Research Papers: Gas Turbines: Turbomachinery

Investigation on the Effect of Surface Wettability on a Two-Phase Flow in a Compressor Cascade

[+] Author and Article Information
Niklas Neupert

Laboratory for Turbomachinery,
Helmut Schmidt University,
Hamburg D-22043, Germany
e-mail: Niklas.Neupert@gmx.de

Janneck Christoph Harbeck

Laboratory for Turbomachinery,
Helmut Schmidt University,
Hamburg D-22043, Germany
e-mail: Harbeck@hsu-hh.de

Franz Joos

Laboratory for Turbomachinery,
Helmut Schmidt University,
Hamburg D-22043, Germany
e-mail: Joos@hsu-hh.de

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received September 14, 2017; final manuscript received October 22, 2017; published online June 25, 2018. Editor: David Wisler.

J. Eng. Gas Turbines Power 140(10), 102603 (Jun 25, 2018) (9 pages) Paper No: GTP-17-1513; doi: 10.1115/1.4040180 History: Received September 14, 2017; Revised October 22, 2017

In recent years overspray fogging has become a powerful means for power augmentation of industrial gas turbines. Despite the positive thermodynamic effect on the cycle droplets entering the compressor increase the risk of water droplet erosion. Further deposited water leads to a higher sensitivity toward fouling due to an increased stickiness of the blades. Therefore, erosion resistant hydrophobic coatings are applied to the first stages of compressors. Although some patents claim the use of such coatings the aerodynamic impact of a different wettability is not regarded so far. This issue was addressed in the field of aerodynamic efficiency of wings in heavy rain showing higher penalty for hydrophobic coatings. In this study, the issue of a different blade surface wettability in a linear transonic compressor cascade is addressed. Different coatings are applied resulting in contact angles of 51–95 deg. The inflow Mach number was fixed at design inflow Mach number, and the inflow angle was varied over a broad range. The effect on the water film pattern is analyzed in terms of position of film breakup, rivulet width, and totally wetted surface. The performance of the cascade under two-phase flow was analyzed using laser Doppler anemometry/phase Doppler anemometry measurement technique in terms of loss coefficient based on wake momentum thickness and flow turning. It is shown that the wettability of the surface has significant effects on the film structure leading to a lower fraction of wetted surface with increasing contact angle. The influence on performance is limited to effects in the proximity of the surface and is dependent on operation point. While in design conditions hydrophilic coating show lower losses, the trend is vice-versa for off-design conditions. The data represent first experimental work on the influence of surface wettability in a droplet-laden flow supporting positive features for hydrophobic coatings in gas turbine compressors.

Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.


