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Experimental and Calculated Investigation of a Natural Circulation Loop’s Thermal-Hydraulic Characteristics

  • HEAT AND MASS TRANSFER AND PROPERTIES OF WORKING FLUIDS AND MATERIALS
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Abstract—

The results from experimental investigation into hydrodynamics and heat transfer in a two-phase natural circulation loop (NCL) under atmospheric pressure are presented. The experiments were carried out for liquids having essentially different properties: water, ethanol, and perfluorohexane C6F14 (the product trademark is FC-72). The circulation velocity in the NCL is not known in advance but is a complex function of the specified parameters (heat flux and liquid temperature at the heated section inlet) and of the two-phase flow internal characteristics. The liquid temperatures at the heated section inlet, the wall temperature over the section height, and also the circulation velocity were measured in the experiments at a specified heat flux; in addition, the two-phase flow at the loop riser leg outlet was filmed on video. The experiments and analysis have shown that flow hydrodynamic instability (circulation velocity pulsations) is really unavoidable in a two-phase NCL. Hydrodynamic instability with a high circulation velocity amplitude and with the occurrence of backward flows is typical for regimes involving significant liquid subcooling values at the heated section inlet and for NCLs containing an extended part with single-phase convection. This instability, which is characteristic for experiments with water, is due to the displacement of the boiling incipience section over the section height; the instability also persists at small subcooling values but with a low pulsation amplitude. Under the developed saturated liquid nucleate boiling conditions (at high heat flux values), the circulation velocity and wall temperature pulsations have small amplitudes, and the flow can be regarded as stable. In the experiments with perfluorohexane, the smallest wall temperature and circulation velocity pulsations were pointed out, which is attributed to a relatively high value of reduced pressure. In the experiments with ethanol, instability occurs in the developed nucleate boiling region (q > 35 kW/m2); this instability is caused by periodically alternating two-phase flow structure (regime). A procedure for calculating a low-pressure NCL is developed, in which the two-phase flow’s local parameters (void fraction, phase velocities, and pressure) are calculated according to a modified homogeneous model (taking into account the phase distribution factor and phases slip) and a dispersed-annular flow model taking into account the droplet entrainment and deposition phenomena. A comparison of the NCL calculation results with the experimental data obtained for three different liquids has shown that they are in good agreement with each other.

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REFERENCES

  1. N. O. Zubov, O. N. Kaban’kov, V. V. Yagov, and L. A. Sukomel, “Prediction of friction pressure drop for low pressure two-phase flows on the basis of approximate analytical models,” Therm. Eng 64, 898–911 (2017). https://doi.org/10.1134/S0040601517120114

    Article  Google Scholar 

  2. G. B. Wallis, One-Dimensional Two-Phase Flow (McGraw-Hill, New York, 1969; Mir, Moscow, 1972).

  3. S. Kakaç and B. Bon, “A review of two-phase flow dynamic instabilities in tube boiling systems,” Int. J. Heat Mass Transfer. 51, 399–433 (2007).

    Article  MATH  Google Scholar 

  4. A. Nayak and P. Vijayan, “Flow instabilities in boiling two-phase natural circulation systems: A review,” Sci. Technol. Nucl. Install. 2008, 1–15 (2008). https://doi.org/10.1155/2008/573192

    Article  Google Scholar 

  5. S. Bhattacharyya, D. Basu, and P. Das, “Two-phase natural circulation loops: A review of the recent advances,” Heat Transfer Eng. 33, 461–482 (2012).

    Article  Google Scholar 

  6. J. A. Boure, A. E. Bergles, and L. S. Tong, “Review of two-phase flow instability,” Nucl. Eng. Des. 25, 165–192 (1973).

    Article  Google Scholar 

  7. Y. Xiao, F. Guangming, and S. Zhongning, “Study on flow characteristics in an open two-phase natural circulation loop,” Ann. Nucl. Energy 104, 291–300 (2017).

    Article  Google Scholar 

  8. V. A. Fedorov and O. O. Mil’man, Thermo-Hydraulic Self-Oscillations and Instability in Heat Exchange Systems with Two-Phase Flow (Mosk. Energ. Inst., Moscow, 1998) [in Russian].

