Transient Convection Driven Flow Field and Temperature Distribution during Photo-Deposition of Pdamna Films from Solution

在溶液中進行光沉積聚聯乙炔晶膜成長過程中流場及溫度分佈所驅動的瞬態對流

洪儒珍(R. J. Huang) ； 龍瀛天(Y. T. Long)

《中國航空太空學會學刊》 27卷4期 (1995/12) Pp. 267-288

https://doi.org/10.6124/TAASRC.199512_27(4).01

摘要

本文採用一組數學表達式模擬研究了幾種不同方向的重力加速條件下，伴隨著用紫外光輻照的聚聯乙炔晶膜成長而產生的傳熱過程。通過數值計算獲得了在紫外光輻照過程中流動及溫度分佈隨時間的發展過程。計算表明，在通常的重力加速度環境下，受到紫外光輻照的晶膜的成長過程是在非常複雜的迴流條件下進行的。顯然在地面環境下，如此復雜的流場是無法獲得各向均勻的晶膜。換言之，爲了成長出各向均句，顆拉精細的晶膜，必須在微重力環境中用紫外光對材料隨行蝠照。流體力學模擬作爲一種工具，可以用來爲最佳實驗方案的擬定提出有益建議，以達到處理最佳非線性光學材料之目標。

關鍵字

自然對流換熱 ； 微重力 ； 晶體成長 ； 有機非線性光學材料

並列摘要

A set of mathematical formulation is adopted to study a growth of thin films by exposure to ultraviolet (UV) light driven heat transfer process under various directions of gravitational acceleration. A series of time animation of the initiation and development of flow and temperature profiles during the course of (UV) light exposure has been obtained through the numerical computation. Computations show that the material processing by UV light exposure has been accomplished by the heat transfer process through a fairly complicated flow pattern of recirculation under normal gravitational acceleration. It is obvious that there is no way to produce a homogeneous thin crystalline films with fine grains under such a complicated flow. Pattern of recirculation with a non-uniform temperature distribution on the ground. Also, there is no growth of good quality thin film in a stably stratified medium without convection: Growth of thin films under horizontal direction gravitational acceleration introduce a flow zone perpendicular to the gravitational acceleration which is favorable to produce a homogenous thin crystalline films. However, horizontal direction gravitational acceleration also induce an unfavorable flow field in parallel to the direction of gravitational acceleration which is responsible to initiate a complicated flow pattern of recirculation. In other words, it is necessary to carry out material processing by UV light exposure in a microgravity environment for the sake to grow a homogenous crystalline films with fine grains. Fluid mechanics simulation can be used as a tool to suggest most optimistic way of experiment with best setup to achieve the goal of processing best nonlinear optical materials.

並列關鍵字

solid rockets ； combustion instability ； flow turning