- 學位論文
常壓氦氣及氦氣/氧氣電漿之模型研究
Modeling Study of Atmospheric He and He/O2 Glow Discharge
摘要
中文摘要 本研究以Bolsig軟體求解波滋曼方程式(Boltzmann equation)求得電漿中之電子特性值，並以其為基礎，分別建立He與He/O2常壓電漿之零維電漿模型與一維電漿模型，探討電漿特性隨功率、氧氣配比變化之趨勢，最後以生成速率分析(Rate of Production)尋求電漿之主要反應路徑。 在求解波滋曼方程式方面，發現在相同分配電場下，當氧氣配比提高後，電子能量會向低能量分佈，He電漿加入氧氣後則需要更多能量才能激發電漿。另外預測常壓He/O2電漿之電子溫度約在30000 ~35000。 在He與He/O2零維常壓電漿模型研究發現，He電漿主要物種為He*、He2*、He2+及電子，能量主要損耗於He之彈性碰撞，當加入微量氧氣後，激發態物種濃度下降，離子變為O2+為主，另外由於氧氣為陰電性氣體，因此O2-的出現使電子密度下降，能量主要損耗於O2之解離反應，電子溫度隨氧氣配比提升而先降後升。 在He與He/O2一維常壓電漿模型研究發現，於電場施加時，物種濃度之分佈大致皆與零維電漿模型相同，而電場消失時，唯有激發態變為He2*較He*濃度大，此外發現一維電漿模型與零維電漿模型在具有相同供給能量下，一維電漿模型能夠產生較高的He激發態物種濃度，能量分佈趨勢與零維電漿模型相同，而電子溫度則與零維模型不同，以He電漿電子溫度最高，而加入氧氣後電子溫度皆比He電漿電子溫度低，但隨著氧氣配比提高He/O2電漿電子溫度也隨之提高。
並列摘要
Abstract In this study, the zero-dimensional and one-dimensional models of He and He/O2 atmospheric plasma were established. The influence of power and oxygen fraction on the plasma characteristics is investigated by the developed model. The main reaction pathway in He and He/O2 atmospheric plasma was realized by the rate-of-production analysis. The zero-dimensional plasma model show that the main species in He atmospheric plasma include metastable helium atoms (He*), metastable dimer molecules (He2*), dimer helium ions (He2+), and electron (e). The power deposition is mainly distributed to elastic collision. In He/O2 plasma, the addition of oxygen significantly reduced metastable species density. Additionally, the main positive ion changes from He2+ to O2+, the main negative charged species changes from electron to O2-, and the power deposition is mainly distributed to the dissociation of oxygen molecules. The electron temperature first decreased then increased when oxygen fraction is increased. The one-dimensional plasma model show that a low frequency (3 kHz) power supply can generate more He metastable species than a high frequency one under the same input power.