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제출문

보고서 초록

요약문

SUMMARY

CONTENTS

목차

제1장 서론 28

제1절 연구개발의 필요성 28

제2절 국내외 기술개발 현황 30

제3절 연구개발 목표 및 연구 내용 33

제2장 세관에서 고온 고압 헬륨의 열유동 해석 34

제1절 서론 34

1. 연구 배경 34

2. 연구 목적 36

제2절 선행연구 고찰 36

1. 서론 36

2. 유동 특성에 관한 연구 37

3. 지배 방정식 39

4. 난류 모델 40

5. 물성치 변화에 대한 영향 41

제3절 수평관내 물성치 변화를 고려한 난류유동 46

1. 물성치가 일정한 강제대류 유동해석 46

2. 물성치 변화를 고려한 강제대류 유동해석 48

제4절 PCHE 관내 유동의 열전달 예측 65

1. 서론 65

2. 격자 구성과 경계조건 65

3. 수치 기법 66

4. 계산 결과 66

제5절 결론 71

제3장 세관에서 고온 고압 헬륨의 열유동에 관한 실험적 연구 72

제1절 서론 72

1. 연구 배경 72

2. 연구 목적 73

제2절 선행연구 고찰 75

1. 서론 75

2. 관내에서의 유동 75

3. 관내에서의 대류 열전달 78

4. 재층류화 80

5. 물성치 변화에 대한 영향 81

6. 선행연구 고찰 요약 82

제3절 실험장치 및 실험방법 96

1. 실험장치 96

2. 실험방법 99

3. 데이터 처리 100

4. 실험오차 분석 101

제4절 실험결과 및 고찰 114

1. 실험 조건 114

2. 열전달 계수 114

3. 압력강화 116

제5절 결론 122

제4장 세관 내 물의 대류비등 시 압력의 영향에 관한 실험적 연구 124

제1절 서론 124

1. 연구 배경 124

2. 연구 목적 124

제2절 선행연구 고찰 125

1. 서론 125

2. 대류비등 열전달 126

3. 미니채널에서의 대류비등 열전달 129

제3절 실험장치 및 실험방법 148

1. 실험장치 148

2. 실험방법 152

3. 데이터 처리 153

4. 실험오차 분석 155

제4절 실험결과 및 고찰 169

1. 단상유동 실험 169

2. 대류비등 실험 169

3. 대류비등 실험결과 170

제5절 결론 177

제5장 결론 및 향후 계획 178

참고문헌 182

Table 2.2.1. Turbulent forced convection correlation through a circular ducts with constant properties (Nu) 42

Table 2.2.2. Exponents n and m for turbulen forced convection through circular ducts 43

Table 2.2.3. Turbulent forced convection correlation in circular duct for gases with variable properties 44

Table 2.3.1. simulated conditions 51

Table 2.3.2. Helium gas properties (35기압, 200 K＜T＜1500 K) 51

Table 2.3.3. Pure Nickel properties (200 K＜T＜1500 K) 51

Table 2.3.4. Selected NIST Data 52

Table 2.3.5. Comparison of prediction of Fluent by previous correlations 53

Table 3.2.1. Turbulent forced friction factor correlations for smooth circular ducts 83

Table 3.2.2. Turbulent forced convection correlations through a circular ducts with constant properties(Nu) 84

Table 3.2.3. Exponents n and m for turbulent forced convection through circular ducts 85

Table 3.2.4. Turbulent forced convection correlation in circular duct for gases with variable properties 86

Table 3.2.5. Past work of high temperature compact heat exchangers 88

Table 3.3.1. Use, Property, and element of Inconels 104

Table 4.2.1. Summery of past work on flow boiling in minichannels 138

Table 4.2.2. Flow boiling heat transfer correlations for minichannels 141

Table 4.2.3. Two-phase pressure drop correlations for minichannels 142

Table 4.3.1. Major components of experimental apparatus 158

Table 4.3.2. Dimensions of the test tube 159

Table 4.3.3. Measurement error 159

Fig. 1.1.1. Intermediate Heat Transport Loop of VHTR 29

Fig. 1.1.2. Hydraulic Diameter Scale of Compact heat Exchangers 29

Fig. 1.1.3. Channel Size Classification of Heat Exchangers 30

Fig. 1.2.1. Printed Circuit Heat Exchanger (Heatrix co.) 32

Fig. 2.1.1. Sulfur-Iodine(SI) cycle process 35

Fig. 2.3.1. The schematic diagram of circular channel flow 53

Fig. 2.3.2. The grid - 2D 54

Fig. 2.3.3. In case of constant property, the results of prediction for Nusselt number 54

