. The relevant time scales, which control the evolution of the scalar variance and the scalar-fluctuation dissipation rate are examined. The interaction of small-scale flow structures and chemical reactions seems to naturally emerge in the transport equation for the scalar-fluctuation dissipation rate. The existence of quasi-stationary inert scalar PDFs is scrutinized, via DNS.

– Local quenching of reacting fronts. Existence of singular points.

The time evolution of scalar-gradients, which quantifies the local mass and heat transfer rates, is solely determined by the flow and thermochemical normal strain rates. The latter should be a relevant variable to establish criteria of local quenching of reaction fronts. Some DNS preliminary results are presented. The existence of singular points is also investigated.

– Burning rates.

The parametric dependence on Reynolds and Karlovitz numbers of burning rates in turbulent reactive systems is an issue of high practical interest. A theoretical analysis is presented, in which relevant parameters emerge.

– Scalar fluctuation spectra. Combustion generated enstrophy.

Information on relevant length scales in combustion systems is provided either by spatial scalar auto-correlation functions or by scalar spectra. An analysis “à la Corrsin” for simple statistically homogeneous turbulent flow of a constant density fluid with a scalar undergoing a linear chemical reaction is presented to illustrate the main problems. Recent results for variable density reactive flows are discussed. The issue of combustion generated turbulence is presented through the analysis of enstrophy budgets. Some DNS results are presented and discussed.

A list of topics deserving further detailed consideration by experts on numerical simulation of turbulent combustion is outlined

Modelling and simulation of soot formation and evolution in turbulent flames

Authors: B. Cuenot, L. Gallen & E. Riber

Institution: CERFACS

Abstract: Soot emission is a major concern for thermal engines, furnaces and all combustion-based processes. Soot particles being dangerous for human health when they are in too high concentration, their emission level is subjected to more and more constraining regulations.

To fulfill these obligations, manufacturers are engaged in the development of low-soot burners, acting on the fuel formulation, the injection system and the operating conditions. The production and evolution of soot particles result however from a number of complex and interacting non-linear phenomena, which put in difficulty trial-and-error methods. High fidelity numerical simulation is then essential for the prediction of soot in real systems and the design of the next generation of low-soot burners.
CERFACS has recently developed a complete model for the soot formation, transport and oxidation in turbulent flames and complex geometries (Gallen, PhD 2020). The approach is based on a Lagrangian description of the soot particles, coupled to a semi-detailed chemical mechanism based on the Analytically Reduced Chemistry (ARC) concept. This approach allows to include soot precursors in the flame calculation which are known to be the key element of soot formation. Particular efforts have been put on the Lagrangian Soot (LST)
tracking algorithm to maintain high computing and parallel efficiency. With this approach, the description of the particle size distribution comes with almost no additional cost, and any particle property, such as morphology for example, can be easily included. In this lecture, the modelling approach followed to predict soot within the Large Eddy Simulation (LES) framework implemented in the in-house, massively parallel code AVBP (www.cerfacs.fr/avbp7x) will be described. Both physical phenomena and numerical aspects of the model will be detailed and illustrated in academic cases. The performance and accuracy of the approach will finally be assessed on practical configurations, also allowing to identify limitations and paths for improvement.

Swirling dynamics in liquid-pool fires

Authors: Antonio Sánchez

Institution: UCSD

Abstract: Fire whirls are vortical columns with a concentrated burning core. They are seen to occur often in large-scale fires, both in wildland and urban conflagrations, with disastrous consequences for people and surroundings. An extreme example of their destructive power is the fire whirl that followed the 1923 Tokyo earthquake, which incinerated 38,000 people in less than fifteen minutes. Pool fires, consisting of axisymmetric pools of burning liquid fuel have emerged as a widely used canonical

configuration from which to study the dynamics of large fires (and fire whirls), serving as a reference to validate numerical simulations and theory. There is interest in the quantification of the different liquid-pool-fire combustion regimes corresponding to different levels of ambient circulation, namely, axisymmetric puffing, fire whirls, dwarf fire whirls, and blue whirls, as well as characterization of a number of fluid-mechanical phenomena that control their transition, including global instabilities, vortex breakdown, and edge-flame detachment and lift-off. The present talk will summarize recent experimental findings concerning these different phenomena as well as accompanying theoretical and numerical descriptions. Specific attention will be given to the steady axisymmetric structure of the cold boundary-layer flow surrounding fire whirls, which is needed to write consistent boundary conditions accounting for the ambient swirl level. Numerical solutions will be presented for fire whirls over liquid-fuel pools, including results for large swirl, when the fire whirl is seen to transition to a new type of whirling flame, with a fundamentally different structure consisting of a light blue cone at the base, a bright ring, and a purple haze above. A close connection is established between the structure of these so-called “blue whirls” and the emergence of a vortex-breakdown bubble, the latter enabling flame stabilization and inducing a hysteretic behavior. Much more research is needed to obtain good quantitative knowledge of many of the intriguing phenomena that will be reviewed during this talk.

Location

Barcelona Supercomputing Center

Address: Calle Jordi Girona 31, 08034 Barcelona

Workshop room: Rectorado Building, Sala de Juntas, 1st floor