A new method of processing the liquid crystal color change data obtained from transient heat transfer experiments is presented. The approach uses the full-intensity history recorded during an experiment to obtain an accurate measurement of the surface heat transfer coefficient at selected pixels. Results are presented for a model of a turbine blade cooling passage with combined ribs and film cooling holes. The implementation of the technique and the advantages to be gained from its application are discussed.

Issue Section:
Research Papers
Topics:
Liquid crystals, Signals, Transient heat transfer, Cooling, Film cooling, Heat transfer coefficients, Turbine blades
1.
Akino, N., Kunugi, T., Ueda, M., and Kurosawa, X., 1988, “Liquid Crystal Thermometry Based on Automatic Color Evaluation and Applications to Measure Turbulent Heat Transfer,” Transport Phenomena in Turbulent Flows, Hemisphere, Washington, DC, pp. 807–820.
2.
Baughn
J. W.
,
Ireland
P. T.
,
Jones
T. V.
, and
Saniei
N.
,
1989
, “
A Comparison of the Transient and Heated-Coating Methods for the Measurement of Local Heat Transfer Coefficients on a Pin Fin
,”
ASME Journal of Heat Transfer
, Vol.
111
, pp.
877
–
881
.
3.
Camci
C.
,
Kim
K.
, and
Hippensteele
S. A.
,
1992
, “
A New Hue Capturing Technique for Quantitative Interpretation of Liquid Crystal Images Used in Convective Heat Transfer Studies
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
114
, pp.
765
–
775
.
4.
Clifford, R. J., Jones, T. V., and Dunne, S. T., 1983, “Techniques for Obtaining Detailed Heat Transfer Coefficient Measurements Within Gas Turbine Blade and Vane Cooling Passages,” ASME Paper No. 83-GT-58.
5.
Davenport, R., 1989, “Innovative Use of Thermochromic Liquid Crystals for Turbine Blade Internal Cooling Passage Flow Visualisation and Heat Transfer Measurements,” Proceedings of European Propulsion Forum, Modern Techniques and Developments in Engine and Component Testing, Royal Aeronautical Society, 16.1–16.5
6.
Gill
P. E.
, and
Murray
W.
,
1972
, “
Quasi-Newton Methods for Unconstrained Optimization
,”
Journal of the Institute of Mathematics and Its Applications
, Vol.
9
, pp.
91
–
108
.
7.
Hippensteele, S. A., and Russell, L. M., 1984, “Use of a Liquid-Crystal, Heater-Element Composite for Quantitative, High-Resolution Heat Transfer Coefficients on a Turbine Airfoil, Including Turbulence and Surface Roughness Effects,” NASA TM 87355.
8.
Ireland, P. T., and Jones, T. V., 1986, “Detailed Measurements of Heat Transfer on and Around a Pedestal in Fully Developed Passage Flow,” Proceedings of 8th International Heat Transfer Conference, Hemisphere, Washington, DC, pp. 975–980.
9.
Shen, J. R., Wang, Z., Ireland, P. T., and Jones, T. V., 1994, “Heat Transfer Enhancement Within a Turbine Blade Cooling Passage Using Ribs and Combinations of Ribs With Film Cooling Holes,” ASME Paper No. 94-GT-232; to be published in the Transactions of the ASME.
10.
Vedula, R. J., and Metzger, D. E., 1991, “A Method for the Simultaneous Determination of Local Effectiveness and Heat Transfer Distributions in Three-Temperature Convective Situations,” ASME Paper No. 91-GT-345.
11.
Wang, Z., Ireland, P. T., and Jones, T. V., 1990, “A Technique for Measuring Convective Heat Transfer at Rough Surfaces,” ASME Paper No. 90-GT-300.
12.
Wang, Z., 1991, “The Application of Thermochromic Liquid Crystals to Detailed Turbine Blade Cooling Measurements,” D. Phil Thesis, Department of Engineering Science, University of Oxford, United Kingdom.
13.
Watt, A., 1989, Three Dimensional Computer Graphics, Addison Wesley, Chap. 14.
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