NUMERICAL AND EXPERIMENTAL ANALYSIS OF TURBULENT CONVECTIVE HEAT TRANSFER WITHIN A TYPICAL PRESSURIZED WATER REACTOR WITH NANOFLUIDS  

 

 

TABLE OF CONTENTS

SUBJECT                                                                                                  Page No.

LIST OF FIGURES…………………………………….……….……….VIII

LIST OF TABLES………………………..…………………………………XI

NOMENCLATURE……………………………….………………………XIII

CHAPTER 1 INTRODUCTION ……………………………………………2

• Introduction……………………………………………………………..2

1.2 Problem statement and research methodology…………………………..5

1.3 Thesis objectives……………………………………….………………..8

CHAPTER 2 TECHNICAL BACKGROUND …………………………….10

2.1 Introduction……………………………………………………………10

2.2 Heat transfer enhancement of nanofluids………………………………11

2.3 Surface modification of nanoparticles…………………………………16

2.4 Nanofluid-engineered nuclear coolants and safety features…………..19

2.4.1 Emergency core cooling system……………………….……………19

2.4.2 In-vessel retention capability…………………………………21

2.5 Neutronic analysis of nanofluids as working fluids……………………24

2.6 Chemistry and irradiation effects on nanofluids ………………………27

2.7 A review on previous sub-channel analysis……………………………30

CHAPTER 3 EXPERIMENTAL ANALYSIS………………….….………38

3.1 Introduction……………………………………………………………38

3.1.1 Pressurized water reactor cooling system……………………39

3.1.2 Light water small modular reactors………………….………40

3.1.3 System-integrated modular advanced reactor………………..42

3.2 Experimentation methodology…………………………………………44

3.2.1 Test section design details……………………………………45

3.2.1.1 Flow housing………………………………………..53

3.2.1.2 Inlet and outlet design………………………………54

3.2.1.3 Heated rod bundle design details……………………56

3.2.1.4 The grid spacer design and fabrication……………..60

3.2.2 Hydraulic loop……………………………………………….61

3.2.2.1 Pumping requirements…………………………………………62

3.2.2.2 Heat exchanger……………………………………..63

3.2.2.3 Insulation……………………………………………64

3.3 Instrumentation and control……………………………………………65

3.3.1 Flow measurement and control……………………….………65

3.3.2 Pressure measurements………………………………………67

3.3.3 Power control system…………………………………………68

3.3.4 Pressurizer and safety system………………………………..71

3.3.5. Real time data acquisition and monitoring system………….73

3.4 Calibration of experimental loop……………………………..……….75

3.4.1 Thermocouple calibration……………………………………76

3.5 Initial tests and loop calibration………………………………………..79

3.5.1 Measurement techniques……………………………………..80

3.5.1.1 Heat flux measurement……………………………..81

3.5.1.2 Temperature measurements…………………………81

3.5.1.3 Pressure measurements consideration………………84

3.6 Preparation and estimation of nanofluid properties…………………….91

3.6.1Experimentation methodology………………….……..92

3.6.2.1 Nanoparticle preparation…………………….88

3.6.2.2 Synthesis of nanofluids………………………89

3.6.2 Thermophysical properties characterization………….90

CHAPTER 4 NUMERICAL ANALYSIS……………………….………..100

4.1 introduction…………………………………………………………..100

4.2 methodology…………………………………………………….……101

4.2.1 Mathematical modeling……………………………………..101

4.2.2 Computational domain and meshes…………………………102

4.2.3 Mesh generation sensitivity and turbulence model…………105

4.2.4 Boundary conditions……………………………….……….106

4.2.5 Numerical method…………………………………….…….107

4.2.6 Thermophysical properties of the nanofluids………………108

4.3 Numerical model validation and benchmarking results……………….110

4.3.1 Velocity and turbulence…………………………….………111

4.3.2 Temperature distribution…………………………………….119