    Google Scholar 

  9. A. M. Kutepov, L. S. Sterman, and N. G. Styushin, Hydrodynamics and Heat Transfer During Vaporization: Textbook for Higher Education Schools, 3rd ed. (Vysshaya Shkola, Moscow, 1986) [in Russian].

    Google Scholar 

  10. D. A. Labuntsov, Physical Fundamentals of Power Engineering: Selected Works on Heat Transfer, Hydrodynamics, Thermodynamics (Mosk. Energ. Inst., Moscow, 2000) [in Russian].

    Google Scholar 

  11. D. A. Labuntsov and V. V. Yagov, Mechanics of Two-Phase Media (Mosk. Energ. Inst., Moscow, 2007) [in Russian].

    Google Scholar 

  12. J. A. R. Henry, S. D. Morris, and A. M. MacDonald, “Momentum flux during sub-atmospheric two-phase flow through a pipe,” in Proc. the 7th Int. Heat Transfer Conf., München, Germany, Sept. 6–10, 1982 (Hemisphere, Washington, DC, 1982), Vol. 5, pp. 293–299.

  13. Fluorinert Electronic Liquid FC-723M, 2000, 3M Specialty Materials.

  14. B. S. Petukhov, L. G. Genin, S. A. Kovalev, and S. L. Solov’ev, Heat Transfer in Nuclear Power Units (Mosk. Energ. Inst., Moscow, 2003) [in Russian].

    Google Scholar 

  15. R. I. Nigmatulin, Dynamics of Multiphase Media (Nauka, Moscow, 1987) [in Russian].

    Google Scholar 

  16. V. V. Yagov and M. V. Minko, “Entrained liquid fraction calculation in adiabatic disperse-annular flows at low rate in film,” Therm. Eng. 63, 288–293 (2016). https://doi.org/10.1134/S0040601516040108

    Article  Google Scholar 

  17. Y. Hsu, Teploperedacha 84 (3), 18–29 (1962).

    Google Scholar 

  18. V. V. Yagov, “Generic features and puzzles of nucleate boiling,” Int. J. Heat Mass Transfer. 52, 5241–5249 (2009). https://doi.org/10.1016/j.ijheatmasstransfer.2009.03.071

    Article  Google Scholar 

  19. V. V. Yagov, Heat Transfer in Single-Phase Media and With Phase Transformations (Mosk. Energ. Inst., Moscow, 2014) [in Russian].

    Google Scholar 

  20. V. V. Yagov and M. V. Minko, “Heat transfer in two-phase flow at high reduced pressures,” Therm. Eng. 58, 283–294 (2011).

    Article  Google Scholar 

  21. O. N. Kaban’kov, L. A. Sukomel, N. O. Zubov, and V. V. Yagov, “Experimental study of thermo-hydraulic characteristics of natural circulation loop at water and FC-72 boiling under atmospheric pressure,” J. Phys.: Conf. Ser. 891. 012019 (2017).

    Google Scholar 

  22. O. N. Kaban’kov, L. A. Sukomel, V. V. Yagov, and N. O. Zubov, “Unstable circulation regimes during water boiling in a thermosyphon loop under atmospheric pressure,” Heat Pipe Sci. Technol., Int. J. 7, 31–44 (2016).

    Google Scholar 

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Authors and Affiliations

  1. National Research University Moscow Power Engineering Institute, 111250, Moscow, Russia

    V. V. Yagov, N. O. Zubov, O. N. Kaban’kov & L. A. Sukomel

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  1. V. V. Yagov
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  2. N. O. Zubov
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  3. O. N. Kaban’kov
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  4. L. A. Sukomel
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Correspondence to V. V. Yagov or O. N. Kaban’kov.

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Translated by V. Filatov

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Yagov, V.V., Zubov, N.O., Kaban’kov, O.N. et al. Experimental and Calculated Investigation of a Natural Circulation Loop’s Thermal-Hydraulic Characteristics. Therm. Eng. 66, 477–490 (2019). https://doi.org/10.1134/S0040601519070103

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  • DOI: https://doi.org/10.1134/S0040601519070103

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