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Abstract

A simple one dimensional numerical method is presented for the evaluation of the steady state behaviour of a two phase natural circulation loop. This method is applicable for loop consisting of two vertical limbs connected by point heat source and sink. In this work, Thermo-physical properties are considered as per the loop fluid state. The influence of following parameters such as heat input, inlet subcooling at heat source, loop diameter and height on the loop performance is analysed. Results show that mass flow rate increases with heat input. However, with the increase in heat input, mass flow rate increases initially up to a peak value and thereafter decreases. Also, the increase of loop diameter increases the mass flow rate for all heat inputs. However, increase of loop height has peculiar effect.

References

1. Archana, V., Vaidya, A. M., & Vijayan, P. K. (2015). Numerical modeling of supercritical CO2 natural circulation loop. Nuclear Engineering and Design, 293, 330–345. http://doi.org/10.1016/j.nucengdes.2015.07.030

2. Chen, K. S. (1991). An experimental study of steady-state behavior. Energy Conversion and Management, 31(6), 553–559.

3. Chen, K. S., & Chang, Y. R. (1988). Steady-state analysis of two-phase natural circulation loop. International Journal of Heat and Mass Transfer, 31(5), 931–940. http://doi.org/10.1016/0017-9310(88)90082-8

4. Chen, L., Zhang, X.-R., & Jiang, B. (2014). Effects of Heater Orientations on the Natural Circulation and Heat Transfer in a Supercritical CO2 Rectangular Loop. Journal of Heat Transfer, 136(May 2014), 52501. http://doi.org/10.1115/1.4025543

5. Close, D. J. (1962). The performance of solar water heaters with natural circulation. Solar Energy, 6(1), 33–40. http://doi.org/10.1016/0038-092X(62)90096-8

6. Dewangan, K. K., & Das, P. K. (2018). Assessing the effect of flashing on steady state behavior and Ledinegg instability of a two phase rectangular natural circulation loop. International Journal of Heat and Mass Transfer, 116, 218–230. http://doi.org/10.1016/j.ijheatmasstransfer.2017.08.119

7. Hagen, T.H.J.J. van der; Bragt, D.D.B. van; Kaa, F.J. van der; Killian, D.; Wouters, J.A.A.; Karuza, J.; Nissen, W.H.M.; Stekelenburg, A. J. C. (1997). Exploring the Dodewaard Type-I and Type-II stability: from start-up to shut-down, from stable to unstable. Annals of Nuclear Energy, 28(12), 659–669.

8. Heisler, M. P. (1982). Development of scaling requirements for natural convection liquid-metal fast breeder reactor shutdown heat removal test facilities. Nuclear Science and Engineering, 80, 347–359.

9. Lee, Sang Yong, M. I. (1990). Characteristics of two-phase natural circulation in Freon-113 boiling loop, 121, 69–81.

10. Rao, N. M., Sekhar, C. C., Maiti, B., & Das, P. K. (2006). Steady-state performance of a two-phase natural circulation loop. International Communications in Heat and Mass Transfer, 33(8), 1042–1052. http://doi.org/10.1016/j.icheatmasstransfer.2006.04.012

11. Shitzer, A., Kalmanoviz, D., Zvirin, Y., & Grossman, G. (1979). Experiments with a flat plate solar water heating system in thermosyphonic flow. Solar Energy, 22(1), 27–35. http://doi.org/10.1016/0038-092X(79)90056-2

12. Sudheer, S. V. S., & Kumar, K. K. (2018). Two-phase natural circulation loop behaviour at atmospheric and subatmospheric conditions, 0(0), 1–14. http://doi.org/10.1177/0954408918787401

Keywords

Point heat source, Two phase mixture, Quality, Flashing.