Research Papers

Improved Accuracy in Jet Impingement Heat Transfer Experiments Considering the Layer Thicknesses of a Triple Thermochromic Liquid Crystal Coating

[+] Author and Article Information
Alexandros Terzis

Group of Thermal Turbomachinery (GTT),
École Polytechnique Fédérale
de Lausanne (EPFL),
Lausanne CH-1015, Switzerland
e-mail: alexandros.terzis@me.com

Stavros Bontitsopoulos, Peter Ott

Group of Thermal Turbomachinery (GTT),
École Polytechnique Fédérale
de Lausanne (EPFL),
Lausanne CH-1015, Switzerland

Jens von Wolfersdorf

Institute of Aerospace Thermodynamics (ITLR),
University of Stuttgart,
Pfaffenwaldring 31,
Stuttgart D-70569, Germany

Anestis I. Kalfas

Laboratory of Fluid Mechanics
and Turbomachinery (LFMT),
Aristotle University of Thessaloniki (AUTH),
Thessaloniki GR-54124, Greece

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received May 13, 2015; final manuscript received September 16, 2015; published online November 3, 2015. Assoc. Editor: Cengiz Camci.

J. Turbomach 138(2), 021003 (Nov 03, 2015) (10 pages) Paper No: TURBO-15-1094; doi: 10.1115/1.4031786 History: Received May 13, 2015; Revised September 16, 2015

This paper examines the applicability of a triple layer of thermochromic liquid crystals (TLCs) for the determination of local heat transfer coefficients using the transient liquid crystal (LC) technique. The experiments were carried out in a narrow impingement channel, typically used for turbine blade cooling applications. Three types of narrow bandwidth LCs (1 °C range) of 35 °C, 38 °C, and 41 °C were individually painted on the target plate of the cooling cavity and the overall paint thickness was accurately determined with an integral coating thickness gauge. The 1D transient heat conduction equation is then implicitly solved for each individual TLC layer on its realistic depth on the painted surface. Local heat transfer coefficients are therefore calculated three times for the same location in the flow improving the measurement accuracy, especially at regions where the LC detection times are too short (stagnation points) or too long (wall-jet regions). The results indicate that if multiple LC layers are used and the paint thickness is not considered, the heat transfer coefficients can be significantly underestimated.

