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Experimental Study on Unsteady Kinematics of Shrouded Multistage Axial Compressor Flow : 다단 슈라우드형 축류 압축기 유동의 비정상 운동학에 대한 실험적 연구
DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | 송성진 | - |
dc.contributor.author | Jaehyoung Lee | - |
dc.date.accessioned | 2019-10-21T01:46:34Z | - |
dc.date.available | 2019-10-21T01:46:34Z | - |
dc.date.issued | 2019-08 | - |
dc.identifier.other | 000000156553 | - |
dc.identifier.uri | https://hdl.handle.net/10371/161899 | - |
dc.identifier.uri | http://dcollection.snu.ac.kr/common/orgView/000000156553 | ko_KR |
dc.description | 학위논문(박사)--서울대학교 대학원 :공과대학 기계항공공학부,2019. 8. 송성진. | - |
dc.description.abstract | An experimental investigation has been conducted to identify the unsteady kinematics of shrouded stator of a low-speed multistage axial compressor. Unsteady velocity distributions have been measured at upstream and downstream of 3rd shrouded stator using single-element 45° slanted hot-wires. The data have been ensemble-averaged to obtain the timewise variation of velocity vectors upstream and downstream of the shrouded 3rd stator.
The width and velocity disturbances of 3rd stator wake varied by the merge with 3rd rotor wakes. Between the two 3rd rotor wakes, a pseudo-wake region is observed, which is presumed to be created by the recirculation due to the negative jet of the 3rd rotor wakes. This velocity disturbance is attenuated by the viscous mixing and wake stretching as the 3rd wakes are transported downstream. Because of the velocity disturbances, the aerodynamic properties downstream of the stator blade vary. The hubside corner separation of the multistage shrouded stator alters the unsteady kinematics of the hubside shrouded stator flow. The attenuation of the wake is lower at the hubside due to the reduced effective passage width by the corner separation. In addition to this, this hub corner separation triggers the hubside positive radial movements at the upstream and downstream of hubside of the 3rd stator. This increases the timewise variation of the hubside aerodynamic properties, deviating the shrouded stator off from its designed flow condition further compared with the midspan region. Changing the operating conditions have affected the hubside unsteady flow structures. At near stall cases, the widths of wakes and hub corner separation are increased, but the hubside unsteady flow structure is qualitatively similar to that of the design cases. For the higher flow rate cases, the width and the magnitude of the corner separation are reduced, resulting in the disappearances of a positive radial movement inside the corner separation. | - |
dc.description.abstract | 다단 압축기 슈라우드형 정익 허브의 유동 구조가 상단 동익 후류에 미치는 영향을 파악하기 위해 저속 4단 슈라우드형 축류 압축기의 3단 정익 상단 및 하단에서의 비정상 속도 분포를 핫와이어를 이용하여 최초로 측정하였다.
상단 동익 후류의 폭과 강도는 상단 정익 후류와의 상호작용으로 인해 변동한다. 두 동익 후류 사이에는, 동익 후류로 인해 생긴 순환류로 인해 동익 후류와 유사하게 보이는 유동 구조가 형성된다. 동익 후류로 인해 생긴 유동의 시간에 따른 변화는 유동의 점성과 후류의 늘어남으로 인해 완화된다. 다단 슈라우드형 정익의 허브 모서리 유동 박리는 정익 허브의 비정상 운동학에 영향을 준다. 유동 박리가 허브의 유효 면적을 줄여, 동익 후류의 완화를 억제한다. 또한, 유동 박리로 인해 슈라우드형 정익 상/하단에서 추가적인 반경방향 움직임이 형성된다. 이로 인해 동익 후류로 인한 유동의 시간에 따른 변화의 크기가 증가하여, 유동의 공력 성질이 시간에 따라 변하게 되며, 디자인 공력 조건에서 벗어난다. 압축기의 운전 조건을 바꿀 시 허브의 비정상 유동구조가 변화한다. 낮은 유량에서 운전했을 시, 후류와 모서리 유동 박리의 폭은 늘어나지만, 비정상 유동구조는 설계 운전조건에서의 경우와 정성적으로 동일하다. 높은 유량에서 운전했을 시, 모서리 유동 박리의 폭과 강도가 감소하여, 다른 운전 조건에서 보였던 모서리 박리 안에서의 반경방향 움직임이 사라진다. | - |
