Figure 9
Estimation of diameter of a population of 30 H2 bubbles around the cathodic tool at a common time-frame of 71.67 ms for (a) tool-based ECM process at 20 V (b) tool-based hybrid laser-ECM process at parameter set 20 V/30 µJ (c) and at parameter set 20 V/60 µJ. In the bubble plot shown above, the centre of the spheres (bubbles) represent the estimated diameter and the diameter of spheres is proportional to the actual diameter of the bubble. The purpose of spherical representation is to enable a qualitative interpretation of bubble size. The diameters represented above are estimated in PFV ver. 3691 by pixel to distance calibration of image. Only the bubbles around the tool were measured and the smaller bubbles in the bulk flow were not included as they are already being flushed out. Bubbles smaller than 25 µm were difficult to estimate and hence were not included in the measurements.
