利用LIF感溫技術量測渦環在逆溫層之速度及溫度場

Abstract

本實驗利用會隨溫度造成亮度上變化的螢光染料(Rhodamine B、Rhodamine 110)，在不影響原流場結構的前提之下，利用雷射螢光測溫法(Laser Induced Fluorescence)和質點顯像測速儀(Particle Image Velocimetry)觀測渦環進入溫層後從主動混合到被動混合的變化與影響。 本文內容詳細介紹此技術之原理、實驗設備架設、校準及實驗方法建立，並將此技術應用於溫層中渦環的流場量測。在此分別就保持一固定動量之渦環在均勻環境與逆溫層環境中，分析其溫度、速度與渦度等物理量之分佈與變化情形，並驗證此量測技術之實用性，最後再使用數值分析軟體Comsol Multiphysics探討驗證此渦環流場的物理現象。

This experiment utilizes the fluorescent dyes (Rhodamine B、Rhodamine 110) that shine with their intensity proportional to its temperature. Combining the use of laser-induced fluorescence (LIF) and particle image velocimetry (PIV), we are able to measure the fluid flow without disturbing the flow. On the dissertation, we use the technique to measure the transient phenomena of a vortex ring moving in a thermally inversion ambient. The principle of the LIF technology, experimental set-up, and calibration are detailed. We measured vortex rings with a fixed momentum in both thermally homogeneous and thermally inverse ambients for comparison. Use this technology in combining with PIV for the present topic of interest is proven feasible, in additional, Numerical analysis using commercial software Comsol Multiphysics is also performed.