Three-Dimensional Steady Simulation on Two-Phase Flow in Secondary Side of Steam Generator

2013 ◽  
Author(s):  
Tenglong Cong ◽  
Wenxi Tian ◽  
Guanghui Su ◽  
Suizheng Qiu
Keyword(s):  
Heat Transfer ◽  
Energy Source ◽  
Porous Media ◽  
Steam Generator ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Porous Media Model ◽  
Secondary Side

Steam generator (SG), as the primary-to-secondary heat exchanger and pressure boundary of primary loop, should be integrated and performs well in heat transfer ability. Flow characteristics of the secondary side fluid of SG are essential to analyze U-tube wastage caused by the flow-induced vibration and thermal stress. In this paper, secondary side two-phase flow was simulated based on the porous media model. Additional momentum and energy source terms were appended to the momentum and energy equations of porous media region, respectively. The additional momentum source contained the resistances of downcomer, tube bundle, support plate and separator. The additional energy source included the heat transfer from primary side to secondary side fluid. Solving the control equations by ANSYS FLUENT solver yielded the distributions of velocity, temperature, pressure, density and quality, which can be used in the analysis of flow-induced vibration and separator.

Study on Flow Induced Vibration Analysis and Evaluation for Heat Transfer Tube of Steam Generator

2018 ◽  
Author(s):  
Xuan Huang ◽  
Huan-Huan Qi ◽  
Feng-Chun Cai ◽  
Zhi-Peng Feng ◽  
Shuai Liu
Keyword(s):  
Heat Transfer ◽  
Steam Generator ◽  
Vibration Analysis ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Heat Transfer Tube ◽  
Analysis And Evaluation ◽  
Transfer Tube

The heat transfer tube of steam generator is an important part of the primary loop boundary, the integrity is crucial to the safe operation of the whole reactor system; the flow induced vibration is one of the main factors leading to the failure of heat transfer tube in steam generator. Both ASME and RG1.20 have made a clear requirement for the analysis and evaluation of the flow induced vibration of steam generator. The flow induced vibration of heat transfer tube in two-phase flow is the difficult and important content in the analysis. In this paper, the finite element model of heat transfer tube is established and the modal analysis is carried out. Then in order to evaluate the influence of two-phase flow in the secondary side and support boundary constraint, the analytical results are compared with the natural frequencies of the heat transfer tube measured in the two-phase flow test. On the basis of accurate simulation of the dynamic characteristics of heat transfer tube in two-phase flow, the paper calculate the turbulent excitation response and the fluidelastic instability ratio aiming at the main mechanism causing the flow induced vibration of heat transfer tube in two-phase flow. Firstly, the modified PSD of turbulent excitation is proposed on the foundation of root mean square displacement amplitude of heat transfer tube measured in two-phase flow test. The calculation result of the amplitude of heat transfer tube with different void fraction can envelope the test result by using the modified PSD as input, and the safety margin is reasonable. Then we also verify whether the analysis conclusion of fluidelastic instability is in agreement with the test. Finally, the analytical technique is applied to the analysis of flow induced vibration of steam generator to verify the design of structure. The paper studies on flow induced vibration analysis and evaluation a heat transfer tube of steam generator in two-phase flow. The analysis program of flow induced vibration on the basis of the test results. The investigation can be used for the risk prediction and evaluation of flow induced vibration of heat transfer tube in two-phase flow, solve the technical difficulties of flow induced vibration analysis in two-phase flow, and provide the technical support for the flow induced vibration analysis of steam generator.

