Ezddin Hutli

Frequency in Shedding/Discharging Cavitation Clouds Determined by Visualization of a Submerged Cavitating Jet

Visualization of a highly submerged cavitating water jet was done by high-speed camera photography in order to study and understand the jet structure and the behavior of cloud cavitation within time and space. The influencing parameters, such as injection pressure, nozzle diameter and geometry, and nozzle direction (convergent and divergent), were experimentally proven to be very significant. Periodical shedding and discharging of cavitation clouds have been also analyzed and the corresponding frequency was determined by cloud shape analysis. Additionally, the dependence of this frequency on injection pressure and nozzle geometry has been analyzed and a simple formula of correspondence has been proposed. The formula has been tested on self-measured and literature data. The recordings of sonoluminescence phenomenon proved the bubble collapse everywhere along the jet.

An Experimental Investigation of Cavitating Jet Dynamic Power and Cavitation Intensity

The principal focus of this investigation were the effect of hydrodynamic and geometrical parameters on cavitating jet dynamic power and cavitation intensity under different flow conditions. Jet performance indicators were taken to be the erosion rate of the target surface and the size of the erosion area.. In addition, flow visualization was used as an additional tool to demonstrate the effect of dynamic power on the cavitating jet characteristics. The results show that the erosion rate can be used an indicator of the strength of the impinging jet to establish a correlation between the jet power and the pertinent experimental parameters. In addition, the importance of non-dimensional standoff distance was investigated and an analytical relationship established between it and the jet intensity. These expressions are proposed for calculating the efficiency of cavitating jets.Copyright

APPEARANCE OF HIGH SUBMERGED CAVITATING JET: THE CAVITATION PHENOMENON AND SONO-LUMINESCENCE

In order to study jet structure and behaviour of cloud cavitation within time and space, visualization of highly submerged cavitating water jet has been done using Stanford Optics 4 Quick 05 equipment, through endoscopes and other lenses with Drello3244 and Strobex Flash Chadwick as flashlight stroboscope. This included obligatory synchronization with several types of techniques and lenses. Images of the flow regime have been taken, allowing calculation of the non-dimensional cavitation cloud length under working conditions. Consequently a certain correlation has been proposed. The influencing parameters, such as; injection pressure, downstream pressure and cavitation number were experimentally proved to be very significant. The recordings of sono-luminescence phenomenon proved the collapsing of bubbles everywhere along the jet trajectory. In addition, the effect of temperature on sono-luminescence recordings was also a point of investigation. [Projekat Ministarstva nauke Republike Srbije, br. TR35046]