EXPERIMENTAL AND COMPUTATIONAL INVESTIGATION OF SNOW

2,35

MB

MELTING ON A HYDRONICALLY HEATED CONCRETE SLAB

181

stron

6383

ID

Oklahoma State University

2003

rok

TABLE OF CONTENTS

CHAPTER 1 1

INTRODUCTION. 1

1.1 OVERVIEW. 1

1.2 STEADY STATE AND TRANSIENT MODELS . 3

1.3 PROBLEM STATEMENT . 4

1.4 OBJECTIVE. 5

CHAPTER 2 6

LITERATURE REVIEW 6

2.1 INTRODUCTION 6

2.2 HYDRONIC SNOW MELTING SYSTEMS OVERVIEW . 6

2.3 STEADY STATE MODELS. 8

2.3.1 1-D Steady State Models 9

2.3.2 2-D steady state models 26

2.4 TRANSIENT MODELS. 29

2.4.1 1-D transient models . 30

2.4.2 2-D transient models . 30

2.5 EXPERIMENTAL INVESTIGATIONS. 61

2.5.1 Snow melting by heating from the bottom (Aoki, et al. 1987) . 62

2.5.2 Hockersmith experimental investigation 66

CHAPTER 3 68

EXPERIMENTAL APPARATUS. 68

3.1 INTRODUCTION 68

3.2 CONCRETE SLAB 69

3.2.1 Base. 72

3.2.2 Heating System. 73

3.2.3 Instrumentation . 75

3.3 SNOW MAKING / ENVIRONMENTAL CHAMBER . 77

3.3.1 Top section 79

3.3.2 Central section 80

3.3.3 Bottom section 82

3.4 MECHANICAL COOLING 83

3.5 SNOW MAKING EQUIPMENT 85

3.6 DATA ACQUISITION CONTROLLER 87

3.7 CONCRETE THERMAL CONDUCTION COEFFICIENT MEASUREMENT APPARATUS . 88

3.8 SPECIFIC HEAT CALCULATION APPARATUS. 90

CHAPTER 4 93

EXPERIMENTATION AND RESULTS . 93

4.1 INTRODUCTION 93

4.2 THERMAL PROPERTY MEASUREMENTS . 94

4.2.1 Density measurement 94

4.2.2 Specific heat of concrete. 96

4.2.3 Thermal conductivity 101

4.2.4 Water diffusion on concrete experiment. 103

4.3 MATHEMATICAL MODEL OF THE CONCRETE SLAB 105

4.3.1 Heat conduction 106

4.3.2 Specific heat and density 109

4.4 INITIAL CONDITIONS AND PHYSICAL PROPERTIES AS REQUIRED INPUT . 111

4.4.1 Experimental procedure 111

4.4.2 Power input calculation. 112

4.4.3 Initial conditions . 118

4.5 EXPERIMENTS 123

4.5.1 Dry surface condition 123

4.5.2 Snow-melting experiments . 125

4.5.3 Revised model with moisture penetration. 140

4.6 SUMMARY 143

CHAPTER 5 145

CONCLUSIONS AND RECOMENDATIONS . 145

5.1 CONCLUSIONS 145

5.2 RECOMMENDATIONS 146

BIBLIOGRAFY 148

APPENDIX A 152

INSTRUMENT CALIBRATION 152

A.1 INTRODUCTION 152

A.2 VARIABLES & CALIBRATION . 152

APPENDIX B 157

DATA LOGGER CONTROLLER. 157

B.1 INTRODUCTION 157

B.2 DESCRIPTION OF THE SYSTEM 157

APPENDIX C 163

GEOMETRIC INFORMATION OF CONCRETE SLAB. 163

C.1 CONCRETE SLAB 163

C.2 MAIN THERMOCOUPLE PLACEMENT DIMENSIONS. 165

C.3 CENTRAL SECTION . 166

APPENDIX D 167

CHARTS AND DATA USED FOR CONCRETE CONDUCTIVITY

CALCULATION. 167

D.1 SAMPLE 1: 167

D.2 DATA OBTAINED FOR SAMPLE NUMBER 2: 169