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Camci, C. , Kim, K. , Hippensteele, S. A. , and Poinsatte, P. E. , 1993, “ Evaluation of a Hue Capturing Based Transient Liquid Crystal Method for High-Resolution Mapping of Convective Heat Transfer on Curved Surfaces,” ASME J. Heat Transfer, 115(2), pp. 311–318. [CrossRef]
Hippensteele, S. A. , and Poinsatte, P. E. , 1993, “ Transient Liquid Crystal Technique Used to Produce High-Resolution Convective Heat Transfer Coefficient Maps,” NASA Lewis Research Center, Cleveland, OH, NASA Technical Report No. NASA TM-106083.
Baughn, J. W. , 1995, “ Liquid Crystal Methods for Studying Turbulent Heat Transfer,” Int. J. Heat Fluid Flow, 16(5), pp. 365–375. [CrossRef]
Ireland, P. T. , and Jones, T. V. , 2000, “ Liquid Crystal Measurements of Heat Transfer and Surface Shear Stress,” IOP Meas. Sci. Technol., 11(7), pp. 969–986. [CrossRef]
Ekkad, S. V. , and Han, J.-C. , 2000, “ A Transient Liquid Crystal Thermography Technique for Gas Turbine Heat Transfer Measurements,” IOP Meas. Sci. Technol., 11(7), pp. 957–968. [CrossRef]
Carslaw, H. S. , and Jaeger, J. C. , 1986, Conduction of Heat in Solids, 2nd ed., Oxford Science Publications, Clarendon Press, Oxford, UK.
Pountney, O. , Cho, G. , Lock, G. D. , and Owen, J. M. , 2012, “ Solutions of Fourier's Equation Appropriate for Experiments Using Thermochromic Liquid Crystal,” Int. J. Heat Mass Transfer, 55(21–22), pp. 5908–5915. [CrossRef]
Poser, R. , and von Wolfersdorf, J. , 2011, “ Liquid Crystal Thermography for Transient Heat Transfer Measurements in Complex Internal Cooling Systems,” ASME J. Heat Transfer, 42(2), pp. 181–197.
Poser, R. , Ferguson, J. R. , and von Wolfersdorf, J. , 2009, “ Temporal Signal Processing and Evaluation of Thermochromic Liquid Crystal Indications in Transient Heat Transfer Experiments,” 8th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics (ETC8), Graz, Austria, Mar. 23–27, pp. 785–795.
Vogel, G. , and Weigand, B. , 2001, “ A New Evaluation Method for Transient Liquid Crystal Experiments,” ASME 35th National Heat Transfer Conference (NHTC01), Anaheim, CA, June 10–12, Paper No. NHTC2001-20250.
Terzis, A. , 2014, “ Detailed Heat Transfer Distributions of Narrow Impingement Channels for Integrally Cast Turbine Airfoils,” Ph.D. thesis, Swiss Federal Institute of Technology, EPFL, Lausanne, Switzerland, Thesis No. 6177.
Goldstein, R. J. , and Behbahani, A. I. , 1982, “ Impingement of a Circular Jet With and Without Cross Flow,” Int. J. Heat Mass Transfer, 25(9), pp. 1377–1382. [CrossRef]
Goldstein, R. J. , and Timmers, J. F. , 1982, “ Visualization of Heat Transfer From Arrays of Impinging Jets,” Int. J. Heat Mass Transfer, 25(12), pp. 1857–1868. [CrossRef]
Huang, L. , and El-Genk, M. S. , 1994, “ Heat Transfer of an Impinging Jet on a Flat Surface,” Int. J. Heat Mass Transfer, 37(13), pp. 1915–1923. [CrossRef]
O'Donovan, T. S. , and Murray, D. B. , 2007, “ Jet Impingement Heat Transfer–Part II: A Temporal Investigation of Heat Transfer and Local Fluid Velocities,” Int. J. Heat Mass Transfer, 50(17–18), pp. 3302–3314. [CrossRef]
Lee, D. H. , Song, J. , and Chan, J. M. , 2004, “ The Effects of Nozzle Diameter on Impinging Jet Heat Transfer and Fluid Flow,” ASME J. Heat Transfer, 126(4), pp. 554–557. [CrossRef]
Baughn, J. W. , and Shimizu, S. , 1989, “ Heat Transfer Measurements From a Surface With Uniform Heat Flux and an Impinging Jet,” ASME J. Heat Transfer, 111(4), pp. 1096–1098. [CrossRef]
Lytle, D. , and Webb, B. W. , 1994, “ Air Jet Impingement Heat Transfer at Low Nozzle-Plate Spacings,” Int. J. Heat Mass Transfer, 37(12), pp. 1687–1697. [CrossRef]
Baughn, J. W. , Mayhew, J. E. , Anderson, M. R. , and Butler, R. J. , 1998, “ A Periodic Transient Method Using Liquid Crystals for the Measurement of Local Heat Transfer Coefficients,” ASME J. Heat Transfer, 120(3), pp. 772–777. [CrossRef]
Wang, Z. , Ireland, P. T. , and Jones, T. V. , 1995, “ An Advanced Method of Processing Liquid Crystal Video Signals From Transient Heat Transfer Experiments,” ASME J. Turbomach., 117(1), pp. 184–189. [CrossRef]
Talib, A. R. A. , Neely, A. J. , Ireland, P. T. , and Mullender, A. J. , 2004, “ A Novel Liquid Crystal Image Processing Technique Using Multiple Gas Temperature Steps to Determine Heat Transfer Coefficient Distribution and Adiabatic Wall Temperature,” ASME J. Turbomach., 126(4), p. 587. [CrossRef]
Ling, J. P. C. W. , Ireland, P. T. , and Turner, L. , 2004, “ A Technique for Processing Transient Heat Transfer, Liquid Crystal Experiments in the Presence of Lateral Conduction,” ASME J. Turbomach., 126(2), pp. 247–258. [CrossRef]
Waidmann, C. , Poser, R. , and von Wolfersdorf, J. , 2013, “ Application of Thermochromic Liquid Crystal Mixtures for Transient Heat Transfer Measurements,” 10th European Conference on Turbomachinery Fluid Mechanics and Thermodynamics (ETC10), Lappeenranta, Finland, Apr. 15–19, pp. 685–696.
Schulz, S. , Brack, S. , Terzis, A. , von Wolfersdorf, J. , and Ott, P. , 2015, “ On the Effects of Coating Thickness in Transient Heat Transfer Experiments Using Thermochromic Liquid Crystals,” Exp. Therm. Fluid Sci., 70, pp. 196–207. [CrossRef]
Terzis, A. , Ott, P. , von Wolfersdorf, J. , Weigand, B. , and Cochet, M. , 2014, “ Detailed Heat Transfer Distributions of Narrow Impingement Channels for Cast-In Turbine Airfoils,” ASME J. Turbomach., 136(9), p. 091011. [CrossRef]
Park, J. , Goodro, M. , Ligrani, P. , Fox, M. , and Moon, H.-K. , 2007, “ Separate Effects of Mach Number and Reynolds Number on Jet Array Impingement Heat Transfer,” ASME J. Turbomach., 129(2), pp. 269–280. [CrossRef]
Fergason, J. L. , 1964, “ Liquid Crystals,” Sci. Am., 211(2), pp. 76–85. [CrossRef]
Fergason, J. L. , 1968, “ Liquid Crystals in Nondestructive Testing,” Appl. Opt., 7(9), pp. 1729–1737. [CrossRef] [PubMed]
Hallcrest, 2014, “ TLC Products for Use in Research and Testing Applications,” LCR Hallcrest Research and Testing Products, Glenview, IL.
Heidmann, J. D. , 1994, “ Determination of a Transient Heat Transfer Property of Acrylic Using Thermochromic Liquid Crystals,” NASA Lewis Research Center, Cleveland, OH, Report No. NASA-TM-106541.
Kwak, J. S. , 2008, “ Comparison of Analytical and Superposition Solutions of the Transient Liquid Crystal Technique,” AIAA J. Thermophys. Heat Transfer, 22(2), pp. 290–295. [CrossRef]
Terzis, A. , von Wolfersdorf, J. , Weigand, B. , and Ott, P. , 2012, “ Thermocouple Thermal Inertia Effects on Impingement Heat Transfer Experiments Using the Transient Liquid Crystal Technique,” IOP Meas. Sci. Technol., 23(11), p. 115303. [CrossRef]
Ireland, P. T. , and Jones, T. V. , 1987, “ The Response Time of a Surface Thermometer Employing Encapsulated Thermochromic Liquid Crystals,” J. Phys. E: Sci. Instrum., 20(10), pp. 1195–1199. [CrossRef]
Terzis, A. , Wagner, G. , von Wolfersdorf, J. , Ott, P. , and Weigand, B. , 2014, “ Hole Staggering Effect on the Cooling Performance of Narrow Impingement Channels Using the Transient Liquid Crystal Technique,” ASME J. Heat Transfer, 136(7), p. 071701. [CrossRef]
Bouchez, J. P. , and Goldstein, R. J. , 1975, “ Impingement Cooling From a Circular Jet in a Cross Flow,” Int. J. Heat Mass Transfer, 18(6), pp. 719–730. [CrossRef]
Florschuetz, L. W. , Truman, C. R. , and Metzger, D. E. , 1981, “ Streamwise Flow and Heat Transfer Distributions for Jet Array Impingement With Crossflow,” ASME J. Heat Transfer, 103(2), pp. 337–342. [CrossRef]
Terzis, A. , Ott, P. , Cochet, M. , von Wolfersdorf, J. , and Weigand, B. , 2015, “ Effect of Varying Jet Diameter on the Heat Transfer Distributions of Narrow Impingement Channels,” ASME J. Turbomach., 137(2), p. 021004. [CrossRef]
Yan, Y. , and Owen, J. M. , 2002, “ Uncertainties in Transient Heat Transfer Measurements With Liquid Crystal,” Int. J. Heat Fluid Flow, 23(1), pp. 29–35. [CrossRef]


