표제지
목차
Nomenclatures 7
국문 요약 9
제1장 서론 15
1.1. 연구 대상 15
1.2. 연구 동향 16
1.3. 연구 목적 17
제2장 수치해석 19
제3장 형상변수 변화의 영향 분석 29
3.1. 구조물 높이 변화 효과 29
3.2. 구조물 위치 변화 효과 35
3.3. 공동 폭 변화 효과 39
제4장 계단식 구조물의 영향 분석 43
제5장 난류운동에너지 예측 분석 50
제6장 FFT를 활용한 유동구조 분석 56
제7장 결론 64
References 67
Abstract 72
Table 1-1. Straight Through Labyrinth Seal Geomtrical Parameters. 21
Table 1-2. Advanced Labyrinth Seal Geometrical Parameters. 21
Table 1-3. Boundary Conditions. 21
Figure 2-1. Schematics of straight-through, staggered, stepped labyrinth seals. 20
Figure 2-2. Geometrical parameters of staggered seal, stepped seal. 20
Figure 2-3. Labyrinth seal computational grid in (a) 2D (b) 3D. 23
Figure 2-4. Grid independence test results 28
Figure 2-5. Straight through seal discharge coefficient by turbulence models and comparison... 28
Figure 3-1. Discharge coefficient change by structure height. 30
Figure 3-2. Flow structure change by structure shape. 31
Figure 3-3. Flow structure change by staggered structure height. 33
Figure 3-4. Flow structure chage by stepped structure height. 35
Figure 3-5. Discharge coefficient change by structure position. 36
Figure 3-6. Flow structure change by staggered structure position. 37
Figure 3-7. Flow structure change by stepped structure position. 38
Figure 3-8. Discharge coefficient change by cavity width. 39
Figure 3-9. Flow structure change by cavity width of staggered seal. 40
Figure 3-10. Flow structure change by cavity width of stepped labyrinth seal. 41
Figure 4-1. Straight through and stepped labyrinth seal discharge coefficient prediction using... 43
Figure 4-2. Simulation result for stepped labyrinth seal using (a) k-epsilon model and(b) LES. 45
Figure 4-3. Velocity distributions at stepped labyrinth seal obtained by using k-epsilon model... 46
Figure 4-4. Velocity distributions at stepped labyrinth seal obtained by using LES when (a)... 47
Figure 4-5. Shaft rotation effect comparison at stepped labyrinth seal using k-epsilon model... 48
Figure 4-6. Average tangential velocity obtained by k-epsilon model and LES. 48
Figure 5-1. Turbulence kinetic energy distribution obtained by (a) k-epsilon model, (b) RSM... 51
Figure 5-2. Turbulence kinetic energy at clearance obtained by (a) k-epsilon model, (b)... 52
Figure 5-3. Turbulence kinetic energy prediction by turbulence models (Log scale). 53
Figure 6-1. (a) Vorticity magnitude, (b) 16 Data points selected based on vorticity. 57
Figure 6-2. Discharge coefficient oscillation by shaft rotation state. 58
Figure 6-3. (a) Data points having same frequency turbulence kinetic energy oscillation (b)... 59
Figure 6-4. Position of data points having same frequency with discharge coefficient when... 60
Figure 6-5. (a) Data points having same frequency turbulence kinetic energy oscillation (b)... 61
Figure 6-6. Position of data points having same frequency with discharge coefficient when... 62
Figure 6-7. Time averaged turbulence kinetic energy distribution on (a) shaft stationary state,... 63