加壓劑 吐出時 溫度降下와 熱傳達 特性에 關한 硏究 = Temperature Drop and Heat Transfer Characteristics during Pressurant Discharging

다국어 초록 (Multilingual Abstract)

The thermal characteristics of pressurant such as gaseous nitrogen or helium in the on-board storage tank, which is essential for designing propellant pressurization system of liquid-propellant launch vehicle, were studied. Experiments were performed in order to measure the rate of temperature drop while pressure in a pressurant tank changes. The results of experiments were compared with calculation results from the case with the influence of heat transfer among pressurant, tank shell, and surrounding fluid and calculation results from the case without the influence of heat transfer. Analytic solutions were in good agreement with the results from pressurant discharge tests. In the following, the results obtained from this study are summarized:
1. With gaseous nitrogen or helium at room temperature condition as pressurant (The external fluid of pressurant storage tank is air.), the rate of temperature drop according to the rate of pressure drop in a pressurant storage tank decreases as shown in the following empirical relations:
◁수식 삽입▷(원문을 참조하세요)
2. With gaseous helium at cryogenic temperature condition as pressurant (The external fluid of pressurant storage tank is liquid oxygen.), the rate of temperature drop according to the rate of pressure drop in a pressurant storage tank decreases as shown in the following empirical relation:
◁수식 삽입▷(원문을 참조하세요)
3. When the pressurant is changed into the constant volume, the pressurant storage tank under cryogenic (90K) condition could hold the pressurant about 2.7 times more than the pressurant storage tank under room temperature (300K) condition.
4. Without the consideration of heat transfer among pressurant, tank shell, and external fluid during pressurant discharge, the differences of temperature trends between the results from analytic calculation and the experimental results were about 300% and 150% at the room temperature condition and cryogenic temperature condition respectively.
5. In the case of air as external fluid, the convection heat transfer coefficient inside pressurant tank was dominant compared to the convection heat transfer coefficient between external fluid. However, in the case of liquid oxygen as external fluid, both convection heat transfer coefficients inside and outside pressurant storage tank should be under consideration. Therefore incoming energy was considerably different according to external fluid.

목차 (Table of Contents)

• 제1장 서론 1
• 1.1 연구 배경 1
• 1.2 연구 동향 6
• 1.3 연구 내용 및 방법 10
• 제2장 이론적 고찰 13
• 2.1 유체 유동 열역학 13
• 2.1.1 연속방정식 13
• 2.1.2 밀폐시스템에서의 제 1법칙 16
• 2.1.3 개방시스템에서의 제 1법칙 16
• 2.1.4 이상기체 상태방정식 17
• 2.1.5 실제기체 상태방정식 17
• 2.1.6 이상기체의 비열 18
• 2.1.7 등엔트로피 유동 19
• 2.2 가압제 토출시 지배방정식 및 열전달 20
• 2.2.1 검사체적에 대한 질량 보존 21
• 2.2.2 검사체적에 대한 에너지 보존 22
• 2.2.3 열전달이 없는 경우 24
• 2.2.4 열전달이 있는 경우 26
• 제3장 실험장치 및 방법 35
• 3.1 실험장치 35
• 3.1.1 가압제 용기 35
• 3.1.2 1차 감압제어 36
• 3.1.3 2차 감압제어 40
• 3.1.4 얼리지 시뮬레이션 장치 42
• 3.1.5 기타 지원 설비 45
• 3.1.6 제어 및 계측 시스템 47
• 3.2 실험방법 56
• 제4장 결과 및 고찰 60
• 4.1 결과의 처리방법 60
• 4.2 해석 결과 61
• 4.3 실험 결과 65
• 4.3.1 가압시스템 65
• 4.3.2 Test-1 조건에서의 열특성 67
• 4.3.3 Test-2 조건에서의 열특성 71
• 4.3.4 Test-3 조건에서의 열특성 74
• 4.3.5 Test-4 조건에서의 열특성 77
• 4.3.6 Test-5 조건에서의 열특성 79
• 4.3.7 Test-6 조건에서의 열특성 81
• 4.3.8 Test-7 조건에서의 열특성 83
• 4.3.9 Test-8 조건에서의 열특성 84
• 4.3.10 Test-9와 Test-10 조건에서의 열특성 86
• 제5장 결론 125
• 참고문헌 128
• ABSTRACT 133