Abstract

The present study focuses on the analysis of the flow in the shell side of a 24-degree cut helical coil steam generator (HCSG) with large eddy simulation (LES). In the study, the open source, high-order spectral element CFD code Nek5000 was employed for numerical simulation. LES was performed at a Reynolds number of 9000 based on the inlet velocity and tube diameter. Spectral analysis was carried out along the tube bundle to investigate vortex shedding and to reveal shedding frequencies in HCSGs. Wavelet analysis was carried out to determine the time-frequency information of the fluctuating velocities in the domain. Flow was decomposed into modes with proper orthogonal decomposition, which revealed most energetic coherent structures in the flow and evolution of the modes in time. Multi-resolution dynamic mode decomposition was employed for the wavelet-inspired analysis of the coherent structures in the domain. For the validation of Nek5000 in complex geometries, results from the numerical simulation were compared with experiments conducted at Texas A&M University.

Publications

1. Mustafa Alper Yildiz, Elia Merzari, and Yassin Hassan, 2019. “Spectral and Modal Analysis of the Flow in a Helical Coil Steam Generator Experiment with Large Eddy Simulation”. International Journal of Heat and Fluid Flow 80.108486, pp. 1–16. Read Article

2. Mustafa Alper Yildiz, Haomin Yuan, Elia Merzari, and Yassin Hassan, 2019, “Numerical Simulation of Isothermal Flow Across Slant Five-Tube Bundle with Spectral Element Method Code Nek5000,” Nuclear Technology, pp. 1–11. Read Article

3. Haomin Yuan, Mustafa Alper Yildiz et al. (2019). “Spectral Element Applications in Complex Nuclear Reactor Geometries: Tet-to-Hex Meshing”. Nuclear Engineering and Design 357.110422, pp. 1–14. Read Article

4. Haomin Yuan, Mustafa Alper Yildiz et al. (2019). “Applying tet-to-hex meshing method to complex nuclear reactor geometries for spectral element code”, 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH), 2019, Portland, OR.

5. Mustafa Alper Yildiz, Elia Merzari, Yassin Hassan, Marilyn Delgado, "Study of Vortex Shedding in Helical Coil Steam Generator”, 2019 ANS Summer Meeting, Minneapolis, MN.

6. Mustafa Alper Yildiz, Elia Merzari, Yassin Hassan,"Large Eddy Simulation of 5-Tube Bundle Helical Coil Steam Generator Test Section”, 26th International Conference on Nuclear Engineering ICONE-26, 2018, London, UK