International Scientific Journal

Thermal Science - Online First

online first only

Experimental investigation of heat pipe thermal performance with microgrooves fabricated by wire electrical discharge machining (wire-EDM)

This work presents the use of electrical discharge machining (EDM) technology for manufacturing of three different types of axial microgrooves in heat pipes. This specific process, called wire electrical discharge machining (or wire-EDM), allows the fabrication of microgrooves on the inner wall of a heat pipe with accuracy. Different from other capillary structures, such as composite wick and screen mesh, the material is removed from the pipe's container in order to conceive the capillary structure, which contributes with the mass reduction of the passive two-phase heat transfer device. The heat pipes were manufactured from a straight copper pipe with the external diameter of 9.45 mm, the inner diameter of 6.20 mm and a total length of 200 mm. Three types of axial microgrooves were manufactured for constant width (35 μm) and varying the depth (from 30 up to 48 μm) and thickness (from 35 up to 70 μm). The number of microgrooves was also varied from 21 up to 32 microgrooves. Water was used as the working fluid and the loading filling ratio was 60% of the evaporator volume. The condenser was cooled by air forced convection, the adiabatic section was insulated and the evaporator was heated by an electrical resistor and it was insulated from the environment with aeronautic thermal insulation. The thermal performance of the heat pipes are analyzed based on experimental results, so the heat pipes were tested at the horizontal and different inclinations under different low heat loads (from 5 up to 50 W or a heat flux from 0.21 up to 2.10 W/cm2). The experimental results showed that the axial microgrooves manufactured by the wire-EDM process worked satisfactorily in all analyzed cases and microgrooves of Type #1 showed a better thermal performance when compared with the others.
PAPER REVISED: 2018-07-01
PAPER ACCEPTED: 2018-07-05
  1. Krambeck, L., Nishida, F. B., Aguiar, V. M., Santos, P. H. D., Antonini Alves, T., Thermal Performance Evaluation of Different Passive Devices for Electronics Cooling, Thermal Science, OnLine-First Issue00 (2017), pp 300
  2. Faghri, A., Heat Pipes: Review, Opportunities and Challenges, Frontiers in Heat Pipes, 5 (2014), pp 01-48
  3. Reay, D. A., Kew, P. A., McGlen, R. J., Heat Pipe: Theory, Design and Applications, Butterworth-Heinemann, Amsterdam, NED, 2014
  4. Peterson, G. P., An Introduction to Heat Pipes: Modeling, Testing and Applications, (Thermal Management of Microelectronic and Electronic System Series), Wiley-Interscience, New York, USA, 1994
  5. Groll, M., Rösler, S., Operation Principles and Performance of Heat Pipes and Closed Two-Phase Thermosyphons, Journal of Non-Equilibrium Thermodynamics, 17 (1992), pp. 091-151
  6. Chi, S.W., Heat Pipe Theory and Practice: A Sourcebook, Hemisphere Publishing Corporation, Washington, USA, 1976
  7. Krambeck, L., Bartmeyer, G. A., Fusão, D., Santos, P. H. D., Antonini Alves, T., Experimental Research of Capillary Structure Technologies for Heat Pipes, Proceedings of the 24th ABCM International Congress of Mechanical Engineering, Curitiba, Brazil, 2017, COBEM-2017-1170
  8. Krambeck, L., Nishida, F. B., Santos, P. H. D., Antonini Alves, T., Heat Pipe with Axial Microgrooves Fabricated by Wire Electrical Discharge Machining (Wire-EDM), Proceedings of the 9th World Conference on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics, Foz do Iguaçu, Brazil, 2017
  9. Tang, Y., Chi, Y., Chen, J. C., Deng, X. X., Liu, L., Liu, X. K., Wan, Z. P., Experimental Study of Oil-Filled High-Speed Spin Forming Micro-Groove Fin-Inside Tubes, International Journal of Machine Tools & Manufacture, 47 (2006), pp. 1059-1068
  10. Wang, X., Tang, Y., Chen, P., Investigation into Performance of a Heat Pipe with Micro Grooves Fabricated by Extrusion-Ploughing Process, Energy Conversion and Management, 50 (2009), pp. 1384-1388
  11. Chen, S. W., Hsieh, J. C., Chou, C. T., Lin, H. H., Shen, S. C., Tsai, M. J., Experimental Investigation and Visualization on Capillary and Boiling Limits of Micro-Grooves Made by Different Processes, Sensors and Actuators A, 139 (2007), pp. 78-87
  12. Yang, X., Yan, Y. Y., Mullen, D., Recent Developments of Lightweight, High Performance Heat Pipes, Applied Thermal Engineering, 33-34 (2012), pp. 1-14
  13. Nishida, F. B., Development of Heat Pipes with Microgrooves Fabricated by Wire Electrical Discharge Machining (in Portuguese), Dissertação de Mestrado em Engenharia Mecânica, Universidade Tecnológica Federal do Paraná, Ponta Grossa, BRA, 2016
  14. Li, Y., Xiao, H., Lian, B., Tang, Y., Zeng Z. X., Forming Method of Axial Micro Grooves Inside Copper Heat Pipe, Transactions of Nonferrous Metals Society of China, 18 (2008), pp. 1229-1233
  15. Chang, Y. W., Cheng, C. H., Wang, J. C., Chen, S. L., Heat Pipe for Cooling of Electronic Equipment, Energy Conversion and Management, 49 (2008), pp. 3398-3404
  16. Tang, Y., Chen, P., Wang, X. Experimental Investigation into the Performance of Heat Pipe with Micro Grooves Fabricated by Extrusion-Ploughing Process, Energy Conversion and Management, 51 (2010), pp. 1849-1854
  17. Tang, Y., Deng, D., Huang, G., Wan, Z., Lu, L., Effect of Fabrication Parameters on Capillary Performance of Composite Wicks for Two-Phase Heat Transfer Devices, Energy Conversion and Management, 66 (2013), pp. 66-76
  18. Sommer, C., Non-Traditional Machining Handbook, Advance Publishing Inc., Houston, USA, 2000
  19. Bobbili, R., Madhu, V., Gogia, A.K., Modelling and Analysis of Material Removal Rate and Surface Roughness in Wire-Cut EDM of Armour Materials, Engineering Science and Technology, 18 (2015), pp. 664-668
  20. ***, Vancouver Wire EDM, Machinists.htm
  21. Krambeck, L., Experimental Investigation of Wire Mesh Thermal Performance in Heat Pipes (in Portuguese), Trabalho de Conclusão de Curso de Graduação em Engenharia Mecânica, Universidade Tecnológica Federal do Paraná, Ponta Grossa, BRA, 2016
  22. Santos, P. H. D., Reis, L. S., Marquardt, L. S., Vicente, K. A. T., Antonini Alves, T., Modeling and Experimental Tests of a Copper Thermosyphon, Acta Scientiarum. Technology, 39 (2017), pp. 59-68
  23. American Society of Heating, Refrigerating and Air-Conditioning Engineers, ASHARE Handbook: Fundamentals, ASHARE, New York, USA, 2017
  24. Holman, J. P., Experimental Methods for Engineers, McGraw-Hill, New York, USA, 2011
  25. Ku, J., Operating Characteristics of Loop Heat Pipes, Proceedings of the 29th International Conference on Enviromental System, Denver, USA, 1999
  26. Hu, Y., Cheng, J., Zhang, W., Shirakashi, R., Wang, S., Thermal Performance Enhancement of Grooved Heat pipes with Inner Surface Treatment, International Journal of Heat and Mass Transfer, 67 (2013), pp. 416-419