Streamwise Interaction of Three Drops

• Main Authors: Li-TeHuang, 黃礪德
• Other Authors: Ta-Hui Lin
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/02410737230159553352

碩士 === 國立成功大學 === 機械工程學系 === 103 === The interaction of three drops in the direction of the stream is studied experimentally using a free-falling drop apparatus which provides different gaseous flows, cold flow (vg = 0 - 0.5 m/s) and a hot flow (vg = 2.5 m/s). Both water and dodecane were used in the experiments, and thus there are two main parts to discuss. In the downward movement of three aligned drops with given values of di and Si, the first two drops first merge into a large drop, which then merges with the remaining drop. It was found that the position of the merging drop collisions which resulted in merged shifted downstream with larger initial drop diameter, larger initial drop spacing, and higher initial gas velocity due to the weakened wake effect. The initial drop spacing (Si) was more dominated to interaction of three drops. The leading merged collision included along the same axis condition and under the off-center condition, but the final merged collision occurred only under the off-center condition. The oscillation period of the leading merged increased with increasing initial drop diameter, but the final merged did not exhibit a oscillate cycle. Three aligned dodecane drops moved downward only in hot flow. The three dodecane drops were affected by the interactions among the thermal expansion, convective effect caused by the different flame structures in the combustion chamber, and exhibited three main merged modes. The different flame structure would affect the vaporization rate (k) of all drops.