Fig. 2.3.4. Density profiles of helium versus temperature 55

Fig. 2.3.5. Specific heat profiles of helium versus temperature 55

Fig. 2.3.6. Thermal conductivity profiles of helium versus temperature 56

Fig. 2.3.7. Viscosity profiles of helium versus temperature 56

Fig. 2.3.8. Thermal conductivity profiles of pure Nickel versus temperature 57

Fig. 2.3.9. Specific heat profiles of pure Nickel versus temperature -1 57

Fig. 2.3.9. Specific heat profiles of pure Nickel versus temperature -2 58

Fig. 2.3.10. Temperature profiles at the wall 58

Fig. 2.3.11. The results of prediction for Nusselt number 59

Fig. 2.3.12. Plots of heat transfer coefficient versus distance along the tube length 59

Fig. 2.3.13. In case of high mass flux, the results of prediction for heat transfer coefficient 60

Fig. 2.3.14. In case of low mass flux, the results of prediction for heat transfer coefficient 60

Fig. 2.3.15. The profiles of Nusselt number versus Reynolds number(Circle) - NIST #60 61

Fig. 2.3.16. The ratio of Nusselt number versus Reynolds number(circle) 61

Fig. 2.3.17. The profiles of Nusselt number versus Reynolds number(square) 62

Fig. 2.3.18. The ratio of Nusselt number versus Reynolds number(square) 62

Fig. 2.3.19. The profiles of Nusselt number versus Reynolds number(circle)-NIST #66 63

Fig. 2.3.20. The ratio of Nusselt number versus Reynolds number(circle) 63

Fig. 2.3.21. The profiles of Nusselt number versus Reynolds number(circle, square) 64

Fig. 2.3.22. The profiles of heat transfer coefficient at the first cell 64

Fig. 2.4.1. Construction of PCHEs 67

Fig. 2.4.2. The grid of PCHE - 3D 67

Fig. 2.4.3. Boundary conditions 68

Fig. 2.4.4. The profile of temperature (Θ ＝ 0˚) 68

Fig. 2.4.5. The profile of temperature (Θ ＝ 115˚) 69

Fig. 2.4.6. The profile of temperature (Θ ＝ 100˚) 69

Fig. 2.4.7. The profiles of j factor versus Reynolds number (angle) 70

Fig. 2.4.8. The profiles of j factor versus Reynolds number (temperature) 70

Fig. 3.1.1. Schematic of Iodine-Sulfur process 74

Fig. 3.1.2. PCHE (Printed Circuit Heat Exchanger) 74

Fig. 3.2.1. Laminar flow in circular duct 89

Fig. 3.2.2. Turbulent flow in circular duct 89

Fig. 3.2.3. Turbulent forced friction factor correlations for smooth circular ducts 89

