小型推力可控混合式火箭推進引擎之研究

Abstract

混合式火箭推進系統的運作機制使其產生之推力可以受到控制，因此設計一組適當的推力控制系統將使混合式火箭推進器的應用更為廣泛。 推力控制系統核心是控制閥，藉由控制閥調整氧化劑的流量可以控制推力。本研究計畫嘗試藉由控制球閥開口大小控制氧化劑流量進行推力控制，並從實驗中求出氧化劑流量與推力關係式，以利未來整合流量回授訊號後可以設計更為精準且穩定的推力控制系統。 本研究探討雙氧水混合式火箭推進器的推力控制系統設計，以高密度聚乙烯 ( HDPE ) 為燃料，注入作為氧化劑濃度90%的雙氧水進行反應。 使用雙氧水為火箭推進系統的氧化劑有許多優點，包括對環境無毒性、成本低、密度高等，配合觸媒分解會產生高溫氧氣的機制更具有自動點火的能力。 使用HDPE為燃料可以降低實驗成本，而材料本身容易加工，亦可以減少準備實驗的工序以及時間。HDPE有適當的燒蝕率，可以提供良好的效率，並同時維持結構的穩定。

Designing an appropriate thrust control system will make the application of hybrid rocket propulsion system more extensive. Control valve is one of the main components in thrust control system. In this work, the relationship between thrust and oxidizer flow rate via the control of a commercial ball valve had ben investigated and verified from several hot fire experiments. The relationship could be the reference to design the more precise and stable close loop throttling system in the future. A 90 % H2O2/ HDPE (High Density Polyethylene) hybrid rocket propulsion system was used in this study. The use of hydrogen peroxide as oxidant of hybrid rocket propulsion system has many advantages, including environment friendly, low cost, high density, and the ability of auto-ignition and re-ignition with the use of MnO2 catalyst which could decompose hydrogen peroxide to oxygen and high temperature. HDPE was chosen as fuel because of several advantages such as low cost, easily to processing, and appropriate regression rate. These properties could cut experiments costs and preparing time, and maintain combustion efficiency and chamber structure.