meat transfer from in-line and perpendicular arrangements ofcylinders

273 Pages·2012·8.58 MB·English

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\MEAT TRANSFER FROM IN-LINE AND PERPENDICULAR ARRANGEMENTS OF CYLINDERS
IN STEADY AND PULSATING CROSSFLOW
by
Terrance Michael yandenßerghel
Thesis submitted to the Faculty of the
Virginia Polytechnic Institute and State University
in partial fulfillment of the requirements for the degree of
Master of Science
in
Mechanical Engineering
APPROVED:
(E (
D. P. Telionis W. C. Thomas
September, 1985
Blacksburg, Virginia
HEAT TRANSFER FROM IN-LINE AND PERPENDICULAR ARRANGEMENTS OF CYLINDERS
, IN STEADY AND PULSATING CROSSFLOW
Terrance Michael Vandenßerghe
ß
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T. E. Diller, Chairman
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Mechanical Engineering
(ABSTRACT)
An investigation was conducted to determine the effect of organized
flow pulsations on mean heat transfer from a single cylinder, in-line
arrangements and perpendicular arrangements of cylinders. Pulsation
frequencies of up to twice the natural vortex shedding frequency and zero
to peak. amplitudes as high as 36 percent were used. Pulsations were _
sinusoidal with at least 93 percent of the power at the fundamental fre-
' quency. Turbulence levels (Tu=0.5 percent) were not altered by the ad-
dition of unsteady flow. Reynolds number ranged from 23,000<Re<49,000.
Results for heat transfer on the front and back of the cylinder are given
for a constant wall temperature boundary condition. Heat transfer meas-
urements were made by applying a heat balance to a thick walled copper
tube divided into four individually heated segments with guard. heaters
located at each end.
Mean heat transfer was found to increase for all three arrangements
when organized flow pulsations were applied. For a single cylinder and
for perpendicular arrangements, heat transfer increases were found pri-
marily on the back of the cylinder. For in-line arrangements, increases
occurred mostly on the front of the cylinder. for the range of pitch
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ratio most useful to heat exchanger design, in-line arrangements were
found to have a higher Nusselt number than perpendicular arrangements.
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ACKNOWLEDGEMENTS
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First and foremost, I would like to extend my sincere appreciation ,
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to Dr. T. E. Diller for his guidance, insight and patience during his
supervision of this thesis. I thank him for his constant support and
the genuine concern that he showed for this work.
Additionally, I would like to thank the other members of my advisory
committee, Dr. D. P. Telionis and Dr. W. C. Thomas for giving their time
to provide input to this thesis project.
The support of this project as part of contract No. DE-A505-82ER
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12022, under the direction of Dr. Oscar Manley from the Office of Basic
Energy Research, Department of Energy, is gratefully acknowledged.
I would also like to thank my parents for supporting my educational
endeavors throughout my college years. They have provided an atmosphere
particularly conducive to learning and they have always encouraged me to
fulfill my ambitions.
Finally, special thanks to Dr. Robert Mahan for the advice he has
given me both here at Virginia Tech and while I was a student in France.
His interest in his students and his willingness to help them certainly
exceeds what is normally considered the responsibility of a professor.
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Acknowledgements iv 2
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TABLE OF CONTENTS1
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1.0 INTRODUCTION ........................ 1 1
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2.0 LITERATURE REVIEW ...................... 3
3.0 EXPERIMENTAL APPARATUS AND PROCEDURE ............ 25
3.1 Test Cylinder ........................ 25
3.2 Wind Tunnel ......................... 36
3.3 Arrangement of Cylinders ................... 42
3.4 Experimental Procedure .................... 43
3.4.1 Temperature Measurement .................. 47
3.4.2 Voltage Measurement .................... 49
3.4.3 Velocity Measurement ................... 50
3.4.4 Measurement of Turbulence Level, Pulsation Frequency and Am-
plitude ............................. 51
3.5 Data Reduction ........................ 52
4.0 RESULTS ........................... 57
4.1 Single Cylinder ....................... 58
4.2 In-Line Arrangements of
Cylinders. ........ 67
4.3 Perpendicular Arrangements .................. 92
3.0 DISCUSSION OF RESULTS ................... 109
Table of Contents v
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5.1 Single cylinder ...................... 109 I
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5.2 In-Line Arrangements. ................... 112 I
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5.3 Perpendicular Arrangements ................. 113
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6.0 CONCLUSIONS AND RECOMMENDATIONS .............. 115
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6.1 Single cylinder ...................... 115
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6.2 In—Line Arrangements: ................... 116
6.3 Perpendicular Arrangements ................. 117
6.4 Recommendations ...................... 117
LIST OF REFERENCES ....................... 119
APPENDIX A. EXTERNAL ERROR ANALYSIS .............- 123
APPENDIX B. TEMPERATURE CONTROL AND HEATER VOLTAGE MEASUREMENT USING
EUROTHERM CONTROLLERS ..................... 128
B.1 Principal of Operation of PID Temperature Controllers . . . 128
B.2 Controller Output Power Measurement ............ 131
B.3 Controller Settings .................... 134
B.4 HP-4lCV Voltage Acquition Program ............. 136
APPENDIX C. ANALYSIS OF INSULATION LOSSES ........... 144
APPENDIX D. ANALYSIS OF CONDUCTION LOSSES BETWEEN SEGMENTS . .
157
APPENDIX E. THERMAL CONDUCTIVITY OF INSULATING MATERIALS . . .