Study on Flow Induced Vibration Analysis and Evaluation for Heat Transfer Tube of Steam Generator in Two Phase Flow

2018 ◽  
Author(s):  
Huang Xuan ◽  
Qi Huan-huan ◽  
Cai Feng-chun ◽  
Feng Zhi-peng ◽  
Liu Shuai ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Steam Generator ◽  
Vibration Analysis ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Heat Transfer Tube ◽  
Analysis And Evaluation ◽  
Transfer Tube

The flow induced vibration of heat transfer tube is one of the main factors leading to the failure of heat transfer tube in steam generator, the flow induced vibration of steam generator should be analyzed and evaluated in the design of steam generation. The flow induced vibration of heat transfer tube in two phase flow is the difficult and important content in the analysis. In this paper, the finite element model of heat transfer tube is established and the modal analysis is carried out. Then in order to evaluate the influence of two phase flow in the secondary side and support boundary constraint, the analytical results are compared with the natural frequency of the heat transfer tube measured in the two phase flow test. On the basis of accurate simulation of the dynamic characteristics of heat transfer tube in two phase flow, the paper calculate the turbulent excitation response and the fluid-elastic instability ratio aiming at the main mechanism causing the flow induced vibration of heat transfer tube in two phase flow. The modified PSD of turbulent excitation is proposed on the foundation of root mean square displacement amplitude of heat transfer tube measured in two phase flow test. The calculation result of the amplitude of heat transfer tube with different void fraction can envelope the test result by using the modified PSD as input, and the safety margin is reasonable. We also verify whether the analysis conclusion of fluid-elastic instability is in agreement with the test. The paper studies on flow induced vibration analysis and evaluation for heat transfer tube of steam generator in two phase flow, modifies the analysis program of flow induced vibration on the basis of the test results, the investigation can be used at the risk prediction and evaluation of flow induced vibration of heat transfer tube in two phase flow, solve the technical difficulties of flow induced vibration analysis in two phase flow, provide the technical support for the flow induced vibration analysis of steam generator in Hualong one.

Numerical Simulation of Subcooled Flow Boiling Heat Transfer in Helical Tubes

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Jong Chull Jo ◽  
Woong Sik Kim ◽  
Chang-Yong Choi ◽  
Yong Kab Lee
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Steam Generator ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Heat Transfer Analysis ◽  
Normal Operation ◽  
Phase Flow ◽  
Two Phase ◽  
Side Flow

This paper addresses the numerical simulation of two-phase flow heat transfer in the helically coiled tubes of an integral type pressurized water reactor steam generator under normal operation using a computational fluid dynamics code. The shell-side flow field where a single-phase fluid flows in the downward direction is also calculated in conjunction with the tube-side two-phase flow characteristics. For the calculation of tube-side two-phase flow, the inhomogeneous two-fluid model is used. Both the Rensselaer Polytechnic Institute wall boiling model and the bulk boiling model are implemented for the numerical simulations of boiling-induced two-phase flow in a vertical straight pipe and channel, and the computed results are compared with the available measured data. The conjugate heat transfer analysis method is employed to calculate the conduction in the tube wall with finite thickness and the convections in the internal and external fluids simultaneously so as to match the fluid-wall-fluid interface conditions properly. Both the internal and external turbulent flows are simulated using the standard k-ε model. From the results of the present numerical simulation, it is shown that the bulk boiling model can be applied to the simulation of two-phase flow in the helically coiled steam generator tubes. In addition, the present simulation method is considered to be physically plausible in the light of discussions on the computed results.

Flow-Induced Vibration Responses of U-Tube Bundle in Air-Water Flow

2007 ◽  
Author(s):  
In-Cheol Chu ◽  
Heung June Chung ◽  
Chang Hee Lee ◽  
Hyung Hyun Byun ◽  
Moo Yong Kim
Keyword(s):  
Steam Generator ◽  
Two Phase Flow ◽  
Tube Bundle ◽  
Damping Ratio ◽  
Geometrical Parameters ◽  
Phase Flow ◽  
Elastic Instability ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Vibration Responses

In the present study, a series of experiments have been performed to investigate a fluid-elastic instability of a nuclear steam generator U-tube bundle in an air-water two-phase flow condition. A total of 39 U-tubes are arranged in a rotated square array with a pitch-to-diameter ratio of 1.633. The diameter and other geometrical parameters of U-bend region are the same to those of an actual steam generator, but the vertical length of U-tubes are reduced to 2-span in contrast to 9-span of an actual steam generator. The following parameters were experimentally measured to evaluate a fluid-elastic instability of U-tube bundles in a two-phase flow: a general tube vibration response, a critical gap velocity, a damping ratio and a hydrodynamic mass. Based on the experimental measurements, the instability factor, K, of Connors’ relation was preliminary assessed with some assumptions on the velocity and density profiles of the two-phase flow.

