ABSTRACT
The objective of this study was to experimentally investigate the effects of working fluids and internal diameters on the thermal resistance of rotating closed-loop pul¬sating heat pipes (RCLPHP). The RCLPHP were made of a copper tube with internal diameters of 1.50 mm and 1.78 mm, bent into the shape of a flower petal, and arranged into a circle with 11 turns. The evaporator section was located at the outer end of the tube bundle. R123, ethanol, and water were filled as the working fluids. The RCLPHP was rotated at centrifugal accelerations 0.5, 1, 3, 5, 10, and 20 times of the gravitational acceleration considered at the connection between the evaporator and the condenser sections. The heat input was varied from 30 W to 50 W, and then to 100 W, 150 W, and 200 W. It can be concluded that when the latent heat of evaporation increases, the pressure difference between the evaporator and the condenser sections decreases, and the thermal resistance increases. Moreover, when the internal diameter increases, the driving force increases and the frictional force proportionally decreases, or the Karman number increases, and the thermal resistance decreases.
KEYWORDS
PAPER SUBMITTED: 2016-08-27
PAPER REVISED: 2017-01-22
PAPER ACCEPTED: 2017-01-22
PUBLISHED ONLINE: 2017-02-12
THERMAL SCIENCE YEAR
2017, VOLUME
21, ISSUE
Issue 6, PAGES [2993 - 3000]
- Akachi, H. et al., Pulsating Heat Pipes, Proceedings, 5th Intl. Heat Pipe Symp., Melbourne, Australia, 1996, pp. 208-217.
- Maezawa, S. et al., Thermal Performance of Capillary Tube Thermosyphon, Proceedings, 9th Intl. Heat Pipe Conf., Albuquerque, USA, 1995, pp. 791-795.
- Soponpongpipat, N. et al., Investigation of the Startup Condition of a Closed Loop Oscillating Heat Pipe, Heat Transfer Eng., 30 (2009), 8, pp. 626-642.
- Payakaruk, T. et al., Correlations to Predict Heat Transfer Characteristics of an Inclined Closed Two-Phase Thermosyphon at Normal Operating Conditions, Appl. Therm. Eng., 20 (2000), 9, pp. 781-790.
- Jiang, L. et al., Fabrication and Thermal Performance of Grooved-Sintered Wick Heat Pipe, J. Cent. South Univ., 21 (2014), 2, pp. 668-676.
- Kammuang-lue, N. et al., Effect of Working Fluids on Thermal Effectiveness of Closed-Loop Pulsating Heat Pipe Applied in Ice Storage System, Proceedings, 8th Intl. Heat Pipe Symp., Kumamoto, Japan, 2006, pp. 323-328.
- Yeunyongkul, P. et al., Experimental Investigation of the Closed Loop Oscillating Heat Pipe Condenser for Vapor Compression Refrigeration, J. Appl. Sci. Eng., 15 (2012), 2, pp. 117-122.
- Kammuang-lue, N., Paksilp, W., Application of Closed-Loop Pulsating Heat Pipe as Engine Radiator, RMUTI J., 8 (2015), Special Issue 1, pp. 315-323.
- Aboutalebi, M. et al., Experimental Investigation on Performance of a Rotating Closed Loop Pulsating Heat Pipe, Int. Commun. Heat Mass., 45 (2013), pp. 137-145.
- Mohammadi, M. et al., Experimental Investigation of a Pulsating Heat Pipe Using Ferrofluid (Magnetic Nanofluid), ASME J. of Heat Transfer, 137 (2011), 1, pp. 1-3.
- Mangini, D. et al., A Pulsating Heat Pipe for Space Applications: Ground and Microgravity Experiments, Int. J. Therm. Sci., 95 (2015), pp. 53-63.
- Khandekar, S. et al., Closed Loop Pulsating Heat Pipes - Part B: Visualization and Semi- Empirical Modeling, Appl. Therm. Eng., 23 (2003), 16, pp. 2021-2033.
- Charoensawan, P. et al., Closed Loop Pulsating Heat Pipes - Part A: Parametric Experimental Investigations, Appl. Therm. Eng., 23 (2003), 16, pp. 2009-2020.
- Charoensawan, P., Terdtoon, P., Thermal Performance of Horizontal Closed-Loop Oscillating Heat Pipe, Appl. Therm. Eng., 28 (2008), 5-6, pp. 460-466.
- On-ai, K. et al., Effect of Working Fluid Types on Thermal Performance of Vertical Closed- Loop Pulsating Heat Pipe, Proceedings, 5th Intl. Conf. on Science, Technology and Innovation for Sustainable Well-Being, Luang Prabang, Lao PDR, 2013, pp. MME04 1-7.
- Sriwiset, C. et al., Evaluation of Optimum Turn Number for Closed-Loop Pulsating Heat Pipe at Normal Operation, Proceedings, 5th Intl. Conf. on Science, Technology and Innovation for Sustainable Well-Being, Luang Prabang, Lao PDR, 2013, pp. MME06 1-5.
- Kammuang-lue, N. et al., Effect of Working Fluids and Internal Diameters on Thermal Performance of Vertical and Horizontal Closed-Loop Pulsating Heat Pipes with Multiple Heat Sources, Therm. Sci., 20 (2016), 1, pp. 77-87.