dc.description.tableofcontents | Abstract i
Acknowledgments iii List of Figures vii List of Tables xiii Nomenclatures xiv Chapter 1. Introductions 1 1.1 Overview of the Study 1 1.2 Literature Review 9 1.3 Motivations and Objectives of the Study 30 1.4 Thesis Organization 34 Chapter 2. Experimental Configurations 35 2.1 Overview of Turbomachines for Research Purposes 35 2.2 Design Procedure of SNU Compressor 42 2.3 Instrumentations of SNU Compressor 69 2.4 Measuring Technique of 3D Velocity Vector 80 2.5 Measuring Planes and Conditions 82 Chapter 3. Unsteady Kinematics of Multistage Shrouded Stator Flow at Design Point 86 3.1 Unsteady Kinematics of the Flow Upstream of 3rd Stator 86 3.2 Unsteady Kinematics of the Flow Downstream of 3rd Stator 98 3.3 Variation of Aerodynamic Properties Downstream of 3rd Stator 113 Chapter 4. Effect of Corner Separation on Unsteady Kinematics and Flow Properties 118 4.1 Radial Movements Created by 3rd Rotor Wakes and Hubside Corner Separation 119 4.2 Reduced Attenuation of Velocity Disturbances by 3rd Rotor Wake due to Corner Separation 124 4.3 Increased Variation of Hubside Unsteady Aerodynamic Properties 132 Chapter 5. Effect of Flow Coefficients on Unsteady Kinematics of Shrouded Stator Flow 137 5.1 Unsteady Kinematics of Shrouded Stator Flow at Near Stall case 137 5.2 Unsteady Kinematics of Shrouded Stator Flow at Higher Flow Rate case 151 Chapter 6. Discussions 165 6.1 Comparison of the Unsteady Kinematics of Hubside Stator Flow with Different Stator Configuration 165 6.2 Effect of 3rd Rotor Wake on Hubside Vorticity Kinematics of Shrouded Stator 167 6.3 Impact of Hubside Corner Separation on Hubside Unsteady Kinematics of Shrouded Stator Flow and Aerodynamic Properties 169 6.4 Recommendations for Compressor Design 171 Chapter 7. Summary of the Study 172 7.1 Conclusions 172 7.2 Recommendations for the Future Work 175 References 177 Appendix A. Procedure for Selecting Bearings 186 Appendix B. Procedure of Bellmouth Calibration for Measuring Mass Flow Rate 193 Appendix C. Pitch and Yaw Angle Response of Hot-Wires Used for the Experiments 197 Abstract (Korean) 206 | - |
dc.language.iso | eng | - |
dc.publisher | 서울대학교 대학원 | - |
dc.subject | Axial Compressor | - |
dc.subject | Shrouded Stator | - |
dc.subject | Rotor | - |
dc.subject | Unsteady Kinematics | - |
dc.subject | Wake | - |
dc.subject | Hubside | - |
dc.subject | Corner Separation | - |
dc.subject.ddc | 621 | - |
dc.title | Experimental Study on Unsteady Kinematics of Shrouded Multistage Axial Compressor Flow | - |
dc.title.alternative | 다단 슈라우드형 축류 압축기 유동의 비정상 운동학에 대한 실험적 연구 | - |
dc.type | Thesis | - |
dc.type | Dissertation | - |
dc.contributor.AlternativeAuthor | 이재형 | - |
dc.contributor.department | 공과대학 기계항공공학부 | - |
dc.description.degree | Doctor | - |
dc.date.awarded | 2019-08 | - |
dc.contributor.major | 기계전공 | - |
dc.identifier.uci | I804:11032-000000156553 | - |
dc.identifier.holdings | 000000000040▲000000000041▲000000156553▲ | - |
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