This paper presents visualization and image processing of spray structure affected by cavitation bubbles and cavitating flow patterns. Experiments were conducted for a better understanding of cavitation and resulting flow regimes. Cavitation is generated with sudden pressure drop across a 4.5 mm long short micro-channel with an inner diameter of 152 μm connected to the setup using proper fittings. Generated cavitation bubbles and fluid flow patterns were observed by using a high speed camera. The spray structure was observed in four different segments and mainly the droplet evaluation in the lower segments for low upstream pressures was analyzed using several image processing techniques including contrast adjustments and morphological operators. Moreover, fluid flow regimes for different upstream pressures were investigated, and the flow patterns were analyzed in the separated regions of the spray.
@inproceedings{ghorbani2015visualization, title={Visualization and image processing of spray structure under the effect of cavitation phenomenon}, author={Ghorbani, Morteza and Alcan, Gokhan and Yilmaz, D and Unel, M and Kosar, A}, booktitle={Journal of Physics: Conference Series}, volume={656}, number={1}, pages={012115}, year={2015}, organization={IOP Publishing} }
Hydrodynamic cavitation is an effective and alternative treatment method in various biomedical applications such as kidney stone erosion, ablation of benign prostatic hyperplasia tissues and annihilation of detrimental cells. In order to effectively position the orifice of bubbly cavitating flow generator towards the target and control the destructive cavitation effect, cone angle of multi-phase bubbly flow and distributions of scattered bubble swarms around main flow must be determined. This paper presents two vision based solutions to determine these quantities. 3D Gaussian modeling of multi-phase flow and edge slopes of cross-section are used to estimate the cone angle in a Kalman filter framework. Scattered bubble swarm distributions around main flow were assumed as a normal distribution and analyzed with the help of covariance matrix of the bubble position data. Hydrodynamical cavitating bubbles were generated from 0.45 cm long micro probe with 152μm inner diameter under 10 to 120 bars pressures and monitored via Particle Shadow Sizing technique. Proposed methods enabled to quantize the increasing inlet pressure effect on bubbly cavitating multi-phase flow.
@inproceedings{alcan2015vision, title={Vision based cone angle estimation of bubbly cavitating flow and analysis of scattered bubbles using micro imaging techniques}, author={Alcan, Gokhan and Ghorbani, Morteza and Kosar, Ali and Unel, Mustafa}, booktitle={IECON 2015-41st Annual Conference of the IEEE Industrial Electronics Society}, pages={003473--003474}, year={2015}, organization={IEEE} }