Experimental investigation of the impact of non-uniform pipe diameters on natural circulation and dimensionless flow in in a rectangular loop

Iwan Roswandi, Agus Sunjarianto Pamitran, Mulya Juarsa, Arif Adtyas Budiman

Abstract


This experimental study investigates the effect of non-uniform pipe diameters on natural circulation flow within a rectangular loop related to non-dimensional numbers, such as the Reynolds number and the Grashof number. The study aims to understand how variations in pipe diameters influence natural circulation, which is critical for thermal engineering applications, including passive cooling systems for nuclear reactors and thermal management in electronic devices. Previous research by Vijayan et al., Garibaldi et al., and Elton et al. explored the impact of loop geometry on flow stability and heat transfer efficiency. In this study, a loop system with varying pipe diameters operates without a pump at atmospheric pressure. Data on fluid flow and temperature distribution were recorded at different temperature settings. The results show that fluid flow increases with temperature, decreasing fluid density and enhancing buoyancy forces. This increases the Reynolds number, reaching turbulent flow at 70°C throughout the loop. However, the 2-inch diameter hot leg remains in the transition region up to 90°C. The experimental correlation shows higher Grashof numbers than previous models, highlighting the significant impact of pipe diameter variations on buoyancy forces and flow transitions. These findings emphasize the importance of non-uniform pipe geometries in influencing natural circulation flow and its transition from laminar to turbulent flow, providing valuable insights for designing systems with non-uniform pipe configurations.

Keywords


Natural circulation, non-uniform diameter, Reynolds number, rectangular loop, buoyancy force

Full Text:

PDF

References


P. K. Vijayan, M. Sharma, and D. Saha, “Steady state and stability characteristics of single-phase natural circulation in a rectangular loop with different heater and cooler orientations,†Exp Therm Fluid Sci, vol. 31, no. 8, pp. 925–945, Aug. 2007, doi: 10.1016/j.expthermflusci.2006.10.003.

P. K. Vijayan, A. K. Nayak, D. Saha, and M. R. Gartia, “Effect of loop diameter on the steady state and stability behaviour of single-phase and two-phase natural circulation loops,†Science and Technology of Nuclear Installations, vol. 2008, 2008, doi: 10.1155/2008/672704.

P. Garibaldi and M. Misale, “Experiments in single-phase natural circulation miniloops with different working fluids and geometries,†J Heat Transfer, vol. 130, no. 10, Oct. 2008, doi: 10.1115/1.2948393.

M. Misale, “Dynamic behaviour of a rectangular single-phase natural circulation loop: influence of loop inclination,†2010. [Online]. Available: https://www.researchgate.net/publication/268264008

D. Hariyanto, S. Permana, and Suprijadi, “Experimental and simulation approach of the loop geometry effect on the natural circulation system of the advanced nuclear reactor,†Int J Energy Res, vol. 45, no. 8, pp. 11892–11903, Jun. 2021, doi: 10.1002/er.5903.

M. Misale, J. A. Bocanegra, and A. Marchitto, “Thermo-hydraulic performance of connected single-phase natural circulation loops characterized by two different inner diameters,†International Communications in Heat and Mass Transfer, vol. 125, Jun. 2021, doi: 10.1016/j.icheatmasstransfer.2021.105309.

B. T. Swapnalee and P. K. Vijayan, “A generalized flow equation for single phase natural circulation loops obeying multiple friction laws,†Int J Heat Mass Transf, vol. 54, no. 11–12, pp. 2618–2629, May 2011, doi: 10.1016/j.ijheatmasstransfer.2011.01.023.

N. Kumar, J. B. Doshi, and P. K. Vijayan, “Investigations on the role of mixed convection and wall friction factor in single-phase natural circulation loop dynamics,†Ann Nucl Energy, vol. 38, no. 10, pp. 2247–2270, Oct. 2011, doi: 10.1016/j.anucene.2011.06.004.

R. Saha, S. Sen, S. Mookherjee, K. Ghosh, A. Mukhopadhyay, and D. Sanyal, “Experimental and Numerical Investigation of a Single-Phase Square Natural Circulation Loop,†J Heat Transfer, vol. 137, no. 12, Dec. 2015, doi: 10.1115/1.4030926.

