Estimating steady state and transient characteristics of molten salt natural circulation loop using CFD
-
J. Y. Kudariyawar
Abstract
The steady state and transient characteristics of a molten salt natural circulation loop (NCL) are obtained by 3D CFD simulations. The working fluid is a mixture of NaNO3 and KNO3 in 60:40 ratio. Simulation is performed using PHOENICS CFD software. The computational domain is discretized by a body fitted grid generated using in-built mesh generator. The CFD model includes primary side. Primary side fluid is subjected to heat addition in heater section, heat loss to ambient (in piping connecting heater and cooler) and to secondary side (in cooler section). Reynolds Averaged Navier Stokes equations are solved along with the standard k-∊ turbulence model. Validation of the model is done by comparing the computed steady state Reynolds number with that predicted by various correlations proposed previously. Transient simulations were carried out to study the flow initiations transients for different heater powers and different configurations. Similarly the “power raising” transient is computed and compared with in-house experimental data. It is found that, using detailed information obtained from 3D transient CFD simulations, it is possible to understand the physics of oscillatory flow patterns obtained in the loop under certain conditions.
Kurzfassung
Die stationären und transienten Eigenschaften von Salzschmelze im Naturumlauf wurden mit Hilfe von 3D-CFD-Simulationen bestimmt. Die Salzschmelze ist eine Mischung aus NaNO3 und KNO3 im Verhältnis 60:40. Die Simulation wurde mit Hilfe der PHOENICS-CFD-Software durchgeführt. Das CFD-Modell beinhaltet den Primärseitenbereich. Im Primärseitenbereich wird die Flüssigkeit im Heizabschnitt zusätzlich erwärmt und gibt in anderen Bereichen Wärme an die Umgebung und an den Sekundärseitenbereich ab. Reynolds-gemittelte Navier-Stokes-Gleichungen wurden zusammen mit dem Standard k-∊ Turbulenzmodell gelöst. Die Validierung des Modells wird durchgeführt durch Vergleich der berechneten Reynolds-Zahl im stationären Zustand mit der Reynolds-Zahl, die vorher durch verschiedene, vorgeschlagene Korrelationen vorhergesagt wurde. Transiente Simulationen wurden durchgeführt um die Strömungstransienten für verschiedene Heizleistungen und unterschiedliche Konfigurationen zu untersuchen. Dabei zeigte sich, dass es bei Anwendung der aus den 3D-transienten CFD-Simulationen erhaltenen detaillierten Information möglich ist die Physik des unidirektionalen und bi-direktionalen oszillatorischen Strömungsverhaltens zu verstehen.
References
1 Swapnalee, B. T.; Vijayan, P. K.: A generalized flow equation for single phase natural circulation loops obeying multiple friction laws. Int. J. Heat and Mass transfer54 (2011) 2618–262910.1016/j.ijheatmasstransfer.2011.01.023Search in Google Scholar
2 Welander, P.: On the oscillatory instability of a differentially heated fluid loop. J. Fluid Mech.29 (1967) 17–3010.1017/S0022112067000606Search in Google Scholar
3 Creveling, H. F.; De Paz, J. F.; Baladi, J. Y.;Schoenhals, R. J.: Stability characteristics of a single-phase free convection loop. J. Fluid Mech.67 (1975) 65–8410.1017/S0022112075000171Search in Google Scholar
4 Huang, B. J.; Zelaya, R.: Heat transfer behaviour of a rectangular thermosiphon loop. J. Heat Transfer110 (1988) 487–49310.1115/1.3250512Search in Google Scholar
5 Vijayan, P. K.; Austregesilo, H.: Scaling laws for single-phase natural circulation loops. J. Nucl. Eng. Des.152 (1994) 331–34710.1016/0029-5493(94)90095-7Search in Google Scholar
6 Vijayan, P. K.; Bhojwani, V. K.; Bade, M. H.; Sharma, M.; Nayak, A. K.; Saha, D.; Sinha, R. K.: Investigation on the effect of heater and cooler orientation on the steady state transient and stability behavior of single-phase natural circulation in a rectangular loop. Reactor Engineering Division, Bhabha Atomic Research Centre, Mumbai, India, 2001, BARC/2001/E/034Search in Google Scholar
7 Vijayan, P. K.: Experimental observations on general trends of the steady state and stability behavior of single-phase natural circulation loops. Nucl. Eng. Des.215 (2002) 139–15210.1016/S0029-5493(02)00047-XSearch in Google Scholar
8 Vijayan, P. K.; Sharma, M.; Saha, D.: Steady state and stability characteristics of single-phase natural circulation in a rectangular loop with different heater and cooler orientations. Exp. Therm. Fluid Sci.31 (2007) 925–94510.1016/j.expthermflusci.2006.10.003Search in Google Scholar