4.3.3 Heat transfer………………………………………………….120

4.3.4 Pressure drop………………………………………….…….127

4.4 Summary of CFD model validation …………………………………132

CHAPTER 5 RESULTS AND DISCUSSION……………………………135

5.1 Introduction…………………………………………………..…..…..135

5.2 Single phase convective heat transfer …………..……………………136

5.2.1 Water test results ……………..…………………………….137

5.2.2 Nanofluid convective experiments …………………..…….147

5.3 Single phase pressure drop analysis………….………………………151

5.3.1 Water tests……………………………………………..……152

CHAPTER 6 CONCLUSIONS……………………………………………162

REFERENCES……………….…………………………………………..166

APPENDIX A. INSTRUMENTATION ERROR ANALYSIS ……..…..182

LIST OF FIGURES

 

 

Fig. 1-1 Types of nuclear reactors (Knief, 2008)……………………………4

Fig. 1-2 The Research flowchart……………………………………………7

Fig. 2-1 Nanostructures for boiling and CHF enhancement (Chen et al., 2009)………………………………………………………………………..18

Fig. 2-2 Nanofluid-engineered SIT (Kang et al., 2011)……………………..21

Fig. 2-3 Nanofluid tanks inject directly into the reactor cavity (Buongiorno et al., 2009)………………………………………………………….……..22

Fig. 2-4 Diffusion of nanofluids to ex-vessel cooling channel (Buongiorno et al., 2009)…………………………………………………..…………….23

Fig. 2-5 Effective multiplication factors of core for different types of nanoparticles with different volume fractions (Hadad et al., 2010)………..25

Fig. 2-6 Local Power Peaking Factor (LPPF) maps for pure water and Al₂O₃/water nanofluids (Hadad et al., 2010)………………………………26

Fig. 2-7 The effect of Al₂O₃ nanoparticle deposition layer on K_eff and with different nanofluid volume fractions (Hadad et al., 2010)…………………26

Fig. 2-8 Concentrations as a function of dose in Lucas irradiation tests (Lucas, 2006)………………………………………………………….…..28

Fig. 2-9 Irradiation sample mean particle size in Lucas irradiation tests (Lucas, 2006)………………………………………………………………29

Fig. 2-10 Irradiation sample pH in Lucas irradiation tests (Lucas, 2006)………………………………………………………………………29

Fig. 3-1 The PWR primary cooling system…………………………………39

 Fig. 3-2 The SMART reactor vessel assembly (Choi et al., 2013)…………41

Fig. 3-3 The SMART core configuration (Kim et al., 2011)………………43

Fig. 3-4 The experimentation methodology flowchart……………………44

Fig. 3-5 A) Simplified schematic diagram of a typical PWR B) Simplified experimental test section to model the PWR core…………………………47

Fig. 3-6 The simplified schematic diagram of the hydraulic loop…………47

Fig. 3-7 Rod bundles in square arrays. (a) Square channel (b) Quasi-infinite charnel……………………………………………………………………..48

Fig. 3-8 The NABI test facility schematic…………………………………50

Fig. 3-9 The NABI test facility……………………………………………51

Fig. 3-10 The detailed drawing of the test section…………………………52

Fig. 3-11 The drawing of a typical PWR lower plenum…………………..54

Fig. 3-12 The inlet flow distributor………………………………………….55

Fig. 3-13 The outlet and the collecting tank………………………………55

Fig. 3-14 Schematic cross-sectional view of the NABI test section………56

Fig. 3-15 Numeration of the subchannels…………………………………56

Fig. 3-16 Cross-sectional view of the heated rod…………………………..57

Fig. 3-17 Thermocouple arrangements along the test section…………….59

Fig. 3-18 The location of the thermocouples at outlet……………………..59

Fig. 3-19 The grid spacers…………………………………………………60

Fig. 3-20 The reservoir tank…………………………………………………61

Fig. 3-21 Pumping curve provided by Wilo Company (Karassik et al., 2007)……………………………………………………………………….62

