표제지

목차

기호 설명 14

제1장 서론 16

1.1. 연구 배경 16

1.2. 기존 연구 20

1.3. 연구 목적 및 내용 25

제2장 이론적 배경 29

2.1. 후류 모델 29

2.2. 대기 경계층 및 윈드 쉬어 32

2.3. 년간 발전량 및 발전단지 효율 35

제3장 2 MW 풍력터빈 설계 및 모델링 38

3.1. 2 MW 풍력터빈 설계 및 모델링 38

제4장 풍력발전단지 모델링 및 전산유체해석 45

4.1. 풍력발전단지 모델링 45

4.1.1. 4 MW 풍력발전단지 45

4.1.2. 6 MW 풍력발전단지 49

4.2. 4 MW 풍력발전단지 전산유체해석 53

4.2.1. 격자 53

4.2.2. 경계 조건 58

4.2.3. 난류 모델 63

4.2.4. 결과 고찰 64

4.3. 6 MW 풍력발전단지 전산유체해석 95

4.3.1. 격자 95

4.3.2. 경계 조건 99

4.3.3. 결과 고찰 102

4.4. 풍력발전단지 효율 132

4.5. 축소 풍력발전단지 제언 138

제5장 결론 140

참고문헌 142

Abstract 147

Table 2.1. Typical power law exponents for varying terrain. 33

Table 3.1. General specifications of 2 MW wind turbine. 40

Table 3.2. Detailed specifications of 2 MW wind turbine blade. 41

Table 4.1. Separation distance according to CFD analysis cases for 4 MW wind farm. 46

Table 4.2. Separation distance according to CFD analysis cases for 6 MW wind farm. 50

Table 4.3. Mesh information of rotational region and stationary region for 4 MW wind farm. 55

Table 4.4. Boundary conditions for 4 MW wind farm. 60

Table 4.5. CFD results according to the separation distance for 4 MW wind farm. 67

Table 4.6. Mesh information of rotational region and stationary region for 6 MW wind farm. 96

Table 4.7. Boundary conditions for 6 MW wind farm. 100

Table 4.8. CFD results according to the separation distance for 6 MW wind farm. 105

Table 4.9. Aerodynamic power output based on wake model. 134

Fig. 1.1. Wake of Horns Rev wind farm in Denmark. 18

Fig. 1.2. Various wind farm layout concept. 19

Fig. 1.3. Evolution of the wind speed field in wake. 22

Fig. 1.4. Optimum tower spacing in wind farms in flat terrain and uniform crossover operator in genetic algorithm. 23

Fig. 1.5. Turbine affected by the wake of other turbines. 24

Fig. 1.6. Actuator disc model for CFD analysis. 28

Fig. 2.1. Schematic view of wake effect. 31

Fig. 2.2. Atmospheric boundary layer. 34

Fig. 2.3. Typical Weibull distribution for various shape factor k with wind speed of 11 ㎧. 37

Fig. 3.1. Airfoils for 2 MW wind turbine blade 42

Fig. 3.2. 2 MW wind turbine blade 43

Fig. 3.3. 2 MW wind turbine 44

Fig. 4.1. 4 MW wind farm layout. 47

Fig. 4.2. Wind turbine identification and separation distance for 4 MW wind farm. 48

Fig. 4.3. 6 MW wind farm layout. 51

Fig. 4.4. Wind turbine identification and separation distance for 6 MW wind farm. 52

Fig. 4.5. Rotational region mesh for 4 MW wind farm 56

Fig. 4.6. Stationary region mesh for 4 MW wind farm. 57

Fig. 4.7. Regions of boundary conditions for 4 MW wind farm. 61

Fig. 4.8. Calculated inlet wind speed according to the height with wind shear. 62

Fig. 4.9. Aerodynamic power output and power output ratio according to the separation distance for 4 MW wind farm 68

Fig. 4.10. Wake region expressed by rotor diameter D. 69

Fig. 4.11. Axial direction wind speed at reference height for case no. 1 of L2 with 3D for 4 MW wind farm. 70

Fig. 4.12. Axial direction wind speed at reference height for case no. 2 of L2 with 4D for 4 MW wind farm. 71

