목차

CHAPTER 1: Introduction 1
1.1 Background 1
1.2 Research objectives 6
1.3 Organization of thesis 7
CHAPTER 2: Literature review 9
2.1 Performance of R448A in refrigeration systems 9
2.2 Flow boiling heat transfer coefficient and pressure drop literature 11
2.2.1 R448A literature 11
2.2.2 Zeotropic mixture literature 12
2.2.3 Multiport mini-channel literature 16
CHAPTER 3: Experimental apparatus and method 20
3.1 Experimental systems and procedure 20
3.1.1 Experimental facility 20
3.1.2 Experimental procedure 24
3.2 Data reduction and uncertainty analysis 26
3.2.1 Data reduction 26
3.2.2 Uncertainty analysis 27
CHAPTER 4: Result and discussion 29
4.1 Flow pattern of R448A inside multiport mini-channel tube 29
4.2 Heat transfer coefficients and pressure drops in five test sections 31
4.2.1 Heat transfer coefficient and pressure drop in tube A (dh = 1.16 mm) 31
4.2.2 Heat transfer coefficient and pressure drop in tube B (dh = 1.14 mm) 38
4.2.3 Heat transfer coefficient and pressure drop in tube D (dh = 1.07 mm) 46
4.2.4 Heat transfer coefficient and pressure drop in tube E (dh = 0.969 mm) 54
4.2.5 Heat transfer coefficient and pressure drop in tube C (dh = 0.831 mm) 62
4.3 General discussion of the heat transfer coefficient 69
4.3.1 Effect of mass flux on heat transfer coefficient 69
4.3.2 Effect of heat flux on heat transfer coefficient 70
4.3.3 Effect of saturation temperature on heat transfer coefficient 71
4.3.4 Comparison between heat transfer coefficients of R448A and R410A 72
4.4 General discussion of pressure drop 73
4.4.1 Effect of mass flux on pressure drop 73
4.4.2 Effect of heat flux on pressure drop 74
4.4.3 Effect of saturation temperature on pressure drop 74
CHAPTER 5: Correlation evaluation and development 75
5.1 Heat transfer coefficient correlation 75
5.1.1 Evaluation 75
5.1.2 Correlation development 89
5.2 Pressure drop correlation 93
5.2.1 Evaluation 93
5.2.2 Correlation development 99
CHAPTER 6: Conclusion 101