Nozzle Cavitation and Rock Erosion Experiments Reveal Insight into the Jet Drilling Process

Mixing Process in the Jet Flow of Lobed Nozzle

The vortical and turbulent structure changes in the near field (X/D<3.0) of the jet mixing flow caused by a lobed nozzle had been investigated experimentally in the present study. The techniques of planar Laser Induced Fluoresce (LIF) and Particle Image Velocimetry (PIV) were used to accomplish the flow visualization and velocity field measurements. The experimental results showed that, compare...

Effect of Injection Pressure and Size of Nozzle Throat of a Cavitating Jet on Cavitation Peening

Abstract Cavitation peening is a peening method using impacts at cavitation bubble collapses generated by a cavitating jet. In order to introduce compressive residual stress avoiding damage on the peened surface, residual stress of stainless steel was investigated at various cavitating conditions. It was revealed that the large cavitating jet at low injection pressure such as 30 MPa can introdu...

The Volume Factor in Cavitation Erosion

Use of jet cavitation, however, occurs through an exit nozzle whose diameter can be changed, thereby changing volume with changing velocity. The results of such a change is shown to tie cavitation damage more powerfully to volume flow than to velocity. A specific example is in cavitation erosion of a high strength igneous rock which remained virtually undamaged at 70 MPa driving pressure but wa...

Influence of nozzle geometry and injection conditions on the cavitation flow inside a diesel injector

Cavitation and turbulence in a diesel injector nozzle has a great effect on the development and primary breakup of spray. However, the mechanism of the cavitation flow inside the nozzle and its influence on spray characteristics have not been clearly known yet because of the internal nozzle flow complexities. In this paper, a comprehensive numerical simulation is carried out to study the intern...

Mitophagy: New Insight into the Cardiovascular Aging