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Fig. 1

Local Nusselt number distributions under a single round impingement jet. Adopted from Terzis [11].

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Fig. 2

Experimental setup: (a) 3D representation of the test facility and (b) schematic representation of the test model

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Fig. 3

Schematic representation of the different TLC layers

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Fig. 4

Hot gas temperature extraction for different thermocouples

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Fig. 5

Overall paint thickness measurements

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Fig. 6

LC calibration test rig

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Fig. 7

Color-play of the TLC during calibration procedure: (a) 34.65 °C, (b) 34.71 °C, (c) 34.80 °C, (d) 34.85 °C, (e) 34.91 °C, (f) 35.01 °C, (g) 35.10 °C, (h) 35.15 °C, (i) 35.21 °C, and (j) 35.27 °C

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Fig. 8

Green channel intensity calibration curves

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Fig. 9

Video frames after the initiation of the heating step with base intensity level removed: (a) t = 0 s, reference image, (b) t = 2.2 s, TLC35 at stagnation regions, (c) t = 4.5 s, TLC38 at stagnation regions, (d) t = 7.5 s, TLC41 at stagnation regions, and (e) t = 15 s

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Fig. 10

Normalized and filtered green intensity histories at two different locations in the flow domain: (a) stagnation points → short indication times → high heat transfer and (b) wall-jet regions → late indication times → low heat transfer

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Fig. 11

Time matrices at ReD = 37,500 for all TLC layers: (a) t for TLC35 and z = 16 μm, (b) t for TLC38 and z = 27 μm, and (c) t for TLC41 and z = 38 μm

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Fig. 12

Heat transfer coefficient (h/href) surface contours at ReD = 37,500 for all TLC layers. href = 350 W/(m2K): (a) TLC35 and z = 16 μm, (b) TLC38 and z = 27 μm, and (c) TLC41 and z = 38 μm.

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Fig. 13

Local heat transfer coefficients on the channel centerline (y = 0) for all TLC layers, ReD = 37,500

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Fig. 14

Effect of paint thickness on the evaluation of heat transfer coefficients for all examined experiments

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Fig. 15

Effect of paint thickness on the evaluation of heat transfer coefficients for all examined experiments

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Fig. 16

Individual uncertainty terms for all independent variables as a function of time. ReD = 27,500, z = 28 μm, and θ = 0.56.

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Fig. 17

Effect of coating thickness on the uncertainty term of z at the same θ = 0.46

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Fig. 18

Probability density functions of the overall heat transfer coefficient. h¯=255.7  ± 33.1 W/(m2 K).



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