S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Mechanical Aerospace Engineering (기계항공공학부) Theses (Ph.D. / Sc.D._기계항공공학부)
Accurate and Efficient Computations on Phase-changing Flows in Thermal Vapor Compressor
열압축기 내 다상유동에 대한 정확하고 효율적인 수치해석 연구구
- 공과대학 기계항공공학부
- Issue Date
- 서울대학교 대학원
- 학위논문 (박사)-- 서울대학교 대학원 : 공과대학 기계항공공학부, 2018. 2. 김종암.
- Most previous numerical researches on flow field inside Thermal Vapor Compressor (TVC) has been conducted neglecting phase changing process around shock-train region. It may provide the plausible results on suction performance of target problem, however, it also can be fallen into erroneous prediction.
The present study focuses above limitations and provides computational improvements through multi-phase flow modeling and analysis. In order to capture the multi-phase flow physics accurately and provide reliable results, several numerical methods and models, including the shock-stable multi-phase AUSMPW+ N scheme, phase changing models, cell-by-cell adaptive mesh refinement technique, the IAPWS-97 equation of states and its SBTL model, are combined into a numerical solver.
The numerical solver incorporating these methods and models is validated with problems that possess similar physics, phase-changing process, shock-train and its interaction with shear mixing layer. Then fundamental flow physics is introduced, and general operation mode of TVC are reproduced to confirm the consistency of present computations. The influence of grid clustering level on to resolution of shear layer and computed suction performance is shown by examining grid dependence. Then simulation results on various TVC systems are compared with single- and multi-phase computations. The comparison explain the reason for yielding more accurate results by multi-phase computations than the other. Based on the computational results and comparisons, necessary of describing the phase-changing process and its influence on two major local physical features are
addressed. The local flow physics are then compared between multi-phase modelings.