Numerical investigation of detonation initiation by a focusing shock wave

Bengoechea, Sergio; Reiß, Julius; Lemke, Mathias; Sesterhenn, Jörn

doi:10.1007/s00193-020-00962-z

Cited by 4 publications

(1 citation statement)

References 27 publications

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“…Habicht et al 10 experimentally investigated the detonation initiation by shock focusing at elevated pressure conditions in a pulse detonation combustor and found that an increase in the initial static pressure reduced the critical shock strength which was exceeded to ensure successful detonation initiation by shock focusing. Bengoechea et al 11 represented a numerical study of detonation initiation by means of a focusing shock wave using a one-step chemical model with variable parameters optimized by the adjoint approach in terms of the induction time. The results gave a comprehensive description of the shock-induced detonation initiation.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on detonation initiation process in the chamber with characteristic structures of the dual-mode scramjet combustor

Wei

Wang

Qin

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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In order to improve the performance of traditional ramjet, a ramjet based on pulse detonation (PD-Ramjet) instead of isobaric combustion was proposed. Several special-shaped detonation chambers which retained the characteristic structures of the dual-mode scramjet combustor were designed. Characteristic structures included the expansion channel and the cavity. The filling process and detonation initiation process of the stoichiometric hydrogen/air mixture under the incoming flow condition of the sub-combustion mode were studied in the detonation chambers with characteristic structures by two-dimensional numerical simulation method, and the influences of the characteristic structures on the filling process and detonation initiation process were analyzed. The simulation and analysis results indicated that the hydrogen concentration at both sides of the chamber near the outlet was low due to the structure of the expansion channel, and the pressure and velocity of the detonation wave decreased gradually after the expansion channel. The cavity had a significant influence on the filling process, which resulted in the uneven hydrogen concentration downstream the cavity, especially near the outlet of the chamber. The intensity of the detonation wave attenuated to a certain extent by reason of the cavity, where the peak pressure first decayed due to the sudden expansion of the flow path and then rose owing to the reflection at the cavity aft wall.

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Section: Introductionmentioning

confidence: 99%

Numerical study on detonation initiation process in the chamber with characteristic structures of the dual-mode scramjet combustor

Wei

Wang

Qin

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Adjoint-based optimisation of detonation initiation by a focusing shock wave

et al. 2021

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An optimisation study of a shock-wave-focusing geometry is presented in this work. The configuration serves as a reliable and deterministic detonation initiator in a pulsed detonation engine. The combustion chamber consists of a circular pipe with one convergent–divergent axisymmetric nozzle, acting as a focusing device for an incoming shock wave. Geometrical changes are proposed to reduce the minimum shock wave strength necessary for a successful detonation initiation. For that purpose, the adjoint approach is applied. The sensitivity of the initiation to flow variations delivered by this method is used to reshape the obstacle’s form. The thermodynamics is described by a higher-order temperature-dependent polynomial, avoiding the large errors of the constant adiabatic exponent assumption. The chemical reaction of stoichiometric premixed hydrogen-air is modelled by means of a one-step kinetics with a variable pre-exponential factor. This factor is adapted to reproduce the induction time of a complex kinetics model. The optimisation results in a 5% decrease of the incident shock wave threshold for the successful detonation initiation.

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