# High-Fidelity Simulation of Flow-Induced Vibrations in Helical Steam Generators for Small Modular Reactors

## Abstract

Flow-induced vibration (FIV) is a widespread problem in energy systems as they rely on fluid movement for energy conversion. Vibrating structures may be damaged as fatigue or wear occur. Given the importance of reliable components in the nuclear industry, FIV has long been a major concern in the safety and operation of nuclear reactors. In particular, nuclear fuel rods and steam generators have been known to suffer from FIV and related failures. In this paper we discuss the use of the computational fluid dynamics code Nek5000 coupled to the structural code Diablo to simulate the flow in helical coil heat exchangers and associated FIV. In particular, one-way coupled calculations are performed, where pressure and tractions data are loaded into the structural model. The main focus of this paper is on validation of this capability. Fluid-only Nek5000 large eddy simulations are first compared against dedicated high-resolution experiments. Then, one-way coupled calculations are performed with Nek5000 and Diablo for two data sets that provide FIV data for validation. These calculations were aimed at simulating available legacy FIV experiments in helical steam generators in the turbulent buffeting regime. In this regime one-way coupling is judged sufficient since the pressure loads do not causemore »

- Authors:

- Publication Date:

- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)

- Sponsoring Org.:
- USDOE Office of Nuclear Energy - Nuclear Energy Advanced Modeling and Simulation (NEAMS)

- OSTI Identifier:
- 1510048

- DOE Contract Number:
- AC02-06CH11357

- Resource Type:
- Journal Article

- Journal Name:
- Nuclear Technology

- Additional Journal Information:
- Journal Volume: 205; Journal Issue: 1-2

- Country of Publication:
- United States

- Language:
- English

- Subject:
- Flow-Induced Vibration; Helical Coil Heat Exchangers; Large Eddy Simulation

### Citation Formats

```
Merzari, E., Yuan, H., Kraus, A., Obabko, A., Fischer, P., Solberg, J., Lee, S., Lai, J., Delgado, M., and Hassan, Y.
```*High-Fidelity Simulation of Flow-Induced Vibrations in Helical Steam Generators for Small Modular Reactors*. United States: N. p., 2019.
Web. doi:10.1080/00295450.2018.1490124.

```
Merzari, E., Yuan, H., Kraus, A., Obabko, A., Fischer, P., Solberg, J., Lee, S., Lai, J., Delgado, M., & Hassan, Y.
```*High-Fidelity Simulation of Flow-Induced Vibrations in Helical Steam Generators for Small Modular Reactors*. United States. doi:10.1080/00295450.2018.1490124.

```
Merzari, E., Yuan, H., Kraus, A., Obabko, A., Fischer, P., Solberg, J., Lee, S., Lai, J., Delgado, M., and Hassan, Y. Tue .
"High-Fidelity Simulation of Flow-Induced Vibrations in Helical Steam Generators for Small Modular Reactors". United States. doi:10.1080/00295450.2018.1490124.
```

```
@article{osti_1510048,
```

title = {High-Fidelity Simulation of Flow-Induced Vibrations in Helical Steam Generators for Small Modular Reactors},

author = {Merzari, E. and Yuan, H. and Kraus, A. and Obabko, A. and Fischer, P. and Solberg, J. and Lee, S. and Lai, J. and Delgado, M. and Hassan, Y.},

abstractNote = {Flow-induced vibration (FIV) is a widespread problem in energy systems as they rely on fluid movement for energy conversion. Vibrating structures may be damaged as fatigue or wear occur. Given the importance of reliable components in the nuclear industry, FIV has long been a major concern in the safety and operation of nuclear reactors. In particular, nuclear fuel rods and steam generators have been known to suffer from FIV and related failures. In this paper we discuss the use of the computational fluid dynamics code Nek5000 coupled to the structural code Diablo to simulate the flow in helical coil heat exchangers and associated FIV. In particular, one-way coupled calculations are performed, where pressure and tractions data are loaded into the structural model. The main focus of this paper is on validation of this capability. Fluid-only Nek5000 large eddy simulations are first compared against dedicated high-resolution experiments. Then, one-way coupled calculations are performed with Nek5000 and Diablo for two data sets that provide FIV data for validation. These calculations were aimed at simulating available legacy FIV experiments in helical steam generators in the turbulent buffeting regime. In this regime one-way coupling is judged sufficient since the pressure loads do not cause substantial displacements. It is also the most common source of vibration in helical steam generators at the low flows expected in integral pressurized water reactors. We discuss validation of two-way coupled experiments and benchmarks toward the simulation of fluid elastic instability. We briefly discuss the application of these methods to grid-to-rod fretting.},

doi = {10.1080/00295450.2018.1490124},

journal = {Nuclear Technology},

number = 1-2,

volume = 205,

place = {United States},

year = {2019},

month = {1}

}