Planar Detonation Wave Initiation in Large-Aspect-Ratio Channels

Jackson, Steve; Austin, Joanna; Shepherd, Joseph E.

doi:10.2514/1.21581

Cited by 11 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ramsay (1985) evaluated T c of PBX 9502 under both confined and unconfined conditions using a 'prism test', involving a wedge-shaped cuboid of PBX 9502 initiated with a line wave generator (Jackson, Austin & Shepherd 2006;Morris, Jackson & Hill 2009) at one trapezoidal face. A witness plate on the opposing face was dented if detonation successfully transited the wedge.…”

Section: Prior Scaling Measurementsmentioning

confidence: 99%

Scaling of detonation velocity in cylinder and slab geometries for ideal, insensitive and non-ideal explosives

Jackson

Short

2015

J. Fluid Mech.

View full text Add to dashboard Cite

Experiments were conducted to characterize the detonation phase-velocity dependence on charge thickness for two-dimensional detonation in condensed-phase explosive slabs of PBX 9501, PBX 9502 and ANFO. In combination with previous diametereffect measurements from a cylindrical rate-stick geometry, these data permit examination of the relative scaling of detonation phase velocity between axisymmetric and two-dimensional detonation. We find that the ratio of cylinder radius (R) to slab thickness (T) at each detonation phase velocity (D 0 ) is such that R(D 0 )/T(D 0 ) < 1. The variation in the R(D 0 )/T(D 0 ) scaling is investigated with two detonation shock dynamics (DSD) models: a lower-order model relates the normal detonation velocity to local shock curvature, while a higher-order model includes the effect of front acceleration and transverse flow. The experimentally observed R(D 0 )/T(D 0 ) (<1) scaling behaviour for PBX 9501 and PBX 9502 is captured by the lower-order DSD theory, revealing that the variation in the scale factor is due to a difference in the slab and axisymmetric components of the curvature along the shock in the cylindrical geometry. The higher-order DSD theory is required to capture the observed R(D 0 )/T(D 0 ) (<1) scaling behaviour for ANFO. An asymptotic analysis of the lower-order DSD formulation describes the geometric scaling of the detonation phase velocity between the cylinder and slab geometries as the detonation phase velocity approaches the Chapman-Jouguet value.

show abstract

Section: Prior Scaling Measurementsmentioning

confidence: 99%

Scaling of detonation velocity in cylinder and slab geometries for ideal, insensitive and non-ideal explosives

Jackson

Short

2015

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…An identical system was used by Austin et al [28,29] with a 4.2 m long rectangular narrow channel with a height of 152 mm and a width of 18 mm. The detonation is initiated by a planar wave generated by a C 2 H 2 -O 2 detonation created by a unique multi-channel initiator [58].…”

Section: Laser Induced Fluorescence Modelmentioning

confidence: 99%

Application of a laser induced fluorescence model to the numerical simulation of detonation waves in hydrogen–oxygen–diluent mixtures

Mével

Davidenko

Austin

et al. 2014

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

show abstract

“…2) were constructed that were identical in all aspects except for their channel geometries. A static initiator was designed and constructed as a prototype and a dynamic initiator was constructed for PDE applications, which require sensitive driver gas injection into the small channels [27]. All results presented were obtained with the dynamic initiator, which shaped the implosion from six series of square channels located on the inner cylinder.…”

Section: Initiator Designmentioning

confidence: 99%

“…The toroidal initiator was created by mapping the geometry of a planar wave initiator [27] to the surface of an aluminum cylinder such that the exit of each channel lies on a circle with the channels exhausting inward. (A planar wave initiator is used to create a planar detonation front from a single ignition point and an array of channels.)…”

Section: Initiator Designmentioning

confidence: 99%

Toroidal Imploding Detonation Wave Initiator for Pulse Detonation Engines

Jackson

Shepherd

2007

AIAA Journal

Self Cite

View full text Add to dashboard Cite

Imploding toroidal detonation waves were used to initiate detonations in propane-air and ethylene-air mixtures inside of a tube. The imploding wave was generated by an initiator consisting of an array of channels filled with acetylene-oxygen gas and ignited with a single spark. The initiator was designed as a low-drag initiator tube for use with pulse detonation engines. To detonate hydrocarbon-air mixtures, the initiator was overfilled so that some acetylene oxygen spilled into the tube. The overfill amount required to detonate propane air was less than 2% of the volume of the 1-m-long, 76-mm-diam tube. The energy necessary to create an implosion strong enough to detonate propane-air mixtures was estimated to be 13% more than that used by a typical initiator tube, although the initiator was also estimated to use less oxygen. Images and pressure traces show a regular, repeatable imploding wave that generates focal pressures in excess of 6 times the Chapman-Jouguet pressure. A theoretical analysis of the imploding toroidal wave performed using Whitham's method was found to agree well with experimental data and showed that, unlike imploding cylindrical and spherical geometries, imploding toroids initially experience a period of diffraction before wave focusing occurs. A nonreacting numerical simulation was used to assist in the interpretation of the experimental data.

show abstract

Planar Detonation Wave Initiation in Large-Aspect-Ratio Channels

Cited by 11 publications

References 7 publications

Scaling of detonation velocity in cylinder and slab geometries for ideal, insensitive and non-ideal explosives

Scaling of detonation velocity in cylinder and slab geometries for ideal, insensitive and non-ideal explosives

Application of a laser induced fluorescence model to the numerical simulation of detonation waves in hydrogen–oxygen–diluent mixtures

Toroidal Imploding Detonation Wave Initiator for Pulse Detonation Engines

Contact Info

Product

Resources

About