碩士生: 楊宗穎
畢業年分: 2025年2月
論文名稱: 固體推進劑中混參鐵粉對脈衝式電漿推進器整體性能的影響(中文) / Effect of iron powder blending in solide propellant on the overall performance of pulsed plasma thruster (英文)
中文摘要:
脈衝電漿推進器（PPT）因其小型化、簡單性及精確推力生成能力，廣泛應用於立方衛星。然而，其低效率及推力功率比限制了更廣泛的採用。本研究提出一種新型 PMMA 金屬複合聚合物推進劑（PMMA@Fe），以摻雜鐵粉作為替代傳統 PTFE 推進劑的方案。合成並評估了鐵粉濃度範圍為 5 wt% 至 20 wt% 的 PMMA@Fe 樣品。結果顯示，鐵粉的添加降低了電漿阻抗並提高放電電流，相較於純 PMMA，其脈衝推力（impulse bit）提升了 62.5%（從 80.3 μNs 增至 131.9 μNs），推力功率比提升了 63.5%（從 17.8 μN/J 增至 29.3 μN/J）。 材料分析顯示，PMMA的燒蝕速率從純 PMMA 的 4.5 μg/shot 增至 PMMA@5 wt% Fe 的 8.1 μg/shot，並在更高濃度下趨於平穩。電漿羽流分析表明，隨著鐵含量增加，電漿生成量增幅達 50%，PMMA 分解物的光學發射強度提高了 40%。儘管性能有所提升，但高鐵含量（≥20 wt%）導致不規則放電及碳和金屬沉積，限制了推進器的使用壽命至 6000 次放電。本研究結果顯示PMMA@15 wt%Fe 為最佳配方，達到 19.6% 的推力效率及 1,426 s 的比衝，同時保持結構完整性。這些研究結果表明，PMMA@Fe 在提升 PPT 效能方面具有顯著潛力，可有效應對立方衛星應用中的效率及耐久性挑戰。
英文摘要:
Pulsed plasma thruster (PPT) is extensively utilized in CubeSats due to their compact size, simplicity, and precise thrust generation capabilities. However, their limited efficiency and thrust-to-power ratio constrain broader adoption. This study presents a novel PMMA-based metal-composite polymer propellant (PMMA@Fe) doped with iron powder as an alternative to conventional PTFE propellants. PMMA@Fe samples with iron powder concentrations ranging from 5 wt% to 20 wt% were synthesized and evaluated. Results show that the addition of iron powder reduced plasma impedance and increased discharge currents, leading to a 62.5% improvement in impulse bit (from 80.3 μNs to 131.9 μNs) and a 63.5% increase in the thrust-to-power ratio (from 17.8 μN/J to 29.3 μN/J) compared to pure PMMA.
Material analysis revealed an increase in the ablation rate from 4.5 μg/shot (pure PMMA) to 8.1 μg/shot (5 wt% Fe), plateauing at higher concentrations. Plasma plume analysis indicated a 50% rise in plasma generation and a 40% enhancement in optical emission intensity with increasing iron content. Despite these performance improvements, higher iron concentrations (≥20 wt%) caused irregular discharges and carbon-metal deposition, limiting the thruster lifespan to 6,000 discharges.
The optimal composition was identified as PMMA@15 wt%Fe, achieving 19.6% thrust efficiency and a specific impulse of 1,426 s while maintaining structural integrity. These findings demonstrate the potential of PMMA@Fe to significantly enhance PPT performance, addressing the challenges of efficiency and durability for CubeSat applications.
