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Computational Methods for Homogeneous Multi-phase Real Fluid Flows at All Speeds : 전 마하수 균질 혼합류 실제유체 다상유동을 위한 수치기법 개발 및 응용
DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | 김종암 | - |
dc.contributor.author | Hyeongjun Kim | - |
dc.date.accessioned | 2017-07-13T06:30:41Z | - |
dc.date.available | 2017-07-13T06:30:41Z | - |
dc.date.issued | 2017-02 | - |
dc.identifier.other | 000000142459 | - |
dc.identifier.uri | https://hdl.handle.net/10371/118611 | - |
dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2017. 2. 김종암. | - |
dc.description.abstract | Computations of all-speed multi-phase real fluid flows are known to be very
demanding owing to several issues that include robust capturing of two-phase shock/phase discontinuity and proper scaling of numerical flux at steady/unsteady all-speed flows. This paper contributes several solutions for addressing difficulties arising from these issues. It consists of two part: development of accurate and efficient numerical schemes for multi-phase real fluid flows at all-speeds and high fidelity computation of a cryogenic cavitating flows around turbopump inducer. In first part, the baseline numerical schemes, RoeM and AUSMPW+ schemes for multi-phase flows, are extended for real fluid flow and improved for unsteady low Mach number flows. The shock-discontinuity-sensing term used in the two-phase RoeM and AUSMPW+ schemes is modified, as the existing shock-discontinuity-sensing term is not suitable for complex equation of state of real fluids. The accuracy of the two-phase RoeM and AUSMPW+ schemes for unsteady low Mach number flows is then improved through separate scaling of the velocity- and pressure-difference terms. it is shown that the proposed schemes, called RoeM N and AUSMPW+ N schemes, are capable of robustly and accurately capturing phenomena involving phase and shock discontinuities and interactions between them for numerous two-phase problems. Signifi- cant improvements in accuracy are observed for the unsteady convection- and acoustic-dominated problems over the previous two-phase RoeM and AUSMPW+ schemes. Finally, steam condensing and cryogenic cavitation problems are presented to demonstrate the accurate and robust behavior of the proposed schemes in simulating two-phase real fluid flows at all speeds. Based on the newly developed numerical methods, the second part deal with the numerical computations of cryogenic cavitating flows around turbopump inducer in liquid rocket. Quantifying thermal effect of cavitation is very important to understand and predict inducer performance. To better understand their impact on inducer performance, extensive numerical simulations of three-dimensional KARI turbopump inducer are carried out under various flow conditions with water and cryogenic fluids, and the difference in inducer flow physics depending on the working fluid are examined. | - |
dc.description.tableofcontents | Chapter 1 Introduction 1
1.1 Computations of homogeneous multi-phase real fluid flows at all speeds 1 1.2 Cryogenic cavitating flows around turbopump inducer 3 1.3 Outline of thesis 5 Chapter 2 Numerical Modeling 7 2.1 Governing equations 7 2.1.1 Governing equations in rotating frame of reference 10 2.2 Equation of state (EOS) 13 2.2.1 Ideal gas EOS 14 2.2.2 Stiffened gas EOS 15 2.2.3 IAPWS97 formulation 15 2.2.4 Spline-based table look-up method 21 2.3 Cavitation model 26 2.3.1 Merkle cavitation model 27 2.3.2 Kunz cavitation model 27 2.3.3 Schnerr-Sauer cavitation model 28 2.3.4 Singhal cavitation model 29 2.4 Turbulence Model 30 2.4.1 SST two-equation model of Menter 31 2.4.2 SST model with rotation/curvature correction 34 2.5 System preconditioning 36 Chapter 3 Numerical Methods 40 3.1 Baseline inviscid flux schemes 41 3.1.1 Two-phase AUSMPW+ scheme 41 3.1.2 Two-phase RoeM scheme 44 3.2 Compact scheme for viscous flux 46 3.3 Multi-dimensional limiting process (MLP) 47 3.4 Time integration 49 3.4.1 Explicit time integration scheme 50 3.4.2 Implicit time integration scheme 50 Chapter 4 Improvement of Baseline Inviscid Flux Schemes 59 4.1 Shock-discontinuity-sensing term for real fluid flows 59 4.2 Scaling of numerical fluxes 64 4.2.1 AUSMPW+ N scheme 65 4.2.2 RoeM N scheme 68 Chapter 5 Numerical Results 72 5.1 Two-phase shock-tube 74 5.2 Shock/water-column interaction 75 5.3 Steady inviscid flow around a cylinder 78 5.4 Unsteady inviscid vortex propagation 84 5.5 Oscillating back pressure in a pipe 86 5.6 Steam condensing flow in a nozzle 90 5.7 Cryogenic cavitating flow around a hydrofoil 94 5.8 Cavitating flows around turbopump inducer 95 5.8.1 Cavitating flows in cold water 99 5.8.2 Cavitating flows in cryogenic fluids 101 Chapter 6 Conclusions 112 6.1 Summary 112 6.2 Future works 114 초록 124 | - |
dc.format | application/pdf | - |
dc.format.extent | 17836047 bytes | - |
dc.format.medium | application/pdf | - |
dc.language.iso | en | - |
dc.publisher | 서울대학교 대학원 | - |
dc.subject | RoeM 수치기법 | - |
dc.subject | AUSMPW+ 수치기법 | - |
dc.subject | 다상유동 | - |
dc.subject | 전 마하수 유동 | - |
dc.subject | 실제 유체 유동 | - |
dc.subject | 비정상 예조건화 기법 | - |
dc.subject | 극저온 공동현상 | - |
dc.subject | 온도효과 | - |
dc.subject | 터보펌프 인듀서 | - |
dc.subject.ddc | 621 | - |
dc.title | Computational Methods for Homogeneous Multi-phase Real Fluid Flows at All Speeds | - |
dc.title.alternative | 전 마하수 균질 혼합류 실제유체 다상유동을 위한 수치기법 개발 및 응용 | - |
dc.type | Thesis | - |
dc.contributor.AlternativeAuthor | 김형준 | - |
dc.description.degree | Doctor | - |
dc.citation.pages | 130 | - |
dc.contributor.affiliation | 공과대학 기계항공공학부 | - |
dc.date.awarded | 2017-02 | - |
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