臺灣大學: 機械工程學研究所王興華蔡宣志Tsai, Hsuan-ChihHsuan-ChihTsai2013-04-012018-06-282013-04-012018-06-282011http://ntur.lib.ntu.edu.tw//handle/246246/256006本文主要是研究液滴於另一液相，五種不同管徑下的阻力變化及運動現象探討。而實驗系統系於液滴在靜止流體的狀態，溫度控制在25至28℃間、常壓(1atm)條件下進行實驗，為了避免質傳現象的發生，採用水當作液滴，正庚烷、正十二烷及正十六烷做為實驗中系統的連續流體，所得到的雷諾數範圍在0.34至350間，而液滴與管徑之比值在0.02至0.74間。 實驗結果顯示，液滴在管徑17.3及10 mm的條件下，受到的阻力現象與剛球的趨勢相同，亦即在λ為0.08至0.14的範圍下，其邊界效應還不明顯，但隨著λ越大，液滴的阻力就會跳脫了剛球趨勢線，且在低雷諾數的範圍內，此現象會更加地明顯；另一方面，液滴的運動軌跡與雷諾數、流體性質λ息息相關，例如在λ<0.6時，若要跟管壁碰撞，其首要條件就是雷諾數要大於200左右，而此時的升力為一吸引力，但在λ>0.7時，液滴在雷諾數約為50左右就能碰觸到管壁，進而使液滴的速度因碰撞的關係而下降。The experiment discusses the drag and the motion of liquid droplets through anaqueous phase contained in five vertical cylinders of various diameters. The temperature is controlled between 25-28℃, and the pressure is 1 atm. To avoid the mass transition, we use water to be the droplet, and use heptane dodecane and hexadecane to be the continued fluid. The range of Reynolds numbers are between 0.34 to 350, and the rang of droplet-to-tube diameters ratio are between 0.02 to 0.74. The present data show that the droplet drag coefficients are similar to the rigid sphere in 17.3 and 10 mm diameters, which means that the wall effect is not obvious in the range of λ from 0.08 to 0.14, but the drag line will be escape from rigid sphere line when λ is getting bigger, and it becomes more obvious in low Reynolds number range; furthermore, the droplet motion is associated with Reynolds number, the physical properties of fluids, and λ, such as when λ is smaller than 0.6, the condition for droplet could approach to the wall that its Reynolds number must come up to 200, and the lift is a attractive force at same time, but when λ is bigger than 0.7, it can be hit the walls as Reynolds number is 50, and the drop velocity become slower because of repeatedly collide with the wall.2500594 bytesapplication/pdfen-US阻力；雷諾數；震盪；邊界因子drag force；Reynolds number；oscillations；wall factorthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/256006/1/ntu-100-R98522320-1.pdf