Hydrodynamic cavitation, nanobubble implosion, TeraHertz vibration, and correlated energy aspects

In the last two decades a large amount of evidence have been collected by the research group of Professor Carpinteri about compositional changes and neutron emissions in solid bodies subjected to fracture tests. The cause of the compositional variations of medium-weight elements in the analysed specimens and of the revealed anomalous neutron radiations, which clearly indicated the nuclear nature of the phenomenon, was detected in the effect of nanoscale perturbations and mechanical instabilities in the solid matter. The development or the coalescence of the nanoscale instability was found to produce TeraHertz pressure waves (defined as “phonons”), that expand throughout the specimen crystal lattice and that are believed to be able to establish resonance with the Debye frequencies of the medium-weight elements, producing consequent fission reactions usually called LENR. Departing from the field of fracture mechanics, the study of the effect of piezonuclear reactions led to the discovery of a wide field of possible practical applications, including the earthquake prediction, the structural damage monitoring and the study of the Earth’s crust, atmosphere and ocean compositional evolutions in time. As well as for nanoscale fractures in rocks and artificial specimens, the implosion of nanobubbles produced by the cavitation phenomenon in a water solution enriched by iron salts has been supposed to be the cause of the compositional changes and of the anomalous neutron emissions revealed simultaneously to the cavitation tests. The aim of the present thesis was to deepen the comprehension of the cavitation phenomenon as regards the effects on a water solution enriched by metal ions, focusing in particular on the study of the extra-heath generations and of the thermal energy emissions obtained from the promoted reactions. In order to obtain a reliable parameter to evaluate the thermal efficiency of the cavitation process, two different assessment methods for the Coefficient Of Performance in the steady-state condition were developed and applied, passing from a first extrapolation procedure to a final direct estimate. Although some differences between the results of the two methods were revealed, both of them allowed to quantify significant exceedances of the output thermal and mechanical energies with respect to the input electrical supply. As a consequence of that, the calorimetric monitoring of different geometries of nozzles led to the definition of some improvement factors to be considered for the possible future implementation of cavitation reactors for industrial applications, especially in terms of pump turning velocities, working pressures and internal geometries of the cavitators. In addition to the results of the calorimetric tests, a series of optic measurements of the dimensions of the bubbles produced by cavitation seemed to confirm the importance of nanoscale perturbations and TeraHertz-frequency phonons for the promotion of the LENR, encouraging to more deepened studies on the subject.