Large Eddy Simulation of 5-Tube Bundle Helical Coil Steam Generator Test Section

2018 ◽  
Author(s):  
Mustafa Alper Yildiz ◽  
Elia Merzari ◽  
Yassin A. Hassan
Keyword(s):  
Large Eddy Simulation ◽  
Steam Generator ◽  
Test Section ◽  
Tube Bundle ◽  
Flow Behavior ◽  
Spectral Element ◽  
Helical Coil ◽  
Tube Heat Exchanger ◽  
Eddy Simulation ◽  
Large Eddy

Helical Coil Steam Generator (HCSG) is a specific type of shell and tube heat exchanger known for having a higher heat transfer coefficient than many other designs. For this reason, they are considered in Small Modular Reactor (SMR) and High Temperature Reactor (HTR) designs. Investigation of flow behavior in HTRs is important for better design. To investigate the flow on the shell side, five rod HCSG test section was built in Texas A&M University. Experiments were conducted at Reynolds number of approximately 9000. The spectral element code NEK5000 was used to do high fidelity large-eddy simulation (LES) of the test section to validate against experimental results. In this paper preliminary simulation results were presented. Pressure drop in preliminary results with seventh and ninth order polynomial expansion was consistent with experimental data.

Large Eddy Simulation of the Flow Behavior in a Simplified Helical Coil Steam Generator

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Jonathan K. Lai ◽  
Elia Merzari ◽  
Yassin A. Hassan
Keyword(s):  
Large Eddy Simulation ◽  
Steam Generator ◽  
Flow Behavior ◽  
Spectral Element ◽  
Helical Coil ◽  
Eddy Simulation ◽  
Velocity Statistics ◽  
Turbulent Characteristics ◽  
Large Eddy ◽  
Pod Analysis

Large eddy simulation (LES) is conducted for the flow over the shell side of a helical coil steam generator (HCSG) heat exchanger. Simulations are conducted on a simplified experimental test section that represents a one-column region of the helical coils using half-rods. Although the rods are wall-bounded, the flow still exhibits the turbulent characteristics and fluctuations from vortex shedding that one would expect from crossflow around a cylinder. The spectral element, computational fluid dynamics (CFD) code Nek5000, is used to capture the physics, and the results are compared with particle image velocimetry (PIV) measurements. In order to ensure that the turbulence is resolved, analysis is conducted by using the Taylor length scales and normalized wall distance. Sensitivity to the inlet boundary conditions (BCs) and the spatial discretization for different polynomial order solutions are also studied, finding only minor differences between each case. Pressure drop and velocity statistics show reasonable agreement with PIV. Proper orthogonal decomposition (POD) analysis reveals that the primary modes are similar between experiment and simulation, although the LES predicts higher turbulent kinetic energy than does PIV. Overall, the study establishes the resolution and resources required in order to conduct a high-fidelity simulation over 12 helical rods.

Large Eddy Simulation of a Helical Coil Steam Generator Test Section

2017 ◽  
Author(s):  
Jonathan K. Lai ◽  
Elia Merzari ◽  
Marilyn Delgado ◽  
Samuel J. Lee ◽  
Saya Lee ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Large Eddy Simulation ◽  
Steam Generator ◽  
Test Section ◽  
Helical Coil ◽  
Reynolds Stresses ◽  
Eddy Simulation ◽  
High Heat Transfer ◽  
Large Eddy ◽  
Inlet Conditions

The helical coil steam generator (HCSG) is a compact heat exchanger that can have high heat transfer even when the pressure drop is low. This makes it advantageous in small modular reactors and high-temperature reactor designs. In order to investigate the fluid phenomena around these helical banked tubes, a test section was built at Texas A&M University to represent flow across two half-rods within HCSG. This study focuses on the validation of large eddy simulation (LES) for this particular geometry. Pressure tap and particle image velocimetry (PIV) measurements have been recorded at an inlet Reynolds number of 8643, and both mean and fluctuating data is compared with the numerical results. The highly scalable spectral-element code Nek5000 has been used to produce the LES calculations. First, simulations of varying polynomial order expansions are made to determine the spatial resolution required to capture the turbulent scales. Then, simulations with different inlet conditions are compared with experimental data. The pressure drop shows good agreement with pressure tap measurements while velocity shows similar characteristics with PIV. Furthermore, the components of the Reynolds stresses and modes from proper orthogonal decomposition have been developed to validate the physics captured.

scholarly journals Flow-induced vibration analysis of a helical coil steam generator experiment using large eddy simulation

2017 ◽  
Vol 322 ◽  
pp. 547-562 ◽  
Author(s):  
Haomin Yuan ◽  
Jerome Solberg ◽  
Elia Merzari ◽  
Adam Kraus ◽  
Iulian Grindeanu
Keyword(s):  
Large Eddy Simulation ◽  
Steam Generator ◽  
Vibration Analysis ◽  
Helical Coil ◽  
Flow Induced Vibration ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulation of the differentially heated cubic cavity flow by the spectral element method

2013 ◽  
Vol 86 ◽  
pp. 210-227 ◽  
Author(s):  
Christoph Bosshard ◽  
Abdelouahab Dehbi ◽  
Michel Deville ◽  
Emmanuel Leriche ◽  
Riccardo Puragliesi ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Spectral Element Method ◽  
Cavity Flow ◽  
Spectral Element ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Element Method

Large eddy simulation study of turbulent flow around smooth and rough domes

2013 ◽  
Vol 227 (12) ◽  
pp. 2686-2700 ◽  
Author(s):  
N Kharoua ◽  
L Khezzar
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Flow Behavior ◽  
Pressure Coefficient ◽  
Horseshoe Vortex ◽  
Scale Model ◽  
Stream Velocity ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulation of turbulent flow around smooth and rough hemispherical domes was conducted. The roughness of the rough dome was generated by a special approach using quadrilateral solid blocks placed alternately on the dome surface. It was shown that this approach is capable of generating the roughness effect with a relative success. The subgrid-scale model based on the transport of the subgrid turbulent kinetic energy was used to account for the small scales effect not resolved by large eddy simulation. The turbulent flow was simulated at a subcritical Reynolds number based on the approach free stream velocity, air properties, and dome diameter of 1.4 × 105. Profiles of mean pressure coefficient, mean velocity, and its root mean square were predicted with good accuracy. The comparison between the two domes showed different flow behavior around them. A flattened horseshoe vortex was observed to develop around the rough dome at larger distance compared with the smooth dome. The separation phenomenon occurs before the apex of the rough dome while for the smooth dome it is shifted forward. The turbulence-affected region in the wake was larger for the rough dome.

scholarly journals Modal explicit filtering for large eddy simulation in discontinuous spectral element method

2019 ◽  
Vol 3 ◽  
pp. 100024
Author(s):  
Zia Ghiasi ◽  
Jonathan Komperda ◽  
Dongru Li ◽  
Ahmad Peyvan ◽  
David Nicholls ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Spectral Element Method ◽  
Spectral Element ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Element Method
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