9 Pilkhwal, D. S.; Ambrosini, W.; Forgione, N.; Vijayan, P. K.; Saha, D.; Ferreri, J. C.: Analysis of the unstable behavior of a single-phase natural circulation loop with one-dimensional and computational fluid-dynamic models. Ann. Nucl. Energy34 (2007) 339–35510.1016/j.anucene.2007.01.012Search in Google Scholar
10 Kumar, N.; Doshi, J. B.; Vijayan, P. K.: Investigation on the role of mixed convection and wall friction factor in single-phase natural circulation loop dynamics. Annals of Nuclear Energy38 (2011) 2247–227010.1016/j.anucene.2011.06.004Search in Google Scholar
11 Wang, J. Y.; Chuang, T. J.; Ferng, Y. M.: CFD investigating flow and heat transfer characteristics in a natural circulation loop. Annals of Nuclear Energy58 (2013) 65–7110.1016/j.anucene.2013.01.015Search in Google Scholar
12 Keller, J.: Periodic oscillations in a model of thermal convection. J. Fluid Mech.26 (1966) 599–60610.1017/S0022112066001423Search in Google Scholar
13 Bau, H. H.; Torrance, K. E.: Transient and steady behaviour of an open, symmetrically-heated, free convection loop. Int. J. Heat Mass Transfer24 (1981) 597–60910.1016/0017-9310(81)90004-1Search in Google Scholar
14 Mertol, A.; Greif, R.: The transient, Steady state and stability behaviour of a thermosiphon with throughflow. Int. J. Heat Mass Transfer24 (1981) 621–63310.1016/0017-9310(81)90006-5Search in Google Scholar
15 Mertol, A.; Greif, R.; Zvirin, Y.: Two-Dimensional study of Heat Transfer and Fluid Flow in a Natural Convection Loop. J. Heat Transfer104 (1982) 508–51410.1115/1.3245122Search in Google Scholar
16 Chen, K.: On the oscillatory instability of closed-loop thermosyphons. Trans. ASME J. Heat transfer107 (1985) 826–83210.1115/1.3247510Search in Google Scholar
17 Hart, J. E.: Observations of Complex Oscillations in a Closed Thermosyphon. J. Heat Transfer107 (1985) 833–83910.1115/1.3247511Search in Google Scholar
18 Hart, J. E.: A Model of Flow in a Closed-Loop Thermosyphon Including the Soret Effect. J. Heat Transfer107 (1985) 840–84910.1115/1.3247512Search in Google Scholar
19 Zvirin, Y.: The instability associated with the onset of motion in a thermosiphon. Int. J. Heat Mass Transfer28 (1985) 2105–211110.1016/0017-9310(85)90104-8Search in Google Scholar
20 Lavine, A. S.; Greif, R. J.; Humphrey, A. C.: A three-dimensional analysis of natural convection in a toroidal loop-the effect of Grashof number. Int. J. Heat Mass Transfer30 (1987) 251–26210.1016/0017-9310(87)90113-XSearch in Google Scholar
21 Bernier, M. A.; Baliga, B. R.: A 1-D/2-D model and experimental results for a closed-loop thermosiphon with vertical heat transfer sections. Int. J. Heat Mass Transfer35 (1992) 2969–298210.1016/0017-9310(92)90317-LSearch in Google Scholar
22 Vijayan, P. K.; Austregesilo, H.; Teschendorff, V.: Simulation of the unstable oscillatory behavior of single-phase natural circulation with repetitive flow reversals in a rectangular loop using computer code ATHLET. Nucl. Eng. Des.155 (1995) 623–64110.1016/0029-5493(94)00972-2Search in Google Scholar
23 Ambrosini, W.; Ferreri, J. C.: The effect of truncation error on numerical prediction of stability boundaries in a natural circulation loop. Nucl. Eng. Des.183 (1998) 53–7610.1016/S0029-5493(98)00157-5Search in Google Scholar
24 Ambrosini, W.; Ferreri, J. C.: Stability analysis of single phase thermosyphon loops by finite difference numerical methods. Nucl. Eng. Des.201 (2000) 11–2310.1016/S0029-5493(00)00262-4Search in Google Scholar
25 Ambrosini, W.; Ferreri, J. C.: Prediction of stability of one-dimensional natural circulation with a low diffusion numerical scheme. Ann. Nucl. Energy30 (2003) 1505–153710.1016/S0306-4549(03)00119-1Search in Google Scholar
26 Mousavian, S. K.; Misale, M.; D’Auria, F.; Salehi, M. A.: Transient and stability analysis in single-phase natural circulation. Ann. Nucl. Energy31 (2004) 1177–119810.1016/j.anucene.2004.01.005Search in Google Scholar
27 Basu, D.; Bhattacharyya, S.; Das, P. K.: Effect of heat loss to ambient on steady-state behaviour of a single-phase natural circulation loop. App. Therm. Eng.27 (2007) 1432–144410.1016/j.applthermaleng.2006.10.004Search in Google Scholar