Flow-induced vibration of nuclear steam generator U-tubes in two-phase flow

2011 ◽  
Vol 241 (5) ◽  
pp. 1508-1515 ◽  
Author(s):  
In-Cheol Chu ◽  
Heung June Chung ◽  
Seungtae Lee
Keyword(s):  
Steam Generator ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Two Phase

Numerical Simulation of Subcooled Flow Boiling Heat Transfer in Helical Tubes

2006 ◽  
Author(s):  
Jong Chull Jo ◽  
Woong Sik Kim ◽  
Chang-Yong Choi ◽  
Yong Kab Lee
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Steam Generator ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Heat Transfer Analysis ◽  
Normal Operation ◽  
Phase Flow ◽  
Two Phase ◽  
Pressurized Water

This paper addresses the numerical simulation of two phase flow heat transfer in the helically coiled tubes of an integral type pressurized water reactor steam generator under normal operation using a CFD code. The single phase flow which flow downward direction in the shell side is also calculated together. For the calculation of tube side two-phase flow the inhomogeneous two-fluid model is used. Both the RPI (Rensselaer Polytechnic Institute) wall boiling model and the bulk boiling model are implemented for the numerical simulation and the computed results are compared with the available measured data. The conjugate heat transfer analysis method is employed to calculate the conduction in the tube wall with finite thickness and the convections in the internal and external fluids simultaneously so as to match the fluid-wall-fluid interface conditions properly. Both the internal and external turbulent flows are simulated using the standard k-ε model From the results of present numerical simulation, it is shown that the bulk boiling model can be applied to the simulation of two-phase flow in the helically coiled steam generator tubes. The results also show that the present simulation method is considered to be physically plausible when the computed results are compared with available previous experimental and numerical studies.

Power Rising and Descending Transient for the OTSG of a Small PWR

2020 ◽  
Author(s):  
Baihui Jiang ◽  
Zhiwei Zhou ◽  
Zhaoyang Xia ◽  
Qian Sun
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Flow Stability ◽  
Phase Flow ◽  
Steam Generators ◽  
Two Phase ◽  
Water Reactors ◽  
Secondary Side

Abstract As key heat transfer system in small and medium size pressurized water reactors, once-through steam generators are important parts of energy exchange between primary and secondary circuits, and are very important for the design and operation of reactors. However, two-phase flow and heat transfer in once-through steam generators are very complicated. When a reactor experience power rising and descending transient, the heat removal of once-through steam generator, the flow rate, the inlet fluid temperature and outlet steam temperature will all change accordingly. Especially when a reactor is running at a low power, the flow rate of the secondary side of OTSG is extremely small and the single-phase region of the secondary side of OTSGs is also too small. The two-phase flow instability may occur, which has a serious impact on reactor operation and safety. So, a reasonable power-up and power-down transient scheme is required to ensure operational stability when starting up and shutting down a reactor. RELAP5/MOD4.0 is a commercial software developed by Innovative System Software, LCC for transient analysis of light water reactors (LWR). After years of development and improvement, RELAP5 has been a basic tool for analysis and calculation of various simulators of nuclear power plants. Scholars all over the world have carried out a large number of analysis of two-phase flow stability using RELAP5, and the results are reliable. This paper takes once through steam generators with given structural parameters as the research object, and uses RELAP5 as the calculation tool. The influencing factors of flow instability are discussed in this paper, and the operating parameters of the fluid on the primary and secondary sides are designed to satisfy the flow stability under different powers. And a set of power-up and power-down schemes for stable operation is proposed.

Sign in / Sign up

Export Citation Format

Share Document