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Revisiting Deflagration-Detonation Transition in the context of carbon-free energy production – ReDDT

Revisiting Deflagration to Detonation Transition in the context of carbon-free energy production

This project presents a new and disruptive paradigm for solving the difficult problem of the dynamics of hydrogen detonations in a way convenient for the simulation of real flow configurations. The ultimate goal is to develop reliable models to be applied to the use, the storage and the transportation of carbon-free fuels, such as hydrogen

Revitalize the combination of the most advanced theoretical and analytical tools with modern numerical methods to tackle challenging physical aspects on detonations dynamics.

The objective of the present project is to set up theoretical models by asymptotic analyses, <br />representing accurately the dynamics of detonations in hydrogen-air mixtures. Physical phenomena pertaining to the inner structure of the waves will be included in the analysis, which is usually not the case. The mathematical formulation will be useful to guide in the physical analysis and shed more insight into the key parameters to better control carbon-free combustion systems and also improve safety regulation. Used to solve key problems in canonical configurations, the models will be validated by carefully controlled Direct Numerical Simulation (DNS) using the most advanced high-order algorithms. The challenging problems of Deflagration to Detonation Transition (DDT), Direct Initiation of Detonation (DID) and cellular fronts of strongly unstable Cellular Detonations (CD) will be addressed along these lines.

The ReDDT project is a joint effort bringing together two teams of researchers from the CORIA and IRPHE laboratories.
The CORIA lab has a strong and consolidated experience in the development of high-order numerical methods with applications to compressible, turbulent, high-speed, reactive flows.
The IRPHE lab represents an international reference in the establishment of novel theoretical analyses to tackle open questions in the field of reactive flows and detonations.
The two labs, which have already interacted in the past on theoretical and numerical studies of shock dynamics (three archival papers), shall develop breakthrough theoretical and numerical techniques to increase the understanding and the knowledge of the deflagration to detonation transition (DDT) and related phenomena. The major results will be in the form of best practice guidelines for the modeling of detonation in CFD (computational fluid dynamics), with direct implications within the context of industrial safety.

The dynamics of spherical gaseous detonations is controlled by small modifications of its inner structure which is thin compared to the radius. The direct initiation process is a typical example of such a sensitivity. For large activation energy, a critical radius is identified, illustrating a quasi-steady curvature-induced quenching of spherical detonations. Direct numerical simulations confirm such critical radius but also show that strong unsteadiness of the inner-detonation-structure is involved. The critical dynamics of the direct initiation of detonation is studied by asymptotic methods. In the limit of small heat release, it is show that the problem can be reduced to a single hyperbolic equation with curvature terms.
The above theoretical findings are confirmed by numerical simulations and improved insight is achieved for both stable and unstable detonations.
Similarly, the stability of one-dimensional gaseous detonations are revisited using both asymptotic analysis and high-order numerical simulations. The double limit of small heat release and a ratio of specific heats close to unity is considered, and attention is focused on weakly unstable detonations in the Chapman-Jouguet regime. It is shown that the time-dependent velocity of the lead shock can be obtained as the solution of a single hyperbolic equation for the flow. From this, the threshold activation energy for transition to instability and the oscillation frequency can be obtained. These theoretical findings have been validated against a set of direct numerical simulations of one-dimensional detonations in the same limit, performed using the high-order spectral difference scheme with minimal numerical dissipation. Values of detonation parameters at the instability threshold obtained from numerical simulations have been systematically compared against their theoretical counterparts, confirming the validity of the proposed asymptotic theory.

The results will pave the way for many practical applications, including generic criteria for the initiation of detonations and also the random apparition of super-knock in future engines powered by hydrogen combustion. The results obtained will present sufficiently fundamental and generic characters to be useful in the more general framework of safety issues, where detonations are at sake.

[1] H. Tofaili, G. Lodato, L. Vervisch and P. Clavin. One-dimensional dynamics of gaseous detonations revisited. Submitted to Combustion and Flame.
[2] P. Clavin, R. Hernandez-Sanchez, B. Denet, Asymptotic analysis of the critical dynamics of spherical gaseous detonations. Submitted to Journal of Fluid Mechanics.
[3] H. Tofaili, G. Lodato, L. Vervisch and P. Clavin. One-dimensional dynamics of gaseous detonations revisited. European Combustion Meeting 2021.
[4] H. Tofaili, G. Lodato, L. Vervisch and P. Clavin. Detonation stability: New paradigms for the control of rotating detonation engines. 5ème Colloque INCA, 7-8 Avril 2020, SAFRAN.

This project presents a new and disruptive paradigm for solving the difficult problem of the dynamics of hydrogen detonations in a way convenient for the simulation of real flow configurations.

The use, the storage and the transportation of carbon-free fuels, such as hydrogen, require the control of random and violent combustion phenomena, as the devastating detonation waves, which can occur suddenly in industrial plants.

Because performing multiple and detailed experiments under such extreme conditions is not an option, actual safety regulation, optimisation and design mostly rely on global correlations and numerical simulations. To be relevant, such simulations should accurately describe the strongly transient behaviours characterising the initiation and the propagation of these waves.

However, because of the wide range of scales involved, in both chemical kinetics and flow physics, actual computer capabilities do not allow for precisely capturing the unsteadiness of the inner structure of the wave together with the large scale flow motions. Since this inner structure actually controls the initiation and the dynamics of detonation waves at the largest flow scales, the prediction capabilities of the numerical simulations stayed so far very limited.

The objective of the present project is to set up theoretical models by asymptotic analyses, representing accurately the dynamics of detonations in hydrogen-air mixtures. The mathematical formulation will be useful to guide in the physical analysis and shed more insight into the key parameters to better control carbon-free combustion systems and also improve safety regulation.

Used to solve key problems in canonical configuration, the models will be validated by carefully controlled Direct Numerical Simulation (DNS) using the most advanced high-order algorithms. The challenging problems of Deflagration to Detonation Transition (DDT), Direct Initiation of Detonation (DID) and cellular fronts of strongly unstable Cellular Detonations (CD) will be addressed along these lines.

It is thus proposed to revitalize the combination of the most advanced theoretical and analytical tools with modern numerical methods to tackle these challenging issues. The team of this project will follow a strategy they proved recently successful for the multidimensional dynamics of shocks waves.

The results will pave the way for many practical applications, including generic criterion for the initiation of detonations and also the random apparition of \emph{super-knock} in future engines powered by hydrogen combustion. The results obtained will present a character sufficiently generic to be useful in the more general framework of safety issues, where detonations are at sake.

Project coordination

Guido Lodato (COMPLEXE DE RECHERCHE INTERPROFESSIONNEL EN AEROTHERMOCHIMIE)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

IRPHE Institut de recherche sur les phénomènes hors équilibre
CORIA COMPLEXE DE RECHERCHE INTERPROFESSIONNEL EN AEROTHERMOCHIMIE

Help of the ANR 291,600 euros
Beginning and duration of the scientific project: December 2018 - 42 Months

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