28 Basu, D.; Bhattacharyya, S.; Das, P. K.: Dynamic response of a single-phase rectangular natural circulation loop to different excitations of input power. Int. J. Heat and Mass Transfer65 (2013) 131–14210.1016/j.ijheatmasstransfer.2013.06.006Search in Google Scholar
29 Alstad, C. D.; Isbin, H. S.; Amundson, N. R.; Silvers, J. P.: Transient Behavior of Single-phase natural-circulation Loop Systems. A.I.Ch.E. Journal1 (1955) 417–42510.1002/aic.690010407Search in Google Scholar
30 Misale, M.; Garibaldi, P.; Tarozzi, L.; Barozzi, G. S.: Influence of thermal boundary conditions on the dynamic behaviour of a rectangular single-phase natural circulation loop. Int. J. Heat and Fluid Flow32 (2011) 413–42310.1016/j.ijheatfluidflow.2010.12.003Search in Google Scholar
31 XuejunZhang; JunTian; KangchengXu; YiciGao: Thermodynamic Evaluation of Phase Equilibria in NaNO3-KNO3 System. Journal of Phase Equilibria24 (2003)10.1361/105497103770330091Search in Google Scholar
32 Kearney, D.; Kelly, B.; Herrmann, U.; Cable, R.; Pacheco, J.; Mahoney, J.; Price, H.; Blake, D.; Nava, P.; Potrovitza, N.: Engineering aspects of a molten salt heat transfer fluid in a trough solar field. Energy29 (2004) 861–87010.1016/S0360-5442(03)00191-9Search in Google Scholar
33 Ferri, R.; Cammi, A.; Mazzei, D.: Molten salt mixture properties in RELAP5 code for Thermodynamic solar applications. Int. J. Therm. Sci.47 (2008) 1676–168710.1016/j.ijthermalsci.2008.01.007Search in Google Scholar
34 CHAM Ltd., 2011, PHOENICS User ManualSearch in Google Scholar
35 Bird, R. Byron; Stewart, W. E.; Lightfoot, E. N.: Transport Phenomena, second edition, John Wiley & Sons (Asia) Pte. Ltd., SingaporeSearch in Google Scholar
36 Nissan, D. A.: Thermophysical Properties of the Equimolar Mixture NaNO3-KNO3 from 300 to 600°C. J. Chem. Eng. Data27 (1982) 269–27310.1021/je00029a012Search in Google Scholar
37 Serrano-Lopez, R.; Fradera, J.; Cuesta-Lopez, S.: Molten salts database for energy applications. Chem. Eng. and Processing: Process Intensification73 (2013) 87–10210.1016/j.cep.2013.07.008Search in Google Scholar
38 Incropera, F. P.; DeWitt, D. P.: Fundamentals of Heat and Mass Transfer. John Wiley & Sons, New York, 1996Search in Google Scholar
© 2015, Carl Hanser Verlag, München
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Evaluation of advanced displacement cross-sections for the major EUROFER constituents based on an atomistic modelling approach
- Tarapur atomic power station: analysis of station blackout scenario
- Estimating steady state and transient characteristics of molten salt natural circulation loop using CFD
- Thermal hydraulic analysis of ETRR-2 using RELAP5 code
- Transient performance during stopping the research reactor primary loop pump
- Neutronic performance calculations with alternative fluids in a hybrid reactor by using the Monte Carlo method
- A study on the criticality of modified neutron transport equation by using alternative scattering phase functions
- Production cross–section calculations of medical 32P, 117Sn, 153Sm and 186,188Re radionuclides used in bone pain palliation treatment
- Study on carbonated hydroxyapatite as a thermoluminescence dosimeter
- Social impact theory based modeling for security analysis in the nuclear fuel cycle
- Analysis of a homogenous and heterogeneous stylized half core of a CANDU reactor
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Evaluation of advanced displacement cross-sections for the major EUROFER constituents based on an atomistic modelling approach
- Tarapur atomic power station: analysis of station blackout scenario
- Estimating steady state and transient characteristics of molten salt natural circulation loop using CFD
- Thermal hydraulic analysis of ETRR-2 using RELAP5 code
- Transient performance during stopping the research reactor primary loop pump
- Neutronic performance calculations with alternative fluids in a hybrid reactor by using the Monte Carlo method
- A study on the criticality of modified neutron transport equation by using alternative scattering phase functions
- Production cross–section calculations of medical 32P, 117Sn, 153Sm and 186,188Re radionuclides used in bone pain palliation treatment
- Study on carbonated hydroxyapatite as a thermoluminescence dosimeter
- Social impact theory based modeling for security analysis in the nuclear fuel cycle
- Analysis of a homogenous and heterogeneous stylized half core of a CANDU reactor
