噴流撞擊圓盤產生之液頁流場實驗研究

Abstract

本研究主要為檢視水鐘液頁流場的理論在微小尺寸下之適用性，理論部分採用Clanet【3】之先前研究結果。本文研究方法結合實驗與理論，探討在室溫室壓下，微小純水液柱碰撞固體平面後所形成的水鐘液頁流場成型特性及其邊緣霧化情形，並且試著從其所顯示的各式物理現象，推測出可能的物理原則，此外也改變流體性質與純水做為區別並探討流體性質所造成水鐘液頁成型之影響。探討主題主要可分成三個部分：(1)微型尺寸與典式理論之比較；(2)改變流體性質後對流場之影響；(3)改變噴嘴及碰撞平面直徑比之影響。本文結果顯示：(1)本文使用之微型尺寸與理論對照相符合；(2)改變流體性質後，水鐘輪廓及霧化情形有顯著的改變；(3)噴嘴與碰撞平面直徑比會影響液頁成形時具有的能量。

This investigation discusses whether the classical theory of water bell formation can be used to describe micrometer scale water jets based on the study of Clanet【3】on liquid sheets generated by jet impact. By combined experimental and theoretical inves-tigations of liquid sheets generated by water jet impact on solid discs and we study the atomization condition of liquid sheets in an atmospheric environment. The main work is divided into three parts: (1) The feasibility of classical theory applied to micrometer scale water jets；(2) The effect of surface tension；(3) The effect of jet-disc diameter ratio. The results reveal that: the classical theory of water bell formation can be applied at the micrometer scale, the effect of surface tension is an important characteristic in determining the shapes of water bell shape, and the jet-disc diameter ratio affects the energy of formation of liquid sheets.