Cover
Vol. 26 No. 1 (2026)

Published: July 28, 2026

Pages: 26-34

Research Article

Experimental Study of Boiling Heat Transfer in Zigzag and Symmetric Circular-Cavities Microchannels

Yamam Taqi Abed 1 Ahmed Jasim Shkarah 1
1 Department of Mechanical Engineering, College of Engineering, University of Thi-Qar, Nasiriyah, Iraq
History
  • Received: April 20, 2026
  • Revised: May 20, 2026
  • Accepted: June 16, 2026
  • Available Online: July 28, 2026
DOI

https://doi.org/10.33971/bjes.26.1.4

Abstract

An experiment was conducted on two types of microchannels (zigzag and symmetrical circular) using water as the working fluid under normal boiling conditions. Heat fluxes ranging from 180 to 780 kW/m² were used, the Reynolds number varied from 58 to 107, and the water flow was streamlined. Temperatures were measured at ten ports (inlet, outlet, and walls). The results showed that for the zigzag channel at a heat flux of 580 kW/m², the average wall temperature decreased from 112°C to 87°C as the Reynolds number increased to 107. Both the Nusselt number (from 42 to 86) and the Reynolds number (from 58 to 107) also increased. The zigzag channel exhibited an improvement in heat transfer coefficient with a 30% decrease in the average temperature. The temperature of the circular cavity channel decreased from 126°C to 96°C, while the flow remained constant. Flow patterns were captured using a high-resolution camera for study during boiling.

Keywords

References

  1. A. Serizawa, “Fluid flow and heat transfer in microchannels”, JSME Report, Research Committee on Heat Transfer and Fluid Flow in Microchannels, P-SC295, 2001.
  2. S. M. Ghiaasiaan and S. I. Abdel-Khalik, “Two-phase flow in microchannels”, Advances in Heat Transfer, Vol. 34, pp. 145-254, 2001. https://doi.org/10.1016/S0065-2717(01)80012-5
  3. A. Serizawa and Z. Feng, “Review of two-phase flow in microchannels”, in Proc. of the US–Japan Seminar on Two-Phase Flow Dynamics, Santa Barbara, CA, 2000.
  4. G. Maharudrayya, S. Jayanti, and A. P. Deshpande, “Pressure drop and heat transfer in zigzag channels”, Experimental Thermal and Fluid Science, Vol. 32, Issue 1, pp. 283-291, 2007. https://doi.org/10.1016/j.expthermflusci.2007.03.004
  5. B. Huang, H. Li, and T. Xu, “Experimental investigation of the flow and heat transfer characteristics in microchannel heat exchangers with reentrant cavities”, Micromachines, Vol. 11, Issue 4, p. 403, 2020. https://doi.org/10.3390/mi11040403
  6. Y. Tu and Y. Zeng, “Numerical study on flow and heat transfer characteristics of supercritical CO₂ in zigzag microchannels”, Energies, Vol. 15, Issue 6, p. 2099, 2022. https://doi.org/10.3390/en15062099
  7. T. Hou and D. Xu, “Flow and Heat Performance of Microchannel Heat Sinks with Concave Cavities to WaterCool Leds”, SSRN Electronic Journal, 2023. https://doi.org/10.2139/ssrn.4617565
  8. Y. Lee, S. Lee, H. B. Park, K. W. Seo, and D. Lee, “Thermal-hydraulic performance analysis of zigzag channel PCHE according to bending angle”, in Proc. of the Korean Nuclear Society Spring Meeting, Jeju, Korea, May 9-10, 2024.
  9. M. Staszak and G. Musielak, “Numerical simulations of flow and heat exchange in zigzag-shaped microchannels”, Applied Sciences, Vol. 14, Issue 21, p. 9826, 2024. https://doi.org/10.3390/app14219826
  10. B. Mathew, F. Alnaimat, A. G. Hussain, S. Atatreh, B. M. S. Kakah, and Y. A. Ali, “Nusselt number and friction factor in zig-zag microchannels subjected to constant heat flux”, International Journal of Thermofluids, Vol. 26, p. 101079, 2025. https://doi.org/10.1016/j.ijft.2025.101079
  11. F. Li, Z. Tan, H. He, Y. Zhou, X. Tang, and W. Zhu, “Research on thermal performance of the microchannel with internal cavities under Al₂O₃-water nanofluid”, Energies, Vol. 18, Issue 16, p. 4419, 2025. https://doi.org/10.3390/en18164419
  12. F. P. Incropera, D. P. DeWitt, T. L. Bergman, and A. S. Lavine, Fundamentals of Heat and Mass Transfer, 8th ed., New York: Wiley, 2017.
  13. J. P. Holman, Heat Transfer, 10th ed., New York: McGraw-Hill, 2010.
  14. W. M. Kays and M. E. Crawford, Convective Heat and Mass Transfer, 3rd ed., New York: McGraw-Hill, 1993.
  15. B. R. Munson, D. F. Young, T. H. Okiishi, and W. W. Huebsch, Fundamentals of Fluid Mechanics, 7th ed., New York: Wiley, 2013.
  16. A. Bejan, Convection Heat Transfer, 4th ed., New York: Wiley, 2013.