질소 저온유지장치의 self-pressurization 경향에 관한 수치해석적 비교)
- Alternative Title
- Numerical Study on Comparison of Self-Pressurization Behavior of Liquid Nitrogen Cryostat
- Abstract
- Recently, the numbers of cryogenic storage system are growing rapidly, in the land, sea and space. These applications included the cryopreservation of umbilical cord blood. The reason for preservation of umbilical cord blood is umbilical cord blood contains both hematopoietic stem cell and pluripotent mesenchymal cells has been using in treatment many type of leukimias, hemoglobinopathies, cancer, genetic disease and inborn errors of metabolism. Umbilical cord blood that stored under cryopreservation does not have deterioration in the quality of the cells after ten years and have performed as well as new ones. Thus, the good performance cryostat to store umbilical cord blood is needed. Since cryogens are stored at very low temperatures, the cryogenic storage systems are quite sensitive to heat leaks. Even though the vessel operated under sealed condition with vacuum insulation and reflective coating are used, the heat leakage into the vessel still unavoidable causing pressure rise.
This paper concerns with numerical study of self-pressurization to analyses the optimum design cryostat with the variation volume fraction, effect of heat flux and storage pressure of liquid nitrogen. The results show that as the volume fraction increases, the pressure rise reduces. The relatively low atmosphere pressure is better than the higher one. Higher heat flux leads the pressure rise rate increases faster than low one. The heat pipe system has significant affect on reducing the pressure rise rate. In addition, the effect of low temperature on structure of several material analyzed.
- Issued Date
- 2010
- Awarded Date
- 2010. 2
- Type
- Dissertation
- Publisher
- 부경대학교
- Alternative Author(s)
- muhammad irham mahfud
- Affiliation
- 부경대학교 냉동공조공학과
- Department
- 대학원 냉동공조학과
- Advisor
- 김은필
- Table Of Contents
- Contents
Abstract iv
I Introduction 1
1.1. Umbilical Cord Blood 1
1.2. Problem Definition and Objective 2
1.3. The Structure of the thesis 4
1.4. Science Contribution of the Thesis 5
II Background Knowledge 6
2.1. Cryostat 6
2.2. Heat Transfer 7
2.3. Liquid Nitrogen 9
2.4. Computational Fluid Dynamic 12
2.5. Ansys Fluent Code 14
III Overview Physical and Numerical Models 16
3.1. Introduction 16
3.2. The Pressure Based Segregate and Couple Algorithm 16
3.3. Multiphase Models 19
3.3.1. The VOF model 19
3.3.2. The mixture model 19
3.3.3. The eulerian model 20
3.4. Multiphase Mixture Models 20
3.5. Simulation Steps 22
3.6. Boundary and Initial Condition 25
3.7. Heat Pipe System 26
IV Result and Analysis 27
4.1 Self-Pressurization 27
4.1.1. Different mesh generation 31
4.1.2. Effect of volume Fraction 32
4.1.3. Effect of storage pressure 34
4.1.4. Effect of heat flux 34
4.1.5. Effect of cooler 37
4.2 Thermal Stratification 38
V Thermal Structure Analysis 40
5.1. Thermal Expansion 40
5.2. Cryogenic Vessel and Design in Ansys 45
5.3. Thermal Structure Analysis 50
5.4. Comparison with Common Cryogenic Material 55
VI Conclusions 56
Acknowledgements 58
References
- Degree
- Master
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