An experimental study into the mechanisms of hydro- and sonoluminescence and initiation of microexplosive fuel atomization

Abstract

We have experimentally studied hydro- and sonoluminescence phenomena during the flow of hydraulic oil in a narrow channel, with an original experimental setup used. The study substantiates the assumptions that liquids, being condensed media, can exhibit mechanisms of quasi-plastic momentum transfer at strain rates of έ > 105 s-1. One of the manifestations of localized shear in liquids upon reaching shear rates of έ > 105 s-1 in the near-wall region is hydroluminescence. It has been experimentally established that there is a threshold value of the strain rate έ ~ 105 s-1 (Re ~ 1350, ∇P ~ 1.2 GPa/m) at which a sharp increase in the intensity of hydro- and sonoluminescence signals is observed. The proposed designs of measuring cells made it possible to separate signals characteristic of hydro- and sonoluminescence manifestations. Statistical processing of signals obtained from a photomultiplier allowed us to establish differences in the laws of distribution of hydro- and sonoluminescence pulses, which confirms the qualitative differences in the phenomena under study. Hydroluminescence is caused by the implementation of a pseudoplastic momentum transfer mechanism in liquids, while sonoluminescence is associated with cavitation mechanisms. In conclusion, recommendations are proposed concerning the manufacture of fuel injector channels for initiating microexplosive fuel atomization by activating ‘hot spots’ associated with localized shifts in liquids.