Numerical Study for the Performance of Thermal Vapor Compressor Under Various Conditions ; 다양한 조건에서의 열압축기 성능에 관한 수치해석 연구

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 기계항공공학부, 2018. 2. 김종암. ; Many previous researches have attempted to associate the complex flow structures with the performances of Thermal Vapor Compressor (TVC) through Effective Area concept. However, the Effective Area concept is ambiguous among the previous researchers and it is only used to analyze the performances qualitatively due to difficulty of calculating the Effective Area. In this present study, two quantitative data, Effective AR and Secondary AR, are firstly introduced to explain the flow structures in TVC and clarify the relationship between flow structures and the performances under various conditions. Through two quantitative data, it indicates that the geometrical characteristics of flow structures in TVC are greatly affected to the performances. As Effective AR increases, the entrainment ratio on design condition (Critical ER) is increased proportionally. It implies that the choked regions of the primary and secondary flow are directly related to the performances. Meanwhile, as Secondary AR increases, the velocity distribution of the secondary flow is decreased. This changes the momentum difference between the primary flow and the secondary flow and the mixing effect in shear layer is also greatly changed. Based on quantitative analysis, five parameters, highly sensitive to the performances of TVC, are derived in the results of the parametric study. In the future, the design optimization of TVC can be carried out based on these results. ; Chapter 1 Introduction 1 1.1 Background 1 1.2 Outline of thesis 5 Chapter 2 Numerical Method 7 2.1 Governing equations for multi-phase flows 7 2.2 Spatial discretization method 9 2.2.1 AUSMPW+_N scheme 9 2.2.2 Compact scheme for viscous flux 11 2.3 Time integration method 12 2.4 Turbulence model 14 2.5 Phase changing model 16 2.6 Equations of state (EOS) 18 Chapter 3 Numerical study for performances of TVC under various condition 24 3.1 Geometry and Boundary condition 24 3.2 Flow analysis of TVC 25 3.2.1 Flow characteristics in ...