Journal of Coatings Technology and Research

, Volume 12, Issue 5, pp 915–920 | Cite as

Local heat transfer characteristics of a slot nozzle array for batch drying of thin films under industrial process conditions

  • Michael BaunachEmail author
  • Stefan Jaiser
  • Philipp Cavadini
  • Philip Scharfer
  • Wilhelm Schabel


For optimizing the drying process of thin functional films, knowledge of the relevant influencing parameters is needed. One paramount parameter for design of experimental conditions and the accurate interpretation of experimental data is the heat transfer coefficient inside a dryer. Information on the heat transfer in a dryer also facilitates a reliable transfer of results obtained in laboratory set-ups to industrial production. In this work, the heat transfer in a batch drying set-up with an array of slot nozzles is investigated. The measurement arrangement consists of a heat flux sensor mounted on the surface of a temperature-controlled plate. For validation of this arrangement, heat transfer measurements with a single round nozzle were compared to transient heat transfer experiments using thermochromic liquid crystals. The data measured in the batch drying set-up show a periodically homogenous distribution of heat transfer coefficients for the investigated 16 nozzles. This gives the possibility to dry thin films with a coating length of up to 800 mm in the set-up at constant conditions along the coating length. A prerequisite is a periodical movement with an amplitude of at least one nozzle-to-nozzle spacing.


Heat transfer Mass transfer Drying Coating Impingement dryer 



The present work was supported by the German Research Foundation (DFG, research Grant SCHA 1266/9-1) and the European Union (FP7-NMP, Grant agreement 608931). Determination of the TLC data used for validation of the measurement arrangement was funded by the German Research Foundation (DFG, research Grant SCHA 1266/8-1). The authors would like to thank M. Zimmermann, S. Schneider, and T. Schick for their help with the experimental work and the Project Competence E at KIT for support.


  1. 1.
    Schmidt-Hansberg, B, Sanyal, M, Klein, MFG, Pfaff, M, Schnabel, N, Jaiser, S, Vorobiev, A, Müller, E, Colsmann, A, Scharfer, P, Gerthsen, D, Lemmer, U, Barrena, E, Schabel, W, “Moving Through the Phase Diagram: Morphology Formation in Solution Cast Polymer-Fullerene Blend Films for Organic Solar Cells.” ACS Nano, 5 (11) 8579–8590 (2011)CrossRefGoogle Scholar
  2. 2.
    Buss, F, Roberts, CC, Crawford, KS, Peters, K, Francis, LF, “Effect of Soluble Polymer Binder on Particle Distribution in a Drying Particulate Coating.” J. Colloid Interface Sci., 359 (1) 112–120 (2011)CrossRefGoogle Scholar
  3. 3.
    Rajala, P, Milosavljevic, N, Kiiskinen, H, Hendrickson, M, “The Effect of the Impingement Air Drying on Print Mottle and Other Coated Paper Properties.” Appl. Thermal Eng., 24 (17–18) 2527–2536 (2004)CrossRefGoogle Scholar
  4. 4.
    O’Donovan, TS, Murray, DB, “Jet Impingement Heat Transfer—Part I: Mean and Root-Mean-Square Heat Transfer and Velocity Distributions.” Int. J. Heat Mass Transf., 50 (17–18) 3291–3301 (2007)CrossRefGoogle Scholar
  5. 5.
    Martin, H, “Heat and Mass Transfer Between Impinging Gas Jets and Solid Surfaces.” In: Hartnett, JP, Irvine, TF (eds.) Advances in Heat Transfer, pp. 1–60. Elsevier, Amsterdam (1977)Google Scholar
  6. 6.
    Schabel, W, Martin, H, “G10 Impinging Jet Flow Heat Transfer.” In: VDI Heat Atlas, pp. 745–752. Springer, Berlin (2010)Google Scholar
  7. 7.
    Cavadini, P, Scharfer, P, Schabel, W, “Investigation of Heat Transfer Within an Array of Impinging Jets with Local Extraction.” Proceedings of the 15th International Heat Transfer Conference, Kyoto, Japan, August 2014Google Scholar
  8. 8.
    Yan, X, A Preheated-Wall Transient Method Using Liquid Crystals for the Measurement of Heat Transfer on External Surfaces and in Ducts. University of California, Davis (1993)Google Scholar
  9. 9.
    Katti, V, Prabhu, S, “Experimental Study and Theoretical Analysis of Local Heat Transfer Distribution Between Smooth Flat Surface and Impinging Air Jet from a Circular Straight Pipe Nozzle.” Int. J. Heat Mass Transf., 51 (17–18) 4480–4495 (2008)CrossRefGoogle Scholar
  10. 10.
    Schlünder, EU, Gnielinski, V, “Wärme- und Stoffübertragung zwischen Gut und aufprallendem Düsenstrahl.” Chemie Ingenieur Technik, 39 (9–10) 578–584 (1967)CrossRefGoogle Scholar

Copyright information

© American Coatings Association 2015

Authors and Affiliations

  • Michael Baunach
    • 1
    Email author
  • Stefan Jaiser
    • 1
  • Philipp Cavadini
    • 1
  • Philip Scharfer
    • 1
  • Wilhelm Schabel
    • 1
  1. 1.Institute of Thermal Process Engineering, Thin Film Technology, Karlsruhe Institute of Technology (KIT)KarlsruheGermany

Personalised recommendations