Fig. 4.13. Axial direction wind speed at reference height for case no. 3 of L2 with 5D for 4 MW wind farm. 72

Fig. 4.14. Axial direction wind speed at reference height for case no. 4 of L2 with 6D for 4 MW wind farm. 73

Fig. 4.15. Axial direction wind speed at reference height for case no. 5 of L2 with 7D for 4 MW wind farm. 74

Fig. 4.16. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 1 of L2 with 3D for 4 MW wind farm 75

Fig. 4.17. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 2 of L2 with 4D for 4 MW wind farm 76

Fig. 4.18. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 3 of L2 with 5D for 4 MW wind farm 77

Fig. 4.19. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 4 of L2 with 6D for 4 MW wind farm 78

Fig. 4.20. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 5 of L2 with 7D for 4 MW wind farm 79

Fig. 4.21. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 1 of L2 with 3D for 4 MW wind farm. 80

Fig. 4.22. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 2 of L2 with 4D for 4 MW wind farm. 81

Fig. 4.23. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 3 of L2 with 5D for 4 MW wind farm. 82

Fig. 4.24. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 4 of L2 with 6D for 4 MW wind farm. 83

Fig. 4.25. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 5 of L2 with 7D for 4 MW wind farm. 84

Fig. 4.26. Pressure coefficient of blade 1 for case no. 1 of L2 with 3D for 4 MW wind farm 85

Fig. 4.27. Pressure coefficient of blade 1 for case no. 2 of L2 with 4D for 4 MW wind farm 86

Fig. 4.28. Pressure coefficient of blade 1 for case no. 3 of L2 with 5D for 4 MW wind farm 87

Fig. 4.29. Pressure coefficient of blade 1 for case no. 4 of L2 with 6D for 4 MW wind farm 88

Fig. 4.30. Pressure coefficient of blade 1 for case no. 5 of L2 with 7D for 4 MW wind farm 89

Fig. 4.31. Turbulence intermittency of blade 1 for case no. 1 of L2 with 3D for 4 MW wind farm; blue-laminar dominant, red-turbulent dominant. 90

Fig. 4.32. Turbulence intermittency of blade 1 for case no. 2 of L2 with 4D for 4 MW wind farm; blue-laminar dominant, red-turbulent dominant. 91

Fig. 4.33. Turbulence intermittency of blade 1 for case no. 3 of L2 with 5D for 4 MW wind farm; blue-laminar dominant, red-turbulent dominant. 92

Fig. 4.34. Turbulence intermittency of blade 1 for case no. 4 of L2 with 6D for 4 MW wind farm; blue-laminar dominant, red-turbulent dominant. 93

Fig. 4.35. Turbulence intermittency of blade 1 for case no. 5 of L2 with 7D for 4 MW wind farm; blue-laminar dominant, red-turbulent dominant. 94

Fig. 4.36. Rotational region mesh for 6 MW wind farm 97

Fig. 4.37. Stationary region mesh for 6 MW wind farm. 98

Fig. 4.38. Regions of boundary conditions for 6 MW wind farm. 101

Fig. 4.39. Aerodynamic power output and power output ratio according to the separation distance for 6 MW wind farm 106

Fig. 4.40. Axial direction wind speed at reference height for case no. 1 of L2 with 3D for 6 MW wind farm. 107

Fig. 4.41. Axial direction wind speed at reference height for case no. 2 of L2 with 4D for 6 MW wind farm. 108

Fig. 4.42. Axial direction wind speed at reference height for case no. 3 of L2 with 5D for 6 MW wind farm. 109

Fig. 4.43. Axial direction wind speed at reference height for case no. 4 of L2 with 6D for 6 MW wind farm. 110

Fig. 4.44. Axial direction wind speed at reference height for case no. 5 of L2 with 7D for 6 MW wind farm. 111

Fig. 4.45. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 1 of L2 with 3D for 6 MW wind farm 112

Fig. 4.46. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 2 of L2 with 4D for 6 MW wind farm 113

Fig. 4.47. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 3 of L2 with 5D for 6 MW wind farm 114

