The diffraction of a planar detonation wave at an abrupt area change

摘要: Previous experimental work on the diffraction of a detonation wave at large and abrupt area change in tube, has shown that every system is characterized by critical tube diameter which quenching occurs. Zeldovich, Kogarko & Simonov (1956) established diameter, for oxy-acetylene with varying dilution nitrogen, lies between 500 700 times one-dimensional induction zone length. Later, Mitrovanov Soloukhin (1964) discovered that, same system, 10 or 13 transverse spacing flat channel cylindrical respectively. The two results are to be equivalent confirmed further experiments 75 × 6 mm flow two-dimensional.Smoked foil schlieren records show supercritical waves, re-ignition occurs sites along wedge formed head expansion from diffracting aperture criticality attained when site located apex wedge. A universal feature re-initiation, also observed liquid solid explosives, sudden appearance sweeps through compressed, but unreacted, gas dissociated shock-reaction regime; this signalled fine triple-point writing smoked-foil records.A criterion re-initiation formulated equating velocity gradient characterizes decay wavefront cell, obtaining diffracted shock front fan; an expression latter derived Whitham's (1957) theory non-reactive shocks. prediction good agreement observation.