Fig. 3.2.4. Moody diagram 90

Fig. 3.2.5. Friction factor vs Reynolds number (Olsson and Sunden, 1995) 90

Fig. 3.2.6. Friction factor vs Reynolds number (Hwang et. al., 2003) 91

Fig. 3.2.7. Friction factor vs Reynolds number (Son and Park, 2005) 91

Fig. 3.2.8. Schematic of experimental apparatus (Olsson and Glover, 1995) 92

Fig. 3.2.9. Nusselt number vs Reynolds number (Olsson and Glover, 1995) 92

Fig. 3.2.10. Heat transfer coefficient in low mass flux (Nam, 2006) 93

Fig. 3.2.11. Heat transfer coefficient in high mass flux (Nam, 2006) 93

Fig. 3.2.12/3.2.11. Property of air and helium at 60 bar 94

Fig. 3.3.1. Definition of minichannel 106

Fig. 3.3.2. Schematic diagram of experimental apparatus 106

Fig. 3.3.3. Photograph of experimental apparatus 107

Fig. 3.3.4. 1000-h Rupture stress of Inconels 107

Fig. 3.3.5. Schematic diagram of the preheater 108

Fig. 3.3.6. Photograph of preheater 108

Fig. 3.3.7. Photograph of the test section 109

Fig. 3.3.8. Schematic diagram of test section 110

Fig. 3.3.9. Photograph of pressure drop transmitter 111

Fig. 3.3.10. Photograph of gas booster 111

Fig. 3.3.11. Photograph of cooler 112

Fig. 3.3.12. Photograph of flowmeter 112

Fig. 3.3.13. Average error of thermocouple 113

Fig. 3.3.14. Thermocouple signal 113

Fig. 3.3.15. Mass flow rate error vs Time 114

Fig. 3.4.1. Comparison of correlations 118

Fig. 3.4.2. Nu vs Reynolds number 118

Fig. 3.4.3. Nu vs x* 119

Fig. 3.4.4. Nusselt number at 100℃ 119

Fig. 3.4.5. Nusselt number at 400℃ 120

Fig. 3.4.6. Nu vs Heat flux 120

Fig. 3.4.7. Pressure drop vs. Reynolds number 121

Fig. 3.4.8. friction factor vs. Reynolds number 121

Fig. 4.2.1. Heat transfer coefficient as a function of vapor quality (Lazarek et al., 1982) 143

Fig. 4.2.2. Heat transfer coefficients at constant heat flux (Wambsganss, 1993) 143

Fig. 4.2.3. Nu vs. quality (Kureta et al., 1998) 144

Fig. 4.2.4. Heat transfer coefficient vs. quality (Bao et al., 2000) 144

Fig. 4.2.5. Heat transfer coefficient v.s. quality (Lin et al., 2001) 145

Fig. 4.2.6. Heat transfer coefficient v.s. quality (Choo & Bang, 2004) 145

Fig. 4.2.7. Heat transfer coefficient v.s. quality (Cortina et al., 2004) 146

Fig. 4.2.8. Heat transfer coefficient v.s. quality (Huo et al., 2004) 146

Fig. 4.2.9. Heat transfer coefficient v.s. quality (Wang & Chen, 2005) 147

Fig. 4.2.10. Heat transfer coefficient v.s. quality 147

Fig. 4.2.11. Pressure drop v.s. quality 148

Fig. 4.3.1. Schematic diagram of experimental apparatus 160

Fig. 4.3.2. Photograph of experimental apparatus 160

Fig. 4.3.3. Numerical analysis of the axial conduction on the 316 SS tube wall 161

Fig. 4.3.4. Photograph of magnetic gear pump 161

Fig. 4.3.5. Photograph of flow meter 162

Fig. 4.3.6. Photograph of evaporator 162

Fig. 4.3.7. Schematic diagram of evaporator 163

Fig. 4.3.8. Schematic diagram of test section 163

Fig. 4.3.9. Schematic diagram of dielectric section 164

Fig. 4.3.10. Photograph of test tube 164

Fig. 4.3.11. Photograph of Power supply 164

Fig. 4.3.12. Photograph of pressure drop transmitter 165

Fig. 4.3.13. Schematic diagram of thermocouple position 165

Fig. 4.3.14. Photograph of thermocouple attachment work 166

Fig. 4.3.15. Photograph of constant temp. bath 166

Fig. 4.3.16. Photograph of Pressurizer 167

Fig. 4.3.17. Photograph of Data acquisition system 167

Fig. 4.3.18. Average error of thermocouple on the wall 168

Fig. 4.3.19. Mass flow rate error v.s. Time 168

Fig. 4.4.1. Nu number V.S. x* 172

Fig. 4.4.2. Friction factor V.S Re number 173

Fig. 4.4.3. Effect of heat flux and mass quality on heat transfer coefficient 173

Fig. 4.4.4. Effect of operating pressure on heat transfer cofficient 174

Fig. 4.4.5. Comparison of experimental data with previous correlation (1 bar) 174

Fig. 4.4.6. Comparison of experimental data with previous correlation (18 bar) 175

Fig. 4.4.7. Effect of operating pressure on pressure drop 175

Fig. 4.4.8. Comparison of experimental data with previous correlation (1 bar) 176

Fig. 4.4.9. Comparison of experimental data with previous correlation (18 bar) 176