An experimental study to determine the convective heat transfer coefficient from castings made from ice-roughened plates is reported. A corresponding topic, 'Measurements of the Convective Heat Transfer Coefficient from Ice Roughened Surfaces in Parallel and Accelerated Flows,' is presented

DeWitt, Keneth J.

English

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NASA-CR-202?20
FINAL TECHNICAL REPORT
FOR NASA GRANT NAG 3-1796
Entitled
NUMERICAL SIMULATION OF INTERNAL HEAT TRANSFER PHENOMENA OCCURRING
DURING DE-ICING OF AIRCRAFT COMPONENTS
Prepared for
NASA Lewis Research Center
Cleveland, Ohio 44135
J
by
Principal Investigator:
Kenneth J. De Witt
Distinguished University Professor
Department of Chemical Engineering
The University of Toledo
Toledo, Ohio 43606
Submitted December, 1996
for the period
10-6-95 to 9-30-96
https://ntrs.nasa.gov/search.jsp?R=19970003560 2020-06-16T03:37:35+00:00Z
FINAL REPORT for NAG 3-1796
The numerical simulation of the internal heat transfer
phenomena occurring during anti-icing or de-icing of a
layered aircraft or rotor blade with an electrothermal heat
source has been a subject of intense research by University
of Toledo faculty and graduate students since 1980. The
present grant involved an experimental study to determine
the convective heat transfer coefficient from castings made
from ice-roughened flat plates. The convective heat
transfer coefficient between accreted ice and the
surrounding environment has long been known to be the key
parameter in the energy balance that predicts the continued
transient growth and shape of the resulting ice. This
effort was initiated by the inability of the current ice
prediction codes to accurately model glaze ice shapes. This
was an intense effort in which University of Toledo faculty
members and a doctoral student constructed the necessary
models and ran wind tunnel tests using electrothermal
heaters to measure the convective heat transfer
coefficients. In a previous final report, 63 publications
related to the work done by the University of Toledo de-
icing group were listed. The present final report lists
below the three publications resulting from the current
work, which are available in the open literature. In
addition, the final Ph.D. dissertation is attached. All of
this material has been provided to the grant technical
monitor.
Dukhan, N., G. J. Van Fossen, K. C. Masiulaniec and K. J.
De Witt, "Experimental Technique and Assessment for
Measuring the Convective Heat Transfer from Natural Ice
Accretions," 33rd Aerospace Sciences Meeting, Reno,
Nevada, 1/95, Paper No. AIAA-95-0537, 24 pgs.
Dukhan, N., G. J. Van Fossen, K. C. Masiulaniec and K. J.
De Witt, "Convective Heat Transfer from Castings of Ice
Roughened Surfaces in Horizontal Flight," American
Helicopter Society International Icing Symposium,
Montreal, Canada, 9-95, Conference Proceedings, pp.
127-140.
Dukhan, N., G. J. Van Fossen, K. C. Masiulaniec and K. J.
De Witt, "Convective Heat Transfer Coefficients from
Various Types of Ice Roughened Surfaces in Parallel and
Accelerating Flow," 34rd Aerospace Sciences Meeting,
Reno, Nevada, 1/96, Paper No. AIAA-96-0867, 20 pgs.
A Dissertation
Entitled
MEASUREMENTS OF THE CONVECTIVE HEAT TRANSFER
COEFFICIENT FROM ICE ROUGHENED SURFACES IN
PARALLEL AND ACCELERATED FLOWS
by
Nihad Abed-eI-Fattah Dukhan
as partial fulfillment of the requirements of
the Doctor of Philosophy Degree in
Engineering Science
__. Masiulaniec
"1I 1'/'*_
Co-advisor K._. DeWitt
Graduate School
The University of Toledo
December 1996
THE UNIVERSITY OF TOLEDO
.....................
COLLEGE OF ENGINEERING
August 23. 1996
Date
I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY
SUPERVISION BY NIHAD DUKHAN
ENTITLED Measurements of the Convective Heat Transfer Coefficient from
o Ice Rouqhened Surfaces in Parallel and Accelerated Flows
BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
THE DEGREE OF DOCTOR OF PHILOSOPHY IN ENGINEERING SCIENCE
THESIS ADVISORS K.C. Masiulaniec and K.J. DeWitt
CHAIRMAN OF DISCIPLINE A. A. Afjeh
Recommendation concurred
-t./
Committee
on
Final Examination
An Abstract of
Measurements of the Convective Heat Transfer Coefficient from
Roughened Surfaces in Parallel and Accelerated Flows
Ice
Nihad Dukhan
Submitted in partial fulfillment of the requirements of
the Doctor of Philosophy Degree in
Engineering Science
The University of Toledo
December 1996
Values for the heat transfer coefficient from different ice roughened
surfaces in parallel and accelerated flows were experimentally sought for use in
de-icing computer codes. Aluminum castings of different ice accretions in an
icing wind tunnel were obtained from which heat transfer models were
constructed. Each model was a large composite of heat flux gages to which
heat was supplied from the bottom using themofoil heating elements. The heat
supplied to each gage was allowed to convect upward from the rough surface to
an air stream in a dry wind tunnel. Other heat losses were eliminated and each
gage was insulated from surrounding ones. Average values of the heat transfer
coefficient were computed from an energy balance for each gage with the
known electrical power of the heating elements.
Results were obtained for local Reynolds numbers ranging from 5.3X104
to l ,3X106, and for tilt angles of 0 ° , 14 °,23 °,32 °,and 41 ° . The results were in
general qualitative agreement with those of uniform roughness with the different
behaviors being more drastic in the case of stochastic roughness. The Stanton
iv
number for random roughness was higher than that for uniform roughness and
was directly proportional to both roughness element height and area increase
