Abstract
The Closed Loop Pulsating Heat Pipe (CLPHP) is a very promising passive two-phase heat transfer device for relatively high heat fluxes (up to 30 W/cm2) patented by Akachi (1990, 1993). Although the CLPHP has a simple structure, its working principles are very complex compared to the standard heat pipe with a porous wick. One of the most debated issues deals on how the thermal performance is affected by the inclination and by the action of different gravity fields (terrestrial, lunar, martian and microgravity). Even if the internal tube diameter satisfies the conventional slug flow regime requirement on the Bond number, gravity force still plays an important role on the PHP behaviour. Heat input and the number of turns are two of the most important indirect parameters linked to the gravity issue. A complete numerical campaign has been performed by means of a FORTRAN code at different inclination angles and gravity levels on various PHP. The numerical model is able to estimate both the hydrodynamic and the thermal performance of a CLPHP with different working fluids. The analysis shows that the effect of local pressure losses due to bends is important and must be taken into account, in particular in the horizontal operation which is the reference point for space applications. Numerical results are matched with the experimental data quoted in literature and both good qualitative and quantitative agreement have been found.
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References
Akachi, H.: Structure of a heat pipe. U.S. Patent 4,921,041 (1990)
Akachi, H.: Structure of a micro heat pipe. US Patent 5,490,558 (1993)
Carey, V.P.: Liquid–Vapor Phase-Change Phenomena. Taylor & Francis (2007)
Charoensawan, P., Terdtoon, P.: Thermal performance of horizontal closed-loop pulsating heat pipes. Appl. Therm. Eng. 28, 460–466 (2008)
Darby, R.: Correlate pressure drops through fittings. Chem. Eng. 106(7), 101–104 (1999)
Darby, R.: Correlate pressure drops through fittings. Chem. Eng. 108(4), 127–130 (2001)
Gu, J., Kawaji, M., Futamata, R.: Effects of gravity on the performance of pulsating heat pipes. J. Thermophys. Heat Transf. 18(3), 370–378 (2004)
Gu, J., Kawaji, M., Futamata, R.: Microgravity performance of micro pulsating heat pipe. Microgravity Sci. Technol. 16, 181–185 (2005)
Han, Y., Shikazono, N.: Measurement of the liquid film thickness in micro tube slug flow. Int. J. Heat Fluid Flow 30, 842–853 (2009)
Holley, B., Faghri, A.: Analysis of pulsating heat pipe with capillary wick and varying channel diameter. Int. J. Heat Mass Transfer 48, 2635–2651 (2005)
Incropera, F.P., DeWitt, D.P.: Fundamentals of Heat and Mass Transfer, 6th edn. Wiley (2007)
Khandekar, S.: Pulsating heat pipe based heat exchangers. In: Proc. Of the 21st Int. Symposium on Transport Phenomena, Kaohsiung City, Taiwan, 2–5 November (2010)
Khandekar, S., Groll, M.: An insight into thermo-hydrodynamic coupling in closed loop pulsating heat pipes. Int. J. Therm. Sci. 43, 13–20 (2004)
Khandekar, S., Groll, M.: Roadmap to realistic modeling of closed loop pulsating heat pipes. In: Proc. of the 9th International Heat Pipe Symposium, Kuala Lumpur, Malaysia (2008)
Khandekar, S., Gautam, A.P., Sharma, P.K.: Multiple quasi-steady states in a closed loop pulsating heat pipe. Int. J. Therm. Sci. 48, 536–546 (2009)
Kim, J.S., Bui, N.H., Jung, H.S., Lee, W.H.: The study on pressure oscillation and heat transfer characteristics of oscillating capillary tube heat pipe. KSME Int. J. 17(11), 1533–1542 (2003)
Mameli, M., Marengo, M., Zinna, S.: Thermal simulation of a pulsating heat pipe: effects of different liquid properties on a simple geometry. In: Proc. of the 7th Int. Conf. on Heat Transfer, Fluid Mechanics and Thermodynamics, Antalya, Turkey, 19–21 July (2010)
Miyazaki, Y.: Cooling of notebook pcs by flexible oscillating heat pipes. In: Proc. of ASME INTERPACK, San Francisco, California, USA, 17–22 July (2005)
Rittidech, S., Wannapakne, S.: Experimental study of the performance of a solar collector by closed-end oscillating heat pipe. Appl. Therm. Eng. 27, 1978–1985 (2007)
Sakulchangsatjatai, P., Chareonsawan, P., Waowaew, T., Terdtoon, P., Murakami, M.: Mathematical modelling of closed-end pulsating heat pipes operating with a bottom heat mode. Heat Transf. Eng. 29(3), 239–254 (2008)
Shafii, M.B., Faghri, A., Zhang, Y.: Thermal modeling of unlooped and looped pulsating heat pipes. ASME J. Heat Trans. 123, 1159–1162 (2001)
Shah, R.K.: Thermal entry length solutions for the circular tube and parallel plates. In: Proc. 3rd National Heat Mass Transfer Conference, IIT Bombay, vol. I, Paper HMT-11–75 (1975)
Woo, J., Kim, J., Han, K., Ahn, S.: A study on cooling performance of heat sink using pulsating heat pipe. In: Proc. of the 9th Int. Heat Pipe Symposium, Kuala Lumpur, Malaysia, 17–20 November (2008)
Yang, H., Khandekar, S., Groll, M.: Operational limit of closed loop pulsating heat pipe. Appl. Therm. Eng. 28, 49–59 (2008)
Zhang, Y., Faghri, A.: Oscillatory flow in pulsating heat pipes with arbitrary numbers of turns. J. Thermophys. Heat Transf. 17(3), 340–347 (2003)
Zuo, Z.J., North, M.T., Ray, L.: High heat flux heat pipe mechanism for cooling of electronics. IEEE Trans. Compon. Packag. Technol. 24(2), 220–225 (2001a)
Zuo, Z.J., North, M.T., Ray, L.: Combined Pulsating and Capillary Heat Pipe Mechanism for Cooling of High Heat Flux Electronic. Internal Report, Thermacore Inc. (2001b)
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Mameli, M., Marengo, M. & Zinna, S. Numerical Investigation of the Effects of Orientation and Gravity in a Closed Loop Pulsating Heat Pipe. Microgravity Sci. Technol. 24, 79–92 (2012). https://doi.org/10.1007/s12217-011-9293-2
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DOI: https://doi.org/10.1007/s12217-011-9293-2