163
Table of Contents vi
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APPENDIX F. PULSATION WAVEFORMS ................ 171
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APPENDIX G. PROGRAM LISTINGS ................. 180 1
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APPENDIX H. EXPERIMENTAL DATA ................. 203
VITA .............................. 257
Table of Ccmterxtzs vii
LIST OF ILLUSTRATIONS
Figure 1. Flow around a single cylinder from Reference 5 .... 5
Figure 2. Local heat transfer measurements by different authors from
Reference 35 ..................... 7
”
Figure 3. Combined effect of blockage and freestream turbulence from
Reference 2 ...................... 10
Figure 4. Flow around two in-line cylinders from Reference 26 . . 17
Figure 5. Correlations for predicting jump phenomenon from Reference
33 .......................... 20
Figure 6. Local heat transfer for three cylinders from Reference 32 23
Figure 7. Overall heat transfer for an in-line arrangement from
Reference 31 ..................... 24
Figure 8. The cylinder model used for this investigation .... 26
Figure 9. Method for fastening copper segments to support tube . 28
Figure 10. Insulation strips separating cylinder segments .... 29
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Figure 11. Thermocouple locations on the cylinder model ..... 32
Figure 12. A typical temperature distribution on the cylinder for
Re=49,000 ....................... 34
Figure 13. Construction of thermocouple plugs. .......... 35
Figure 14. The pulsating flow wind tunnel used for this investigstion
from Referenceerence 35 ................ 37
Figure 15. Position of rotating vanes for sinusoidal waveforms . . 39
Figure 16. Waveform and frequency content for fd= 2 Hz ...... 40
Figure 17. Modifications to the wind tunnel to increase pulsation
amplitude. ...................... 41
Figure 18. Definition of pitch ratio for in-line arrangements and
perpendicular arrangements of cylinders. ....... 44
Figure 19. Mounting acrylic cylinders in the test section for in-line
arrangements ..................... 45
Figure 20. Perpendicular arrangements of cylinders ........ 46
List of Illustrations viii
Figure 21. Schematic of experimental system ........... 48
Figure 22. Nusselt number Variation with Reynolds number for the front
and back ....................... 61
Figure 23. Overall Nusselt number Variation with Reynolds number . 62
Figure 24. Relative Nusselt number dependence on pulsation frequency,
front and back .................... 64
Figure 25. Relative Nusselt number dependence on pulsation frequency,
overall ........................ 65
Figure 26. Nusselt number increase per unit amplitude, front and back 68
Figure 27. Nusselt number increase per unit amplitude, overall . . 69
Figure 28. Effect of pulsation amplitude on relative Nusselt number,
front and back .................... 70
Figure 29. Effect of pulsation amplitude on relative Nusselt number,
overall ........................ 71
Figure 30. Driving and Shedding frequencies in the wake of a single
cylinder at Re=32,000. ................ 72
· Figure 31. Nusselt number at various spacings for Re=49,000, front
and back. ....................... 74
Figure 32. Nusselt number at various spacings for Re=49,000, overall 75
Figure 33. Nusselt number dependence on Reynolds number for L/D=1.1,
front and back. .................... 77
Figure 34. Nusselt number dependence on Reynolds number for L/D=1.1,
overall. ....................... 78
Figure 35. Relative Nusselt number dependence on driving frequency
for L/D=l.l, front and back. ............. 79
Figure 36. Relative Nusselt number dependence on driving frequency
for L/D=1.1, overall. ................. 80
Figure 37. Relative Nusselt number dependence on driving frequency
for L/D=l.25, front and back. ............. 81
Figure 38. Relative Nusselt number dependence on driving frequency
for L/D=l.25, overall. ................ 82
List of Illustrations ix
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Figure 39. Relative Nusselt number dependence on driving frequency
for L/D=1.8, front and back. ............. 83
Figure 40. Relative Nusselt number dependence on driving frequency
for L/D=l.8, overall. ................. 84
Figure 41. Relative Nusselt number dependence on driving frequency
for L/D=4.75, front and back. ............. 85
Figure 42. Relative Nusselt number dependence on driving frequency
for L/D=4.75, overall. ................ 86
Figure 43. Shedding frequencies in the wake near the jump phenomenon
for L/d =1.1. ..................... 88
Figure 44. Shedding frequencies between the first and second cylin-
ders near the jump phenomenon for L/d =l.l. ...... 89
Figure 45. Shedding frequencies in the wake at different driving
frequencies for Re=48,000, L/D=l.1. .......... 90
Figure 46. Shedding frequencies observed for fd/fS=.2, L/D=1.25. . 91
Figure 47. Steady flow Nusselt number for in-line and perpendicular
arrangements at Re=49,000, front and back. ...... 94
Figure 48. Steady flow Nusselt number for in-line and perpendicular
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arrangements at Re=49,000, overall. .......... 95
Figure 49. Relative Nusselt number dependence on driving frequency
for a perpendicular arrangement with L/D=1.5, front and
back. ......................... 96
Figure 50. Relative Nusselt number dependence on driving frequency
for a perpendicular arrangement with L/D=1.5, overall. 97
Figure 51. Relative Nusselt number dependence on driving frequency
for a perpendicular arrangement with L/D=2.0, front and
back. ......................... 98
Figure 52. Relative Nusselt number dependence on driving frequency
for a perpendicular arrangement with L/D=2.0, overall. 99
Figure 53. Relative Nusselt number dependence on driving frequency
for a perpendicular arrangement with L/D=2.5, front and
back. ........................ 100
Figure 54. Relative Nusselt number dependence on driving frequency
for a perpendicular arrangement with L/D=2.5, overall. 101
List of Illustrations x