Fig. 3-22 The centrifugal pump……………………………………………63

Fig. 3-23 Brazed Plate Heat Exchanger (BPHE)……………………………63

Fig. 3-24 TOSHIBA-LF400 magnetic flowmeter…………………………66

Fig. 3-25 differential pressure gauge………………………………………68

Fig. 3-26 The power control system………………………………………69

Fig. 3-27 Schematic diagram of power controller…………………………71

Fig. 3-28 Signal B profile to control the power level……………………..71

Fig. 3-29 The pressurizer system……………………………………………..72

Fig. 3-30 The nitrogen injection system…………………………………..72

Fig. 3-31 The data acquisition system flowchart………………………….74

Fig. 3-32 the Dry-Well 9140 front panel……………………………………..77

Fig. 3-33 The digital thermometer…………………………………………77

Fig. 3-34 Schematic representation of the experimental procedure………..79

 Fig. 3-35 Location of miniature thermocouples for bulk and surface temperature measurements…………………………………………………82

Fig. 3-36 The location of the thermocouple along the test section………..82

Fig. 3-37 Water test pressure loss results……………………………………..84

Fig. 3-38 Photographic view of Aluminum oxide and Zirconium (IV) oxide commercial nanoparticle from Sigma Aldrich Company…………………89

Fig. 3-39 KD2 Pro thermal properties analyzer……………………………91

Fig. 3-40 KS-1 sensor needle used for experiments………………………91

Fig 3-41 The KD2 Pro with nanofluid sample in the water bath for measurement at different temperature……………………..………………94

Fig. 3-42 Density of the Alumina nanofluid……………………..…………95

Fig. 3-43 Density of the Zirconia nanofluid…………………..…………..96

Fig. 3-44 Specific heat of the Alumina nanofluid…………………………..96

Fig. 3-45 Specific heat of the Zirconia nanofluid…………………..……..97

Fig. 3-46 Thermal conductivity of 0.1 % alumina nanofluid………………97

Fig. 3-47 Thermal conductivity of 0.25 % alumina nanofluid……….……98

Fig. 3-48 Thermal conductivity of 0.5 % alumina nanofluid……………..98

Fig. 3-49 Thermal conductivity of 1.0 % Alumina nanofluid……….……98

Fig. 4-1 Computational domain with no grid spacer…………………….103

Fig. 4-2 Meshes with no grid spacer……………………………………..103

Fig. 4-3 Computational domain with grid spacer………………………..104

Fig. 4-4 Cross-sectional view of one subchannel with grid spacer………105

Fig. 4-5 Normalized axial velocity profiles………………………………113

Fig. 4-6 Vorticity contour above the grid spacer (Re = 65000)……………114

Fig. 4-7 Streamlines and flow pattern downstream grid spacer…………..115

Fig. 4-8 Axial variation of TKE and helicity ……………………………116

Fig. 4-9 Normalized velocity distributions along the centerline channel..117

Fig. 4-10 Normalized velocity distribution ………………………………117

Fig. 4-11 Contour of velocity and turbulent kinetic energy………………118

Fig. 4-12 Turbulent intensity at the channel at Re = 80×10³……………..119

Fig. 4-13 Temperature profile at the outlet……………………………….120

Fig. 4-14 Coolant temperature distributions along centerline of channel..120

Fig. 4-15 Average heat transfer coefficient for concentrations and Re….124

Fig. 4-16 Comparison of average Nu with the correlations………………126

Fig. 4-17 Differences of FLUENT result from correlations……………..127

Fig. 4-18 Pressure loss along the channel………………………………….128

Fig. 4-19 Calculated pressure drop using available correlation………….128

Fig. 4-20 Pressure distribution in subchannel ……………………………130

Fig. 4-21 Pressure drop along channel……………………………………131

Fig. 4-22 Performance of the Blasius correlation for pressure drop……..131

Fig. 5-1 Nu vs Re for the first span of rod bundle………………………..137

Fig. 5-2 Nu vs Re for the second span of rod bundle………………..……138

Fig. 5-3 Nu vs Re for the third span of rod bundle………………………..138

Fig. 5-4 Nu vs Re for the last span of rod bundle……………………………139

Fig. 5-5 CAA Nu vs Re for the central rod………………………..……..140

Fig. 5-6 Comparison of new curve and experimental data………………144

Fig. 5-7 The Nusselt numbers of nanofluids with the Reynolds numbers compared with the water…………………………………………………..148

