The effect of wall microstructuring type on heat transfer while boiling in the flowing-down films of low-viscosity liquid


Аuthors

Volodin O. A.1*, Pecherkin N. I.1, Pavlenko A. N.1, Stepanov K. A.1, Zubkov N. N.2

1. Kutateladze Institute of Thermophysics, Siberian Branch of RAS, Novosibirsk, 630090, Russia
2. Bauman Moscow State Technical University, MSTU, 5, bldg. 1, 2-nd Baumanskaya str., Moscow, 105005, Russia

*e-mail: volodin_o@mail.ru

Abstract

Being an effective mean of interfacial heat transfer, the flowing-down thin liquid films are widely used in various industrial processes, such as absorption, rectification, evaporation, cooling, etc. To intensify heat transfer in various technical applications, various types of complex structured surfaces are used. The problem of their geometry impact on heat transfer remains an important issue of heat power engineering due to the processing technologies development.

The paper presents experimental data on the surface microstructure geometric characteristics impact on the heat transfer enhancement while boiling in flowing-down liquid films. The authors studied two types of microstructures: micro-fins with semi-closed subsurface pores and micro-pin structures. A binary mixture of R114/R21 refrigerants, which is a low-viscosity and well-wetting fluid, was used as a working fluid. The liquid film flow was realized over the outward surface of vertical cylinders in the laminar-wave mode. The heat flux density varied from zero to critical values.

To create microstructured surfaces, the authors employed the method of deforming cutting (patent of the Russian Federation, Zubkov N.N.).This is a method of mechanical processing, based on the undercutting of the surface layer of the workpiece material and subsequent deformation of the trimmed layer with macro- and microrelief formation in the form of ribs, pins, cells, and screwed profiles. The method of deformational cutting is non-waste. This method does not require the cutting coolants application. It is being implemented with standard metal-cutting equipment and allows processing of various materials with possibility of the surface area increasing up to 12 times.

The authors obtained new experimental data on heat transfer coefficients in evaporation and boiling regimes for microstructured surfaces with semi-closed pores, and for surfaces with micro-pin structures. It was demonstrated that the presence of semi-closed subsurface micropores, creating active nucleation sites, could significantly intensify the nucleate boiling process.

The studied micro pin-type surfaces without semi-closed micropores in the boiling regime practically do not offer advantages compared to a smooth surface. However, the heat transfer coefficients in the evaporation regime for such surfaces can be up to two times higher than the heat transfer coefficient for a smooth one.

It was shown that the heat transfer coefficients in the boiling regime for surfaces with semi-closed micropores are three times or more higher than the heat transfer coefficients for a smooth surface. The results were compared with the heat transfer characteristics of Gewa-T19D and Gewa-K19 industrial surfaces. It demonstrates the effectiveness of heat transfer surfaces with semi-closed subsurface pores developed by the authors, obtained by high-performance and economical deformational cutting method.

Keywords:

falling films, heat transfer intensification, nucleate boiling, refrigerants, deformational cutting method

References

  1. Attinger D., Frankiewicz C., Betz A.R., Schutzius T.M., Ganguly R., Das A., Kim C.-J., Megaridis C.M. Surface engineering for phase change heat transfer: A review. MRS Energy & Sustainability: A Review Journal, 2014, vol. 1, E4. DOI:10.1557/mre.2014.9

  2. Kim D.E., Yu D.I., Jerng D.W., Kim M.H., Ahn H.S. Review of boiling heat transfer enhancement on micro/nanostructured surfaces. Experimental Thermal and Fluid Science, 2015, vol. 66, pp. 173–196. DOI: 10.1016/j.expthermflusci.2015.03.023

  3. Pecherkin N.I., Pavlenko A.N., Volodin О.A. Heat transfer and crisis phenomena at the film flows of freon mixture over vertical structured surfaces. Heat Transfer Engineering, 2016, vol. 37, no. 3–4, pp. 257–268. DOI: 10.1080/01457632.2015.1052657

  4. Shchelchkov A.V., Popov I.A., Zubkov N.N. Boiling of a liquid on microstructured surfaces under free-convection conditions. Journal of Engineering Physics and Thermophysics, 2016, vol. 89, no. 5, pp. 1152–1160. DOI: 10.1007/s10891-016-1478-5

  5. Thors P., Zoubkov N. Method for making enhanced heat transfer surfaces. Patent US, no. 8573022 B2, Int. Cl. B21D53/01, 2013.

  6. Surtaev A.S., Pavlenko A.N., Kalita V.I., Kuznetsov D.V., Komlev D.I., Radyuk A.A., Ivannikov A.Yu. The influence of three-dimensional capillary-porous coatings on heat transfer at liquid boiling. Technical Physics Letters, 2016, vol. 42, no. 4, pp. 391–394. DOI: 10.1134/S106378501604026X

  7. Surtaev A.S., Pavlenko A.N., Kuznetsov D.V., Kalita V.I., Komlev D.I., Ivannikov A.Yu., Radyuk A.A. Heat transfer and crisis phenomena at pool boiling of liquid nitrogen on the surfaces with capillary-porous coatings. Intern. Journal of Heat and Mass Transfer, 2017, vol. 108, pp. 146–155. DOI: 10.1016/j.ijheatmasstransfer.2016.11.100

  8. Starodubtseva I.P., Pavlenko A.N. Quenching by falling cryogenic liquid film of extremely overheated plate with structured capillary-porous coating. Journal of Engineering Thermophysic, 2018, vol. 27, no. 3, pp. 294–302. DOI: 10.1134/S1810232818030049

  9. Gogonin I.I. Heat transfer in boiling of liquid in a film moving under gravity. Journal of Engineering Physics and Thermophysics, 2010, vol. 83, no. 4, pp. 876-881. doi:10.1007/s10891-010-0409-0

  10. Volodin O.A., Pecherkin N.I., Pavlenko A.N., Zubkov N.I. Heat transfer and crisis phenomena at boiling of refrigerant films falling down the surfaces obtained by deformational cutting. Interfacial Phenomena and Heat Transfer, 2017, vol. 5, pp. 215–222.  DOI:10.1615/InterfacPhenomHeatTransfer.2018025507

  11. Pecherkin N.I., Pavlenko A.N., Volodin O.A. Heat transfer and critical heat flux at evaporation and boiling in refrigerant mixture films falling down the tube with structured surfaces. Int. J. Heat and Mass Transfer, 2015, vol. 90, no. 11, pp. 149–158. DOI:10.1016/j.ijheatmasstransfer.2015.06.050

  12. Pavlenko A.N., Pecherkin N.I., Volodin O.A. Teploobmen i krizisnye yavleniya v stekayushhikh plenkakh zhidkosti pri isparenii i kipenii [Heat transfer and crisis phenomena in the falling liquid films at evaporation and boiling]. Novosibirsk: SB RAS Press, 2016. 196 p. In Russ.

  13. Ayub Z.H. Pool boiling from GEWA surfaces in water and R-113 (1986). Retrospective Theses and Dissertations. Paper 7979. DOI:10.1007/BF01004023

mai.ru — informational site of MAI

Copyright © 2009-2024 by MAI