孔口幾何與流體性質對毛細噴流碎裂長度之效應

The Effects of Nozzle Geometry and Fluid Property on the Breakup Length of Capillary Jet

張枝成(Jy-Cheng Chang) ； 沈孟燊(Meng-Shen Shen) ； 盧久章(Jiu-Zhang Lu)

《中國航空太空學會學刊》 32卷4期 (2000/12) Pp. 315-321

https://doi.org/10.6124/TAASRC.200012_32(4).06

摘要

本研究以三種不同性質的流體通過厚度分別爲0.03mm與0.06mm之孔口板，且孔口板之幾何形狀分別爲圓形、方形與三角形，並以單一粒徑液滴產生器產生毛細噴流，分別調整流量爲6.5、7.2、8.4、9.7及11.1 ml/min等，以觀察噴流液柱在最佳震盪及不震盪的情形下液柱的神裂長度變化。本實驗研究參數主要爲Re數、We數及孔口幾何形狀，而有關於毛細噴流碎裂的特性，主要是觀察各參數對碎裂長度的影響並將實驗數據迴歸成經驗式；對於在最佳震盪情形下，其經驗式爲：BLn/T=8.254×We^0.561〔Re^0.008×(T/D)^0.987〕；對於在無人爲外加震盪情形下，其經驗式爲BLv/T=13.494×We^0.593/〔Re^0.157×(T/D)^0.567〕；而對於有無外加震盪之通式則爲：BL/T=16.878×We^0.560/〔Re^0.092×(T/D)^0.859×(I+V(下標 opt)/V)1.721〕

關鍵字

毛細噴流 ； 孔口幾何 ； 碎裂長度

並列摘要

The objective of the present work is to study the effects of the nozzle geometry on the breakup length of the capillary jet, where the working fluid was subjected to either artificial optimum vibration or without vibration, by employing the experimental measurements and microphotography techniques. The experimental work is unique in that the nozzle geometry is rated in different length/diameter ratio and shape, and well characterized, which is almost absent in the previous work. For reasons of completeness, the viscosity and surface tension are considered by using three different fluids. The parameter study includes the effects of the length/diameter ratio, the orifice geometry, Weber number and Reynolds number. Survey the breakup length of liquid jet under optimal and natural vibration, an empirical formula about the breakup length for the working fluid subjected to natural vibration was obtained: BLn/T=8.254×We^561/〔Re^0.008×(T/D)^0.987〕; for the working fluid subjected to artificial optimum vibration: BLv/T=13.494×We^0.593/〔Re^0.157×(T/D)^0.567)〕; and finally for the general case: BL/T=16.878×We^0.560/〔Re^0.092×(T/D)^0.859×(I+V(subscript opt)/V)^1.721〕.

並列關鍵字

Capillary Jet ； Orifice Geometry ； Breakup Length