Fig. 5-8 Pressure drop along the test section ……………………………152

Fig. 5-9 Pressure drops of the lowermost grid spacer at different Re……..154

Fig 5-10 High Thermal Performance spacer grid design…………………154

Fig. 5-11 Simplified HTP grid spacer in the test section…………………154

Fig. 5-12 Pressure drop along the rest section as a function of Re numbers…………………………………………………………………..158

Fig. 5-13 Variation of average Nusselt divided by pressure drop (kPa) along the rest section as a function of Re numbers……………………………..159

 

 

 

 

 

 

 

 

LIST OF TABLES

 

 

Table 1-1 Basic features of major power reactor types………………….…3

Table 2-1 Specific heat capacity and thermal conductivity for different materials (Sarkar, 2011)………………………………………………..….12

Table 2-2 Comparison of design parameters and independence of safety systems and nanofluid injection system (Bang et al., 2009)…………………21

Table 2-3 Recent CFD analysis of in-core coolant mixing PWRs………..36

Table 3-1 Medium and small sized reactors (Chio et al, 2013)………..….41

Table 3-2 The SMART characteristics (Kim et al., 2011)…………………43

Table 3-3 The specifications of heater rod bundle……………………..….52

Table 3-4 The heated rod bundle specifications (Rosal et al., 2010)…..….58

Table 3-5 The numbering of K-Type thermocouple used in the test section………………………………………………………………58

Table 3-6 General specification of TOSHIBA LF400 (Karassik et al., 2007)……………………………………………………………………….67

Table 3-7 Accuracy of TOSHIBA-LF400 (Karassik et al., 2007)……………………………………………………………………….67

Table 3-8 The pressure gauge specification (Karassik et al, 2007)……………………………………………………………………….68

Table 3-9 Data acquisition channel list for data acquisition system………………………………………………………………………75

Table 3-10 Specifications of drywell calibrator (Rubin et al., 2010)……. 78

Table 3-11 Digital thermometers Specifications (Rubin, 2010)…………. 78

Table 3-12 Initial condition for initial tests…………………………..……80

Table 3-13 The selective summary of the thermal conductivity enhancement in Al₂O₃-based nanofluids (Sridhara & Satapathy, 2011)…………………87

Table 3-14 Sigma-Aldrich Aluminum oxide nanopowder (Xuan & Li, 2003)……………………………………………………………………….88

Table 3-15 Sigma-Aldrich Zirconium (IV) oxide nanopowder (Xuan & Li, 2003)…………………………………..…………………………………..89

Table 3-16 KD2 Pro specification (Xuan & Li, 2003)…………………….92

Table 3-17 The specifications of KD2 Pro sensors for measurements (Xuan & Li, 2003)…………………………………………….…………………..92

Table 3-18 The investigated properties and measurement techniques……95

Table 4-1 Mesh specifications and mesh refinement ratio……………….105

Table 4-2 MRR and ΔNu among the different tested meshes……………106

Table 4-3 Inlet velocities and Re…………………………………………107

Table 4-4 Al₂O₃ nanoparticle at temperature of 293 K………………..…110

Table 4-5 Properties of water based Al₂O₃/water nanofluid at different volume fractions equaling 1% and 4% at T₀=293K……………………..110

Table 4-6 Span-averaged heat transfer enhancement (Re=35,000) for different turbulence model……………………………………………….122

Table 4-7 The average Nu………………………………………………..125

Table 5-1 The constant coefficient of correlations………………………143

Table 5-2 Span-averaged heat transfer enhancement (Re=40,000)………146