Influence of density, viscosity and interfacial tension on liquid droplet dynamics from an open-ended vertical capillary pipe. An experimental investigation

The principal objective of the present work is to measure the surface tension of liquids by using a drop weight method by adding new techniques to measure exact drop size and shape, which is linked to the fall velocity and the air drag forces. This thesis is purely experimental. The measurement of the surface tension by Drop weight Method can be implemented with essential laboratory equipment on its most straightforward configuration, but if a detailed analysis is desired can also be implemented with more advanced equipment to see what is involved inside the experiment, this also implies a higher level of complexity on data processing and understanding of the results. In order to test the method, it was decided to use fluids that can be easily found in the laboratory and within the most extensive possible range. The principle of this method is to use burette radius for the droplet size as a reference and use drop weight as the most direct measure. While droplet can have different size, shape and air resistance, drop mass is constant. In addition to that, not only the surface tension was measured, but also the Python OpenCV library was used to analyze the shape of the matrix, how droplets are formed on the tip of the burette and the diameter of each droplet via slow-motion video frames. Once the data acquired, the surface tension was attempted to be calculated by exact droplet sizes. The associated error to the calculations is no larger than 1.92 %. Finally, the possible reasons for these errors are briefly discussed