and inversely proportional to spacing. The effect of free-stream velocity
diminished at high enough Reynolds number and the Stanton numbers
collapsed onto a single curve. Acceleration caused Stanton number to start at
lower values close to the leading edge, Stanton numbers then increased as the
flow accelerated along each tilted model. In the fully rough region and for
parallel and mildly accelerated flows, up to 23 °, Stanton number was a function
of Reynolds number only and followed a power law. The multiplier and the
exponent of Reynolds number in this power law were found to correlate well
w
with the newly defined parameter, Index of Random Roughness, and the
roughness height, respectively.
V
TABLE OF CONTENTS
ACKNOWLEDGMENT ........................................................................................... ii
ABSTRACT ............................................................................................................... iv
TABLE OF CONTENTS ..................................................................................... vi
D
NOMENCLATURE ................................................................................................ xii
LIST OF FIGURES .............................................................................................. xv
LIST OF PLATES ............................................................................................ xxviii
LIST OF TABLES .............................................................................................. xxxi
CHAPTER 1 INTRODUCTION ................................................................. 1
1.1 Th e Roughness Problem ....................................... 1
1.2 Early Studies ............................................................... 2
1.3 Studies at Stanford University .......................... 8
1.4 Numerical Solution and the Discrete Element
Method ..........................................................................10
1.5 More Recent Studies ............................................. 12
1.6 Ice-Roughness Studies ........................................ 14
vi
1.7 The Scope of the Present Study ..................... 16
CHAPTER 2 INVESTMENT CASTING .............................................. 19
2.1 An Overview of the Investment Casting
Process ........................................................................ 19
2.2 Investment Casting of Ice ................................... 25
2.3 Obtaining Aluminum Castings of Natural Ice
Shapes ......................................................................... 26
2.3-A Ice Growing .................................................. 26
2.3-B Investment Casting ................................... 27
CHAPTER 3 EXPERIMENTAL METHODS ...................................... 65
3.1 Model Construction ................................................ 65
3.1-A Axial Free-Stream Velocity
Measurements Model ............................. 65
3.1-B Smooth Heat Transfer Model .............. 66
3.1-C Roughness Heat Transfer Model ....... 69
3.1-D Saddle ............................................................ 70
3.2 Wind Tunnel .............................................................. 71
3.3 Data Acquisition system ...................................... 72
3.4 Data Collection ........................................................ 74
3.5 Data Reduction ........................................................ 75
vii
6.1 Comparisons of the Eight Roughness
Models ........................................................................ 227
6.1-A Unaccelerated Cases ........................... 227
6.2-B Accelerated Case, e = 14 ° .................. 230
6.2-C Accelerated Case, e = 23 ° ................. 231
6.2-D Accelerated Case, e = 32 ° ................. 232
6.2-E Accelerated Case, e = 41 ° . ................. 233
6.2 Comparisons with Other Studies .................. 234
6.2-A Unaccelerated Cases ........................... 235
6.2-B Accelerated Cases ................................. 242
CHAPTER 7 CORRELATIONS .......................................................... 284
7.1 Unaccelerated Case .......................................... 285
7.1-A Correlations of Stanton Number ..... 285
7.1-B Correlations of the
Constants 'a' and 'm' ............................ 286
7.2 Accelerated Cases ............................................. 288
7.2-A e=14 ° ............................................................. 288
7.2-B e=23 ° .......................................................... :.. 288
7.3 Concluding Remarks ......................................... 289
X
CHAPTER 8 CONCLUSIONS AND RECOMMENDATIONS .... 309
REFERENCES
APPENDIX I
APPENDIX II
................. ,°oo ............ °°°°°o.°° ..... ° .... o°o°oo°• ..................... • .... °°_o°•°°o°°° 313
UNCERTAINTY ANALYSIS .................................... 319
TABULATION OF EXPERIMENTAL DATA ..... 324
I1.1 Axial Free-Stream Velocity ...................................... 324
11.10
11.2 Smooth Model - Stanton Numbers ....................... 326
11.3 Roughness Model No, 1 - Stanton Numbers ... 330
11.4 Roughness Model No. 2 - Stanton Numbers ... 334
11.5 Roughness Model No, 3 - Stanton Numbers ..o 338
11.6 Roughness Model No, 4 - Stanton Numbers ... 342
11.7 Roughness Model No. 5 - Stanton Numbers ... 346
11.8 Roughness Model No, 6 - Stanton Numbers ... 350
11.9 Roughness Model No. 7 - Stanton Numbers o.. 354
Roughness Model No. 8 - Stanton Numbers ... 358
I1.11 Correlations' Constants ........................................... 362
×i


Numerical Simulation of Internal Heat Transfer Phenomena Occurring During De-Icing of Aircraft Components

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