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Experimental investigation of gravity-assisted wickless heat pipes (thermosyphons) at low heat inputs for solar application

Treść / Zawartość
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Warianty tytułu
Języki publikacji
EN
Abstrakty
EN
The performance of ten wickless heat pipes without adiabatic sections is investigated experimentally at low heat inputs 120 to 2000 W/m2 for use in solar water heaters. Three heat pipe diameter groups were tested, namely 16, 22, and 28.5 mm. Each group had evaporator lengths of 1150, 1300, and 1550 mm, respectively, with an extra evaporator length of 1800 mm added to the second group. The condenser section length of all heat pipes was 200 mm. Ethanol, methanol, and acetone were utilized as working fluids, at inventory of 25%, 50%, 70%, and 90% by evaporator volume respectively. The 22 mm diameter pipes were tested at inclination angles 30°, 45°, and 60°. Other diameter groups were tested at 45° only. Experiments revealed increased surface temperatures and heat transfer coefficients with increased pipe diameter and evaporator length, and that increased working fluid inventory caused pronounced reduction in evaporator surface temperature accompanied by improved heat transfer coefficient to reach maximum values at 50% inventory for the selected fluids. Violent noisy shocks were observed with 70% and 90% inventories with the tested heat pipes and the selected working fluids with heat flux inputs from 320–1900 W/m2. These shocks significantly affected the heat pipes heat transfer capability and operation stability. Experiments revealed a 45° and 50% optimum inclination angle of fill charge ratio respectively, and that wickless heat pipes can be satisfactorily used in solar applications. The effect of evaporator length and heat pipe diameter on the performance was included in data correlations.
Rocznik
Strony
257--276
Opis fizyczny
Bibliogr. 25 poz., rys., tab., wykr., wz.
Twórcy
  • Renewable Energy Directorate, Ministry of Science and Technology, Karrada, Al-Jaderiyah, Baghdad, Iraq
Bibliografia
  • [1] Jiao B., Qiu L., Zhang X., Zhang Y.: Investigation of the effect of filling ratio on the steady-state heat transfer performance of a vertical two-phase closed thermosyphon. Appl. Therm. Eng. 28(2008), 11, 1417–1426.
  • [2] Larkin B.S.: An experimental investigation of a low heat flux, wickless heat pipe. Trans. Canadian Soc. Mech. Eng. 7(1983), 2, 96–99.
  • [3] Dristoiu D., Ristoiu T., Cosma C., Cenan D.: Experimental investigation of inclination angle on heat transfer characteristics of closed two-phase thermosyphon. In. Proc. 5th General Conf. Balkan Physical Union, Aug., 2003.
  • [4] Shiraishi M. Nakano A. Terdtoon P. , Murakami M.: Performance limits of inclined gravity assisted heat pipe. In: Proc. 10th Int. Heat Pipe Conf., H2-9, Sep. 21–25, 1997.
  • [5] Shiraishi M., Kim Y., Murakami M., Terdtoon P.: A correlation for the heat transfer rate in an inclined two- phase closed thermosyphon. In: Proc. 5th Int. Heat Pipe Symp., Melbourne, 1996.
  • [6] Negishi N., Sawada T.: Heat transfer performance of inclined two- phase closed thermosyphon. Int. J. Heat Mass Transf. 26(1983), 8, 1207–1213.
  • [7] Mahdy M.: Experimental Investigation of Low Heat Flux Heat Pipes with and without Adiabatic Section for Solar Application. PhD thesis, University of Baghdad, Baghdad 2005.
  • [8] Kayansayn N.: The gravity assisted heat pipe with application to concrete shell steam condensers. J. Heat Recov. Sys. CHP 6(1986), 5, 389–397.
  • [9] Hussein H., El-Ghetany H., Nada S.: Performance of wickless heat pipe flat plate solar collectors having different pipe cross section geometries and filling ratios. Energy Convers. Manage. 47(2006), 11-12, 1539–1549.
  • [10] El-Nasr M., El-Haggar S.: Performance of a wickless heat pipe solar collector. J. Energy Sourc. 15(1993), 3, 513–522.
  • [11] Hussein H.: Theoretical and Experimental Investigation of a Wickless Heat Pipe Flat Plate Solar Collector. PhD thesis, Faculty of Engineering, Cairo University, Cairo 1997.
  • [12] Murgu Z., Murgu D., Cojocaru L., Huzum M., Tvardochlieb E.: Heat pipes for sun energy conversion. In: Proc. 3rd Int. Heat Pipe Conf., Palo Alto, 1978.
  • [13] Witwit A.M.: A Study of The Gravity Assisted and Variable Conductance Heat Pipes With an Internal Wall Separating Liquid and Vapor Phases. PhD thesis. Mech. Eng. Dept., University of Baghdad, Baghdad 1998.
  • [14] Hahne E., Gross U.: The Influence of The Inclination Angle on the Performance of a Closed Two Phase Thermosyphon. In: Advances in Heat Pipe Technology ( D. Reay, Ed.), 1982, 125–136.
  • [15] El-Genk M., Saber H.: Heat transfer correlations for small uniformly heated liquid pools. Int. J. Heat Mass Transf. 41(1998), 2, 261–274 .
  • [16] El-Genk M., Saber H.: Heat transfer in the evaporator of closed two phase thermosyphons. In: Proc. 10th Int. Heat Pipe Conf. X-10 Sep. 21–25, 1997.
  • [17] Imura H., Kusuda H., Ogata T., Miyazki T., Sakamoto N.: Heat transfer in two phase closed type thermosyphons. J. Heat Tran. Jap. Res. 8(1979), 2, 41–53.
  • [18] Imura H., Kusuda H., Ogata J., Miyazaki T., Sakamoto N.: Heat transfer in two-phase closed type thermosyphon. Trans. JSME B 45(1979), 393, 712–722.
  • [19] Kaminaga F., Hashimoto H., Feroz M., Goto K., Masumura K.: Heat transfer characteristics of evaporation and condensation in a two-phase closed thermosyphon. In: Proc. 10th Int. Heat Pipe Conf. H-1-6, Sep. 21–25, 1997.
  • [20] Noie S.H.: Heat transfer characteristics of a two-phase closed thermosyphon. Appl. Therm. Eng. 25(2005), 495–506.
  • [21] Jialun H., Ma Tongze M., Zhengfang Z.: Investigation of boiling liquid pool height of a two phase closed thermosyphon. In: Proc. 8th Int. Heat Pipe Conf., 1992, 154–159.
  • [22] Sayegh A. Danielewicz J., Tomczak W.: Thermal performance of low density heat transfer in two phase closed thermosyphon. In: proc. 10th Int. Heat Pipe Conf., H-2-8, Stuttgart, Sep. 21–25, 1997.
  • [23] Casarosa A., Latrofa E., Shelginski A.: The geyser effect in a two- phase thermosyphon. Int. J. Heat Mass Transf. 26(1983), 6, 933–941.
  • [24] Bezrodney M., Elekseyenko D.: Boiling heat transfer in closed two phase thermosyphon. Heat Transfer-Soviet Res. 9(1977), 5, 14–19.
  • [25] Imura H., Ipposhi S., Sakamoto M.: Experimental investigation of critical heat flux in two phase closed thermosyphon. In: Proc. 10th Int. Heat Pipe Conf., H-2-7, Stuttgart, Sep. 21–25, 1997.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-6867ba99-f6d2-4cf6-a075-808f3dbfd677
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