Streamwise Interaction of a Stream of Drops

Abstract

In this study the interaction of a stream of water drops aligned in a vertical direction was examined experimentally using a free-falling drop apparatus which provided different gaseous flows namely no flow (quiescent air vg = 0 m/s) convective air flow (vg = 0 3 m/s and 0 5 m/s) and hot flow (vg = 2 5 m/s) The initial drop diameter (di) was kept at 900 μm In addition there were three different numbers of drops to consider in the study two drops three drops and a drop stream and three initial dimensionless drop spacings Si ? 2 5 5 and 10 were selected in the experiment In the second part two different initial drop diameters were considered 900 μm and 1100 μm The results showed that the merged collision of drops is controlled by the wake effect which depends on the initial drop spacing (Si) Reynolds number (Re) initial drop diameter (di) and number of drops The initial drop spacing has a dominant influence in comparison with the others In the downward moving process of drops with given values of Si and di the initial merged collision of the first two drops was observed after which they merged into a large drop; thereafter this large drop was caught by the rear drop to achieve the second merged collision The first merged collision occurred either along the same axis or in an off-center situation but the second merged collision occurred only in the off-center situation The results showed that the merged collision position shifted to the downstream region with increases in vg Si di or the number of drops under fixed di and vg

Date of Award	2016 Jul 12
Original language	English
Supervisor	Ta-Hui Lin (Supervisor)