Water Spray Evaporative Cooling at System Pressures Below the Triple Point
نویسندگان
چکیده
............................................................................................................................... i ACKNOWLEDGEMENTS ....................................................................................................... ii LIST OF FIGURES .................................................................................................................. vi LIST OF TABLES ................................................................................................................... xii NOMENCLATURE ............................................................................................................... xiii 1.0 INTRODUCTION .................................................................................................... 1 2.0 OUTLINE ................................................................................................................. 9 2.1 LITERATURE SEARCH ..................................................................................................... 10 2.2 RESEARCH TASKS ............................................................................................................ 11 2.3 OBJECTIVES ....................................................................................................................... 14 3.0 EXPERIMENTAL STUDIES ................................................................................. 15 3.1 PROCEDURE FOR DATA ACQUISITION ....................................................................... 32 3.2 DATA REDUCTION PROCESS DETAILS ....................................................................... 37 3.3 SPRAY NOZZLE STARTUP IN VACUUM ...................................................................... 41 3.4 SYSTEM PRESSURE RISE DURING SPRAY PULSE .................................................... 44 3.5 SPRAY ANGLE CHANGE IN VACUUM ......................................................................... 46 3.6 PARASITIC HEAT LOSSES FROM THE DISC ............................................................... 52 iv 4.0 DATA OBSERVATIONS ...................................................................................... 55 4.1 PULSE DURATION ............................................................................................................ 55 4.2 NOZZLE FLOW RATE ....................................................................................................... 57 4.3 DROPLET COOLIING IN FLIGHT ................................................................................... 59 4.4 WATER DEPOSITION AND WATER UTLIZATION EFFICIENCY .............................. 64 4.5 NON-UNIFORM DROPLET SPRAY PATTERN ON THE DISC .................................... 68 4.6 STATIC CONTACT ANGLE MEASUREMENT ............................................................. 70 4.7 OBSERVATIONS OF DROPLETS ON THE DISC ........................................................... 76 4.8 COOLING OF THE DISC TO DETERIMINE THE TIME CONSTANT .......................... 84 4.9 VIDEO DATA ...................................................................................................................... 94 4.10 SPHERICAL CAP GEOMETRY TO DETERMINE DROP VOLUME AND VOLUME/AREA PARAMETER ...................................................................................... 97 4.11 PDPA DATA TO CORROBORATE EXPERIMENTAL MODEL ................................ 101 4.12 MULTIPLE PULSES ....................................................................................................... 104 5.0 MODELING AND COMPARISON WITH EXPERIMENTAL RESULTS ....... 110 5.1 BASIC EXPERIMENTAL MODEL .................................................................................. 114 5.2 SUBLIMATION RATE EVALUATION .......................................................................... 118 5.3 SPACING PARAMETER MODEL ................................................................................... 128 5.4 COOLING PROCESS – HEAT TRANSFER PREDICTIVE MODEL ............................ 136 5.5 UNCERTAINTY ANALYSIS ........................................................................................... 139 5.5.1 THE UNCERTAINTY OF ACCOMODATION COEFFICIENT .............................. 139 5.5.2 UNCERTAINTY IN THE SPACING PARAMETER MODEL .............................. 142 v 5.5.3 UNCERTAINTY IN THE PREDICTIVE HEAT TRANSFER MODEL .................. 142 5.5.4 UNCERTAINTY IN DATA REDUCTION FOR THE TEMPERATURE HISTORY .................................................................................................................................................... 145 6.0 DESIGN AND APPLICATION ........................................................................... 149 6.1 APPLICATION .................................................................................................................. 149 6.2 TEMPERATURE EXCURSION VARIATION ................................................................ 151 6.3 HEAT FLUX RESULTS COMPARISON ......................................................................... 153 7.0 FUTURE WORK .................................................................................................. 155 8.0 CONCLUSION ..................................................................................................... 157 BIBLIOGRAPHY .................................................................................................................. 159 APPENDICES A ............................................................................................................................................. 164 B ............................................................................................................................................. 170 C ............................................................................................................................................. 172 D ............................................................................................................................................. 174 E ............................................................................................................................................. 178 F ............................................................................................................................................. 181 G ............................................................................................................................................. 192 H ............................................................................................................................................. 198
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