3 research outputs found
μ ν ν°λΉ μΊμ€μΌμ΄λμμ ν° ν κ°κ·Ήμ΄ 곡λ ₯μ±λ₯μ λ―ΈμΉλ μν₯
Small turbomachines like turbopumps have relatively large tip clearances due to tolerance limits in manufacturing. However, only a few studies so far have been conducted on this topic and understanding of large tip clearance impact on turbine blade performance is lacking. Based on Lee [1]s experiment, this research presents numerical study about the large tip clearance in a turbine cascade. Tip clearance varies from 1% to 20% based on the blade chord like experiment and CFD simulation was validated by comparison with Lee [1]s experiment. This research focused on variation of aerodynamic loss for large tip clearance in detail.
Overall loss at downstream increased up to 10% tip clearance and then decreased over 10% tip clearance. Decreasing overall loss for large tip clearance is different result from previous researches for small tip clearances. From the breakdown of the overall loss, it was found that variations of tip leakage loss and secondary loss were the main reason of the decreasing overall loss for large tip clearance. Thus, by detailed investigation about tip leakage loss and secondary loss, this research explains the reason of decreasing overall loss at downstream for large tip clearance. Even though the overall loss at downstream decreased for large tip clearance, stream-thrust averaged loss increased continuously with increasing tip clearance. The reason of continuously increasing stream-thrust averaged loss was also explained in this research.ν°λ³΄ννμ κ°μ μνν°λ³΄κΈ°κ³λ μ 쑰곡μ μ 곡차μ νκ³λ‘ μΈν΄ μλμ μΌλ‘ ν° ν κ°κ·Ή(10%~)μ κ°μ§λ€. νμ§λ§ μμ ν κ°κ·Ήκ³Ό λ¬λ¦¬ ν° ν κ°κ·Ήμ λν΄ μ§κΈκΉμ§ λ§μ μ°κ΅¬κ° μνλμ§ μμλ€. μ΄ λ
Όλ¬Έμ μ΄ν¨μ± [1]μ μ€νμ λ°νμΌλ‘ CFD ν΄μμ νμκ³ , ν° ν κ°κ·Ήμμ 곡λ ₯μμ€μ λ³νμ λν΄ μμΈν μ΄ν΄λ³΄μλ€. νλ₯μμμ μ 체 곡λ ₯μμ€μ ν κ°κ·Ή λΉμ¨ 10% κΉμ§ μ¦κ°λ₯Ό νλ€κ° 10% μ΄μμμλ κ°μνλ κ²½ν₯μ 보μ¬μ€λ€. νλ₯μμμ μ 체 곡λ ₯μμ€μ λΆν΄ν΄λ³Έ κ²°κ³Ό, tip leakage loss μ secondary loss μ λ³νκ° ν° ν κ°κ·Ήμμμ μ 체 μμ€ λ³νμ μ£Ό μμΈμμ νμΈνμλ€. μ΄ λ
Όλ¬Έμ ν° ν κ°κ·Ήμμμ tip leakage loss μ secondary lossμ λ³ν μμΈμ CFD ν΄μμ ν΅ν΄ μμΈν λΆμνμλ€. λΉλ‘ νλ₯μμμ μ 체 μμ€μ 10% μ΄μμ ν° ν κ°κ·Ήμμ κ°μνμ§λ§, stream-thrust averaged loss λ μ€νλ € ν κ°κ·Ήμ΄ μ¦κ°ν¨μ λ°λΌ κ³μμ μΌλ‘ μ¦κ°νλ λͺ¨μ΅μ 보μ¬μ£Όμκ³ , μ΄μ λν μμΈκ³Ό μ΄κ²μ μλ―Έμ λν΄μλ μ΄ λ
Όλ¬Έμμ μμΈν λ€λ£¨μλ€.Chapter 1 Introduction 1
1.1 General description of problem 1
1.2 Previous researches 2
1.2.1 Flow field 2
1.2.2 Blade loading 4
1.2.3 Aerodynamic loss 4
1.2.4 Large tip clearance 6
Chapter 2 CFD Simulation 8
2.1 Simulation setup 8
2.1.1 Calculation code 8
2.1.2 Boundary condition 9
2.1.3 Mesh grid 9
2.2 CFD validation 12
Chapter 3 Aerodynamic Loss 18
3.1 Overall loss 18
3.2 Tip leakage loss 21
3.3 Secondary loss 29
Chapter 4 Stream-thrust Averaged Loss 33
4.1 Unturned flow 33
4.2 Stream-thrust averaged loss 36
Chapter 5 Conclusions 39
Reference 41
Abstract 44Maste
(A)Study on punching of ultra small size hole array
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Όλ¬Έ(μμ¬)--μμΈλνκ΅ λνμ :κΈ°κ³ν곡곡νλΆ,2005.Maste