루프히트파이프 특성연구 = (The) Characteristic study of Loop Heat Pipe

다국어 초록 (Multilingual Abstract)

Recently, heat pipes give examples of successful heat transfer applications of these highly efficient devices in space, energy technology, electronics cooling and so on.
Specially, loop heat pipes(LHPs) are two phase heat transfer devices with capillary pumping of a working fluid. Although LHPs possess all the main advantages of conventional heat pipes, but the special capillary wick structure leads to transfer heat efficiently for distances up to several meters at any orientation in the gravity field. Mainly this heat transfer capability could be possible due to the driving power generated from the capillary wick structure in the evaporator section.
The present study carried out experimental and analytical study of a LHP, employing diverse wicks, various working fluids, different system orientation modes, amount of working fluid and so on. LHP is a two-phase thermal control system using the latent heat of vaporization of an internal working fluid to transfer heat from an evaporator to a condenser. The circulation of the working fluid is accomplished by capillary pressure gradients in fine porosity wick which generated from porous wick structure is in the evaporator. This present LHPs employed multifarious wicks such as rolled single screen of a given mesh size, metal fiber wick and ceramic wick and various working fluid such as Water, R-11, R-22, R-134a and R-717(Ammonia) are used as working fluid. The temperature of cooling media in condenser was maintained by the thermostat. We observed how LHP was affected by diverse wicks, different working fluid, system mode and working fluid amount. Futhermore, we simulated LHP in each various environments. As a result, an important fundamental data required for the establishment of the theoretical prediction of LHP performance was obtained.

목차 (Table of Contents)

• Ⅰ. 서론 1
• 1.1 연구 배경 및 기존 연구 동향 1
• 1.2 연구 내용 및 목적 4
• 1.3 관련 연구 9
• Ⅱ. 연구 이론 12
• 2.1 루프히트파이프의 시동 12
• 2.1.1 루프히트파이프의 구조 및 작동원리 12
• 2.1.2 루프히트파이프의 P-T선도 13
• 2.2 Mathematical Simulation of LHP 17
• 2.2.1 Thermal Module 17
• 2.2.2 Hydrodynamic Module 19
• 2.2.3 Transport Limitations 38
• 2.2.4 Operational Characteristics of Loop Heat Pipe 40
• 2.2.5 Simulated LHP 43
• 2.2.6 Simulation Program 54
• Ⅲ. 실험장치 56
• 3.1 루프히트파이프 윅(Wick) 56
• 3.1.1 Micro Wick Structure 59
• 3.1.2 Porosity and Effective Pore Radius 59
• 3.1.3 Permeability 65
• 3.1.4 Wick Characters 68
• 3.1.4.1 Screen Mesh Wick 68
• 3.1.4.2 Carbon Nano Tube 69
• 3.1.4.3 Metal Form Wick 69
• 3.1.4.4 Metal Fiber Wick 70
• 3.1.4.5 Ceramic Wick 70
• 3.2 Working Fluid of Loop Heat Pipe 74
• 3.2.1 Relationship between Wick and Working Fluid 79
• 3.3. 루프히트파이프 실험장치 81
• 3.3.1. 원통형 증발부를 갖는 루프히트프아프 83
• 3.3.1.1 원통형 증발부를 갖는 루프히트프아프Ⅰ 83
• 3.3.1.2 원통형 증발부를 갖는 루프히트파이프Ⅱ 84
• 3.3.1.3 원통형 증발부를 갖는 루프히트파이프Ⅲ 85
• 3.3.2 작동유체 주입장치 85
• 3.3.3 진공펌프 86
• Ⅳ.실험결과 및 고찰 90
• 4.1. 원통형 증발부를 갖는 루프히트파이프 ( Model : LHPⅠ) 90
• 4.1.1. 혼합 스크린윅을 이용한 최적실험 90
• 4.1.2 히터 위치에 따른 LHP의 영향 96
• 4.1.3 작동유체 주입량 변화 102
• 4.2. 원통형 증발부를 갖는 루프히트파이프 ( Model : LHPⅡ) 104
• 4.2.1 수직모드 104
• 4.2.2 수평모드 105
• 4.2.3 열사이폰(TS) 모드 106
• 4.2.4 작동유체 주입량 변화 107
• 4.3 원통형 증발부를 갖는 루프히트파이프 ( Model : LHPⅢ) 115
• 4.3.1 루프히트파이프 Start Up Procedure 115
• 4.3.2 루프히트파이프 성능 117
• 4.3.3 루프히트파이프 가열면적 122
• 4.3.4 응축부 온도 변화 123
• 4.3.5 모드 실험 126
• 4.3.6 작동유체 주입량 변화 128
• 4.3.7 작동 유체에 따른 LHP의 영향 130
• 4.4 Simulation of LHP 132
• Ⅴ. 결론 142
• 참고문헌 또는 인용문헌 144