M. Misale, “Experimental study on the influence of power steps on the thermohydraulic behaviour of a natural circulation loop,†Aug. 01, 2016, Elsevier Ltd. doi: 10.1016/j.ijheatmasstransfer.2016.04.036.

S. M. Seyyedi, N. Sahebi, A. S. Dogonchi, and M. Hashemi-Tilehnoee, “Numerical and experimental analysis of a rectangular single-phase natural circulation loop with asymmetric heater position,†Int J Heat Mass Transf, vol. 130, pp. 1343–1357, Mar. 2019, doi: 10.1016/j.ijheatmasstransfer.2018.11.030.

M. Misale, J. A. Bocanegra, D. Borelli, and A. Marchitto, “Experimental analysis of four parallel single-phase natural circulation loops with small inner diameter,†Appl Therm Eng, vol. 180, Nov. 2020, doi: 10.1016/j.applthermaleng.2020.115739.

D. N. Elton, U. C. Arunachala, and P. K. Vijayan, “Investigations on the dependence of the stability threshold on different operating procedures in a single-phase rectangular natural circulation loop,†Int J Heat Mass Transf, vol. 161, Nov. 2020, doi: 10.1016/j.ijheatmasstransfer.2020.120264.

S. Bello, P. Gao, and Y. Lin, “Closed-loop experimental investigation of single-phase natural circulation flow phenomena based on temperature and heating power variations,†Ann Nucl Energy, vol. 151, Feb. 2021, doi: 10.1016/j.anucene.2020.107809.

D. N. Elton, U. C. Arunachala, and P. K. Vijayan, “Stability enhancement in large diameter rectangular natural circulation loops using flow restrictors,†International Communications in Heat and Mass Transfer, vol. 126, Jul. 2021, doi: 10.1016/j.icheatmasstransfer.2021.105412.

D. N. Elton, U. C. Arunachala, and P. K. Vijayan, “Stabilization of single phase rectangular natural circulation loop of larger diameter using orifice plate,†International Communications in Heat and Mass Transfer, vol. 137, Oct. 2022, doi: 10.1016/j.icheatmasstransfer.2022.106216.

Westinghouse Electric Company, AP1000 Design Control Document, Tier 2 Material, Revision 19, U.S. Nuclear Regulatory Commission, Washington, DC, USA, June 2011.

A. Crabtree and M. Siman-Tov, "Thermophysical properties of saturated light and heavy water for advanced neutron source applications," Oak Ridge National Laboratory, Oak Ridge, TN, USA, Tech. Rep., 1993

B. R. Munson, D. F. Young, and T. H. Okiishi, Fundamentals of Fluid Mechanics, 6th ed. Hoboken, NJ: John Wiley & Sons, 2009.

P. K. Vijayan, “Experimental observations on the general trends of the steady state and stability behaviour of single-phase natural circulation loops,†2002. [Online]. Available: www.elsevier.com/locate/nucengdes

J. Y. Wang, T. J. Chuang, and Y. M. Ferng, “CFD investigating flow and heat transfer characteristics in a natural circulation loop,†Ann Nucl Energy, vol. 58, pp. 65–71, 2013, doi: 10.1016/j.anucene.2013.01.015.

I. Roswandi et al., “Investigation of Natural Circulation Flow Under Steady-State Conditions Using a Rectangular Loop,†Teknologi Reaktor Nuklir Tri Dasa Mega vol. 26, no. 2, pp. 77–86, 2024, doi: 10.55981/tdm.2024.7055.




DOI: http://dx.doi.org/10.30811/jpl.v23i3.6666

Refbacks

  • There are currently no refbacks.


Bookmark and Share


Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Lisensi Creative Commons

Ciptaan disebarluaskan di bawah Lisensi Creative Commons Atribusi-BerbagiSerupa 4.0 Internasional .

 

Alamat Surat :

Politeknik Negeri Lhokseumawe
Jl. Banda Aceh-Medan Km 280
Buketrata, Lhokseumawe, 24301, Aceh, Indonesia