Session: 08-03: Computational Fluid Dynamics (CFD) and Applications - III

Paper Number: 134953

134953 - Research on Natural Frequency Characteristics of Spiral Tube Bundles 

Abstract: 

Liquid metal reactors(LMR),with the significant advantages in high safety and good economic benefits, has obvious advantages and broad application prospects in the fourth generation nuclear power systems. Spiral tube steam generator is one of the most important equipment in LMR, which are composed of spiral heat transfer tubes, inner and outer cylinders, feedwater headers, steam headers, and other structures. Due to their compact structure and high heat transfer efficiency, they are conducive to equipment miniaturization and have been widely used in different reactors in various countries. Due to the impact of the shell side fluid in the steam generator on the tube bundle, it is inevitable to cause flow induced vibration(FIV), resulting in thinning or even rupture of the tube wall, thereby shortening the service life or even failure of the steam generator. Therefore, the study of the vibration characteristics of spiral tube bundles is of great significance. The natural frequency of the tube bundle is an important parameter in FIV analysis. The heat transfer tubes of the spiral tube steam generator are made of spiral winding, and the positions between adjacent tubes are complex and variable. The winding direction between adjacent layers of the spiral heat transfer tubes can be in the same or opposite direction, so their spatial structure is complex. This article simulates and calculates the natural frequency of spiral heat transfer tubes in air and lead bismuth, and studies the influence of geometric structural parameters on their natural frequency. Based on simplifying constraints at both ends of the spiral tube bundles to fixed support, the computational fluid dynamics (CFD) simulation was carried out to reveal the effect mechanism of support number and spiral radius, on natural frequency of spiral tube bundles in air. The results indicate that an increase in spiral radius leads to a decrease in natural frequency, while an increase in support number leads to a significant increase in natural frequency. Therefore, we can improve the stability of the spiral tube bundles by increasing support number or reducing spiral radius. Through CFD simulation calculation, the influence mechanism of tube bundle structural parameters on the natural frequency of spiral tube bundles in liquid metal environments was studied. The increase of layer pitch ratio and the same layer pitch ratio led to an increase in natural frequency. The research results provide data reference for the prediction of the natural frequency of heat transfer tubes and the study of FIV of tube bundles, which are of great significance for avoiding the failure of heat transfer tubes.

Presenting Author: Xiaoxi Li Harbin Engineering University

Presenting Author Biography: Li Xiaoxi, Ph.D student at the School of Nuclear Science and Technology, Harbin Engineering University, with a main research focus on flow induced vibration of reactor components.

Authors:

Xiaoxi Li Harbin Engineering University
Jiming Wen Harbin Engineering University
Puzhen Gao Harbin Engineering University
Yibo Yin Harbin Engineering University