常壓非熱電漿滅菌裝置之模擬研究II(2/3年)計畫

Abstract

非熱電漿技術在生醫領域上之應用乃近年來之熱門研究課題，目前之趨勢已由早期之低壓電漿應用，逐漸轉向常壓大氣電漿技術之開發。但相關之大氣電漿滅菌機制、反應器設計(間接或直接電漿)及最佳操作條件等均尚處於研究階段中，多以實驗探討之，耗時及成本亦高。一般來說，電漿模擬相當耗時。另鑑於近年來高速電腦之急遽增加與普及，平行處理計算的普及，可能在常壓電漿模擬技術上引致重大之進展。唯平行計性應用於非熱電漿的模擬，仍屬少見，甚為可惜。因此，在此針對此常壓非熱電漿滅菌裝置進行模擬，以求達到最佳化設計，提供實驗設計參考，以利核能研究所在非熱電漿技術研發及在生醫領域上之應用與推廣。 在過去一年，本計畫現階段達成的目標如下: 第一年完成工作已包括：1) 收集非熱電漿滅菌文獻及建立資料庫，探討在非熱電漿中的電磁場、紫外線、氧化基及加熱等反應速率常數。2) 建立有限差分方法(FDM)之常壓非熱電漿場1D平行化模擬並驗證其正確性。3) 模擬氦氣(Helium gas)，氮氣(Nitrogen gas)等氣體，在不同時間尺度下(10kHz ~ 13.56MHz)反應性物種之時間變化。

在未來兩年，本計畫預定達成目標如下: 第二年預定工作將包括： 1. 建立有限差分方法(FDM)之二維及二維軸對稱模擬平行計算模組，計算電漿粒子能量分布。2. 加入二維及二維軸對稱 Navior-Stoke equation 模組計算中性氣體及自由基的流場分布. 3. 探討不同電漿氣體流速、電源功率與電極電壓等參數間與自由基產生量、種類、及時空分布情形之相互關聯性。4. 提供電漿滅菌反應器一最佳化參數，供實驗設計參考。

第三年預定工作將包括：1. 建立有限差分方法(FDM)之2D~3D模擬平行計算模組。2.探討電漿滅菌裝置之內部空間分布、內部流場如電磁場(含紫外線)、速度場、壓力場、溫度場等數值模擬計算，對電漿密度與自由基之影響研究，並提出最佳設計及條件。3. 探討待處理滅菌物件之幾何尺寸，擺設位置對電漿滅菌裝置之滅菌效能、影響評估與最適化研究。 在本申請書中, 僅就第二年預定工作進行描述。

In recent years, non-thermal atmospheric-pressure plasma has attracted tremendous attention in bio-medical applications. Technical development and interest in sterilization of bacterial cells has evolved from low-pressure plasma into atmospheric-pressure plasma. However, most of the studies in this direction are in their infant stage, which the mechanism of sterilization, design of plasma reactor and operating conditions heavily rely on trial-and-error method that is costly and time-consuming. It is also known that plasma simulation is in general very time-consuming. This can be greatly improved by the recent advancement of parallel computing. Thus, in this proposal we aim to study the plasma sterilization through simulations, which can possibly help the design of the plasma reactor. This will in turn boost the research capability of INER in the field of bio-medicine by using non-thermal atmospheric-pressure plasmas. In the last year, the major tasks in this 3-year project achieved are summarized as follows: In the 1st year, we have completed the following tasks: 1) Literature survey in the field of non-thermal atmospheric-pressure plasma sterilization and related mechanisms, which possibly include the rate constants due to EM field, ultra-violet, or oxygen radical has been completed. 2) A parallelized 1D non-thermal atmospheric-pressure plasma simulation code using finite difference method, in which fluid modeling has been developed and verified. 3) The developed code to simulate discharges by different gases (Helium gas and Nitrogen gas) concerning the distribution of free radicals driven by various frequencies of the power supply in the range of 10kHz~13.56MHz has been completed. In the future, the major tasks will be expected to achieve are summarized as follows: In the 2nd year the tasks include: 1) To extend the parallelized 1D code into parallelized 2D and 2D axisymmetric non-thermal atmospheric-pressure plasma simulation code using FDM; 2) To add 2D and 2D axis symmetry Navior-Stock simulation code into plasma module to compute the distributions of neutral and radial; 3) To conduct plasma simulations to obtain the temporal and spatial distributions of radicals and charged particles by varying the flow speeds, gap distance, thickness of dielectrics and external power. 4) To provide the design parameters for the plasma reactor for sterilization. In the 3rd year the tasks include: 1) To extend and validate previous parallelized 2D code into parallelized 3D non-thermal atmospheric-pressure plasma simulation code using FDM 2) To conduct plasma simulations to obtain the temporal and spatial distributions of radicals and charged particles by varying the flow speeds, gap distance, thickness of dielectrics, external power and other possible geometric factors. 3) To provide the design parameters for the plasma reactor for sterilization. In this proposal, only the tasks in the second year are described in detail.