Correlation to Predict Thermal Performance According to Working Fluids of Vertical Closed-Loop Pulsating Heat Pipe
The objectives of this paper are to investigate effects of dimensionless numbers on thermal performance of the vertical closed-loop pulsating heat pipe (VCLPHP) and to establish a correlation to predict the thermal performance of the VCLPHP. The CLPHPs were made of long copper capillary tubes with inner diameters of 1.50, 1.78, and 2.16mm and bent into 26 turns. Then, both ends were connected together to form a loop. The evaporator, adiabatic, and condenser sections length were equal to 50 and 150 mm. R123, R141b, acetone, ethanol, and water were chosen as variable working fluids with constant filling ratio of 50% by total volume. Inlet temperature of heating medium and adiabatic section temperature was constantly controlled at 80 and 50oC, respectively. Thermal performance was represented in a term of Kutateladze number (Ku). It can be concluded that when Prandtl number of liquid working fluid (Prl), and Karman number (Ka) increases, thermal performance increases. On contrary, when Bond number (Bo), Jacob number (Ja), and Aspect ratio (Le/Di) increases, thermal performance decreases. Moreover, the correlation to predict more precise thermal performance has been successfully established by analyzing on all dimensionless numbers that have effect on the thermal performance of the VCLPHP.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1092609Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1877
 H. Akachi, F. Polasek, and P. Stulc, "Pulsating heat pipes,” in Proc. 5th Intl. Heat Pipe Symp., Melbourne, Australia, 1996, pp. 208–217.
 S. Maezawa, K. Y. Gi, A. Minamisawa, and H. Akachi, "Thermal performance of capillary tube thermosyphon,” in Proc. 9th Intl. Heat Pipe Conf., Albuquerque, USA, 1995, pp. 791–795.
 J. L. Xu, Y. X. Li, and T. N. Wong, "High speed flow visualization of a closed loop pulsating heat pipe,” Heat Mass Transfer, vol. 48, pp. 3338–3351, 2005.
 N. Soponpongpipat, P. Sakulchangsatjatai, N. Kammuang-lue, and P. Terdtoon, "Investigation of the startup condition of a closed loop oscillating heat pipe,” Heat Transfer Eng., vol. 30, no. 8, pp. 626–642, 2009.
 P. Charoensawan, S. Khandekar, M. Groll, and P. Terdtoon, "Closed loop pulsating heat pipes - part a: parametric experimental investigations,” Appl. Therm. Eng., vol. 23, no. 16, pp. 2009–2020, 2003.
 S. Khandekar, P. Charoensawan, M. Groll, and P. Terdtoon, "Closed loop pulsating heat pipes - part b: visualization and semi-empirical modeling,” Appl. Therm. Eng., vol. 23, no. 16, pp. 2021–2033, 2003.
 X. M. Zhang, "Experimental study of a pulsating heat pipe using FC-72, ethanol, and water as working fluids,” Exp. Heat Transfer, vol. 17, no. 1, pp. 47–67, 2004.
 P. Sakulchangsatjatai, P. Terdtoon, T. Wongratanaphisan, P. Kamonpet, and M. Murakami, "Operation modeling of closed-end and closed-loop oscillating heat pipes at normal operating condition,” Appl. Therm. Eng., vol. 24, no. 7, pp. 995–1008, 2004.
 N. Kammuang-lue, P. Sakulchangsatjatai, M. Sornsueb, and P. Terdtoon, "Effect of working fluids on thermal effectiveness of closed-loop pulsating heat pipe applied in ice storage system.” in Proc. 8th Intl. Heat Pipe Symp.,” Kumamoto, Japan, 2006, pp. 323–328.
 N. Kammuang-lue, P. Sakulchangsatjatai, and P. Terdtoon, "Effect of working fluids on thermal characteristic of a closed-loop pulsating heat pipe heat exchanger: a case of three heat dissipating devices,” in Proc. IEEE 14th Electronics Packaging Technology Conf., Singapore, 2012, pp. 142–147.
 P. Charoensawan, P. Terdtoon, P. Tantakom, and P. Ingsuwan, "Effect of evaporator section lengths, number of turns and working fluid on internal flow patterns of a vertical closed-loop oscillating heat pipe” in Proc. 7th Intl. Heat Pipe Symp., Jeju, Korea., 2003, pp. 360–367.
 P. Charoensawan, P. Terdtoon, P. Tantakom, and P. Ingsuwan, and M. Groll, "Effect of inclination angles, filling ratios and total lengths on heat transfer characteristics of a closed-loop oscillating heat pipe,” in Proc. 6th Intl. Heat Pipe Symp., Chiang Mai, Thailand, 2000, pp. 421–430.
 Y. Zhang and A. Faghri, "Heat transfer in a pulsating heat pipe with open end,” Heat Mass Transfer, vol. 45, pp. 755–764, 2002.
 M. Groll, and S. Khandekar, "Pulsating heat pipes: progress and prospects,” in Proc. Intl. Conf. on Energy and the Environment, vol. 1, Shanghai, China, 2003, pp. 723–730.
 M. B. Shafii, A. Faghri, and Y. Zhang, "Thermal modeling of unlooped and looped pulsating heat pipes,” ASME J. Heat Transfer, vol. 123, pp. 1159–1171, 2001.
 M. B. Shafii, A. Faghri, and Y. Zhang, "Analysis of heat transfer in unlooped and looped pulsating heat pipes,” Intl. J. Numerical Methods for Heat and Fluid Flow, vol. 12, no. 5, pp. 585–609, 2002.
 C. Sriwiset, N. Kammuang-lue, P. Sakulchangsatjatai, and P. Terdtoon, "Evaluation of optimum turn number for closed-loop pulsating heat pipe at normal operation,” in Proc. 5th Intl. Conf. on Science, Technology and Innovation for Sustainable Well-Being, Luang Prabang, Lao PDR, 2013, pp. MME06 1–5.