Spray Detonation Initiation by Controlled Triggering of Electric Dischargers

2005 ◽  
Vol 21 (1) ◽  
pp. 54-64 ◽  
Author(s):  
S. M. Frolov ◽  
V. Ya. Basevich ◽  
V. S. Aksenov ◽  
Polikhov S. A.
Keyword(s):  
Detonation Initiation ◽  
Spray Detonation

Optimization study of spray detonation initiation by electric discharges

Shock Waves ◽  
2005 ◽  
Vol 14 (3) ◽  
pp. 175-186 ◽  
Author(s):  
S. M. Frolov ◽  
V. Ya. Basevich ◽  
V. S. Aksenov ◽  
S. A. Polikhov
Keyword(s):  
Detonation Initiation ◽  
Electric Discharges ◽  
Optimization Study ◽  
Spray Detonation

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

Shock Waves ◽  
2021 ◽  
Author(s):  
S. Bengoechea ◽  
J. Reiss ◽  
M. Lemke ◽  
J. Sesterhenn
Keyword(s):  
Shock Wave ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Detonation Initiation ◽  
Axisymmetric Nozzle ◽  
Exponential Factor ◽  
Pulsed Detonation Engine ◽  
Pulsed Detonation ◽  
Detonation Engine ◽  
Adjoint Approach

AbstractAn 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.

scholarly journals Detonation initiation by shock focusing at elevated pressure conditions in a pulse detonation combustor

2020 ◽  
Vol 12 ◽  
pp. 175682772092171
Author(s):  
Fabian E Habicht ◽  
Fatma C Yücel ◽  
Joshua AT Gray ◽  
Christian O Paschereit
Keyword(s):  
Success Rate ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Initial Pressure ◽  
Detonation Initiation ◽  
Major Influence ◽  
Mean Flow ◽  
Shock Focusing ◽  
Pulse Detonation

This work contains experimental investigations on the correlation of the detonation initiation process via a shock-focusing device with various initial pressures and mass flow rates. A pulse detonation combustor is operated with stoichiometric hydrogen--air--oxygen mixtures in single cycle operation. A rotationally symmetric shock-focusing geometry evokes the onset of a detonation by the focusing of the reflected leading shock wave, while a blockage plate at the rear end of the test rig is applied to induce an elevated initial pressure. The results show that the reactivity has a major influence on the success rate of detonation initiation. However, measurements with different blockage plates suggest that the mass flow rate has to be considered as well when predicting the success rate. Three main statements can be drawn from the results. (1) An increase in the mean flow velocity induces higher velocity fluctuations which result in a stronger leading shock ahead of the accelerating deflagration front. (2) An increase in the initial static pressure reduces the critical shock strength that must be exceeded to ensure successful detonation initiation by shock focusing. (3) Since the initial pressure is directly linked to the mass flow rate, these contrary trends can cancel each other out, which could be observed for 40% vol. of oxygen in the oxidizer. High-speed images were taken, which confirm that the detonation is initiated in the center of the converging--diverging nozzle due to focusing of the leading shock.

Investigation of Flow Field Properties on Detonation Initiation

2006 ◽  
Author(s):  
Patrick Hutchenson ◽  
Chris Brophy ◽  
Jose Sinibaldi ◽  
Charles Cathey ◽  
Martin Gunderson
Keyword(s):  
Flow Field ◽  
Detonation Initiation

Shock Reflection Detonation Initiation Studies for Pulse Detonation Engines

2005 ◽  
Vol 21 (6) ◽  
pp. 1117-1125 ◽  
Author(s):  
B. de Wit ◽  
G. Ciccarelli ◽  
F. Zhang ◽  
S. Murray
Keyword(s):  
Detonation Initiation ◽  
Shock Reflection ◽  
Pulse Detonation Engines ◽  
Pulse Detonation
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