Fig. 4.48. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 4 of L2 with 6D for 6 MW wind farm 115

Fig. 4.49. Axial direction wind speed and pressure change with respect to the reference height of center plane for case no. 5 of L2 with 7D for 6 MW wind farm 116

Fig. 4.50. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 1 of L2 with 3D for 6 MW wind farm. 117

Fig. 4.51. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 2 of L2 with 4D for 6 MW wind farm. 118

Fig. 4.52. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 3 of L2 with 5D for 6 MW wind farm. 119

Fig. 4.53. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 4 of L2 with 6D for 6 MW wind farm. 120

Fig. 4.54. Axial direction wind speed profile according to the height with the reference position of wind turbine WT1 at the center plane for case no. 5 of L2 with 7D for 6 MW wind farm. 121

Fig. 4.55. Pressure coefficient of blade 1 for case no. 1 of L2 with 3D for 6 MW wind farm 122

Fig. 4.56. Pressure coefficient of blade 1 for case no. 2 of L2 with 4D for 6 MW wind farm 123

Fig. 4.57. Pressure coefficient of blade 1 for case no. 3 of L2 with 5D for 6 MW wind farm 124

Fig. 4.58. Pressure coefficient of blade 1 for case no. 4 of L2 with 6D for 6 MW wind farm 125

Fig. 4.59. Pressure coefficient of blade 1 for case no. 5 of L2 with 7D for 6 MW wind farm 126

Fig. 4.60. Turbulence intermittency of blade 1 for case no. 1 of L2 with 3D for 6 MW wind farm; blue-laminar dominant, red-turbulent dominant. 127

Fig. 4.61. Turbulence intermittency of blade 1 for case no. 2 of L2 with 4D for 6 MW wind farm; blue-laminar dominant, red-turbulent dominant. 128

Fig. 4.62. Turbulence intermittency of blade 1 for case no. 3 of L2 with 5D for 6 MW wind farm; blue-laminar dominant, red-turbulent dominant. 129

Fig. 4.63. Turbulence intermittency of blade 1 for case no. 4 of L2 with 6D for 6 MW wind farm; blue-laminar dominant, red-turbulent dominant. 130

Fig. 4.64. Turbulence intermittency of blade 1 for case no. 5 of L2 with 7D for 6 MW wind farm; blue-laminar dominant, red-turbulent dominant. 131

Fig. 4.65. Axial direction incoming wind speed to wind turbine WT2 and WT3 based on wake model. 135

Fig. 4.66. Aerodynamic power output of wind turbines. 136

Fig. 4.67. Wind farm efficiency for 4 MW, 6 MW and wake model. 137

Fig. 4.68. Scale wind farm configuration. 139

 This study presents aerodynamic power outputs of wind turbines for 4 MW and 6 MW wind farm composed of 2 MW wind turbine according to the turbine separation distance by using CFD. CFD has some limitation to meet non-dimensional wall distance and no. of mesh and mesh quality concurrently. But it is most recommendable method to research wind farm aerodynamics because real or scale experiments including wind tunnel test are actually impossible due to the scale effect and wall effect. This study has a meaning by applying CFD to real scale wind turbines of wind farm to evaluate aerodynamics power output change according to the separation distance change. For each wind turbine rotor, not actuator disc model with momentum source but full 3-dimensional model with wind shear is used for CFD analysis. Aerodynamic power out comparison between wake model and CFD results is carried out. There is an aerodynamic power output loss for downstream wind turbine due to the wake from upstream wind turbine. The aerodynamic power output of downstream wind turbine increases as turbine separation distance increases. Aerodynamic power output increasing ratio is different with respect to the separation distance of five times of rotor diameter. Within separation distance of five times of rotor diameter, aerodynamic power output recovers quickly as separation distance increase. For the separation distance over five times of rotor diameter, aerodynamic power output recovers slowly as separation distance increases. So separation distance of five times of rotor diameter is basis for the wind farm layout design. Wind farm layout design especially for the offshore wind farm is a key factor for the initial investment cost, annual energy production and maintenance cost. The results of this study can be applied to the wind farm layout design effectively.