Balling, L. , 2011, “ Fast Cycling and Rapid Start-Up: New Generation of Plants Achieves Impressive Results,” Mod. Power Syst., 31(1), pp. 35–41. https://www.energy.siemens.com/hq/pool/hq/energy-topics/technical-papers/Fast%20cycling%20and%20rapid%20start-up.pdf
Cohen, L. S. , and Hanratty, T. J. , 1968, “ Effect of Waves at a Gas-Liquid Interface on a Turbulent Air Flow,” J. Fluid Mech., 31(03), pp. 467–479. [CrossRef]
Dunham , R. E., Jr. , Bezos, G. M. , Gentry, G. L., Jr. , and Melson, E., Jr. , 1985, “ Two-Dimensional Wind Tunnel Tests of a Transport-Type Airfoil in a Water Spray,” AIAA Paper No. 1985-258.
Marchman , J. F., III , Robertson, E. A. , and Emsley, H. T. , 1987, “ Rain Effects at Low Reynolds Number,” J. Aircr., 24(9), pp. 638–644. [CrossRef]
Brumby, R. E. , 1979, “ Wing Surface Roughness Cause and Effect,” D.C. Flight Approach, Vol. 32, McDonnell Douglas Coop., St. Louis, MO, pp. 2–7.
Hansman , R. J., Jr. , and Barsotti, M. F. , 1985, “ The Aerodynamic Effect of Surface Wetting Characteristics on a Laminar Flow Airfoil in Simulated Heavy Rain,” AIAA Paper No. 1985-260.
Dunham, R. E., Jr. , 1987, “ The Potential Influence of Rain on Airfoil Performance,” Lecture Series on the Influence of Environmental Factors on Aircraft Wing Performance, Rhode-Saint-Genese, Belgium, Feb. 16–20.
Thompson, B. E. , and Jang, J. , 1996, “ Aerodynamic Efficiency of Wings in Rain,” J. Aircr., 33(6), pp. 1047–1053. [CrossRef]
Kurz, R. , and Brun, K. , 2012, “ Fouling Mechanisms in Axial Compressors,” ASME J. Eng. Gas Turbines Power, 134(3), p. 032401. [CrossRef]
Williams, J. , and Young, J. B. , 2007, “ Movement of Deposited Water on Turbomachinery Rotor Blade Surfaces,” ASME J. Turbomach., 129(2), pp. 394–403. [CrossRef]
Neupert, N. , Gomaa, H. , Joos, F. , and Weigand, B. , 2016, “ Investigation and Modeling of Two Phase Flow Through a Compressor Stage: Analysis of Film Breakup,” Eur. J. Mech.-B/Fluids, 61, pp. 279–288. [CrossRef]
Gomaa, H. , 2014, “ Modeling of Liquid Dynamics in Spray Laden Compressor Flows,” Ph.D. thesis, University Stuttgart, Stuttgart, Germany.
Simon, A. , Marcelet, M. , Hérard, J. , Dorey, J. M. , and Lance, M. , 2016, “ A Model for Liquid Film in Steam Turbines,” ASME Paper No. GT2016-56148.
Hammitt, F. G. , Krzeczkowski, S. , and Krzyanowski, J. , 1981, “ Liquid Film and Droplet Stability Consideration as Applied to Wet Steam Flow,” Forschung Im Ingenieurwesen A, 47(1), pp. 1–14. [CrossRef]
Zhang, K. , 2015, “ An Experimental Study of Wind-Driven Surface Water Transport Process Pertinent to Aircraft Icing,” Ph.D. thesis, Iowa State University, Ames, IA. https://lib.dr.iastate.edu/etd/14465/
Itoh, M. , and Matsuno, S. , 2014, “ Scale Effect on Liquid Film Formation in a Prefilming Type Air-Blast Atomizer,” 26th International Conference on Liquid Atomization and Spray Systems (ICLASS), Bremen, Deutschland, pp. 1–12.
Al-Khalil, K. M. , Keith , T. G., Jr. , and De Witt, K. J. , 1990, “ Development of an Anti-Icing Runback Model,” AIAA Paper No. 90-759.
Lieblein, S. , 1959, “ Loss and Stall Analysis of Compressor Cascades,” J. Basic Eng., 81, pp. 387–400.
Aungier, R. H. , 2003, Axial-Flow Compressor: A Strategy for Aerodynamic Design and Analysis, ASME, New York.
Ober, B. , 2013, “ Experimental Investigation on the Aerodynamic Performance of a Compressor Cascade in Droplet Laden Flow,” Ph.D. thesis, Helmut-Schmidt-University, Hamburg, Germany.
Canny, J. , 1986, “ A Computational Approach to Edge Detection,” IEEE Trans. Pattern Anal. Mach. Intell., 8(6), pp. 679–698. [CrossRef] [PubMed]
Neupert, N. , Harbeck, J. C. , and Joos, F. , 2017, “ An Experimentally Derived Model to Predict the Water Film in a Compressor Cascade With Droplet Laden Flow,” ASME Paper No. GT2017-64121.
Neumann, A. W. , and Good, R. J. , 1979, “ Techniques of Measuring Contact Angles,” Surface and Colloid Science, Vol. 11, R. J. Good and R. R. Stromberg , eds., Springer, Boston, MA, pp. 31–91. [CrossRef]
Thompson, B. E. , Jang, J. , and Dion, J. L. , 1995, “ Wing Performance in Moderate Rain,” J. Aircr., 32(5), pp. 1034–1039. [CrossRef]
Eisfeld, T. , 2011, “ Experimentelle Untersuchung Der Aerodynamik Einer Mit Wassertropfen Beladenen Luftströmung in Einem Ebenen Verdichtergitter,” Ph.D. thesis, Helmut-Schmidt-University, Hamburg, Germany.


Grahic Jump Location
Fig. 1

Definition of impact region

Grahic Jump Location
Fig. 2

Image of the water film pattern

Grahic Jump Location
Fig. 3

Assumed shape of rivulets and equilibrium of forces at the contact line

Grahic Jump Location
Fig. 4

Illustration of the wind tunnel

Grahic Jump Location
Fig. 5

Inlet droplet spectrum

Grahic Jump Location
Fig. 6

Measurement setup nonintrusive method

Grahic Jump Location
Fig. 7

Results of the image processing: (a) resulting image from [11] and (b) final Image including the rivulets

Grahic Jump Location
Fig. 8

Results of the contact angle measurement: (a) gray scale image of the droplet and (b) final image including the drop shape and the tangent in the triple point

Grahic Jump Location
Fig. 9

Validation of the contact angle measurement

Grahic Jump Location
Fig. 10

Experimentally derived 3D water patterns for all contact angles and α = 2 deg

Grahic Jump Location
Fig. 11

Comparison of the film breakup position

Grahic Jump Location
Fig. 12

Comparison of the rivulet width

Grahic Jump Location
Fig. 13

Comparison of the wetted surfaces

Grahic Jump Location
Fig. 14

Deflection Δβ over the incidence angle α for all coatings in comparison to dry airflow (black)

Grahic Jump Location
Fig. 15

Loss coefficient ω over the incidence angle α for all coatings in comparison to dry airflow (black)

Grahic Jump Location
Fig. 16

Noramalized velocity ratio (w2/w1)/(w2/w1)¯ for all coatings for α = 0 deg and α = 4 deg: (a) α = 0 deg and (b) α = 4 deg



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In