scholarly journals Heat Transfer Analysis of Passive Residual Heat Removal Heat Exchanger under Natural Convection Condition in Tank

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qiming Men ◽  
Xuesheng Wang ◽  
Xiang Zhou ◽  
Xiangyu Meng
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Stratification ◽  
Heat Removal ◽  
Heat Transfer Analysis ◽  
Average Error ◽  
Water Tank ◽  
Shaped Tube ◽  
Heat Transfer Calculation ◽  
Residual Heat

Aiming at the heat transfer calculation of the Passive Residual Heat Removal Heat Exchanger (PRHR HX), experiments on the heat transfer of C-shaped tube immerged in a water tank were performed. Comparisons of different correlation in literatures with the experimental data were carried out. It can be concluded that the Dittus-Boelter correlation provides a best-estimate fit with the experimental results. The average error is about 0.35%. For the tube outside, the McAdams correlations for both horizontal and vertical regions are best-estimated. The average errors are about 0.55% for horizontal region and about 3.28% for vertical region. The tank mixing characteristics were also investigated in present work. It can be concluded that the tank fluid rose gradually which leads to a thermal stratification phenomenon.

scholarly journals Heat Transfer Analysis of Passive Residual Heat Removal Heat Exchanger under Tube outside Boiling Condition

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Yanbin Liu ◽  
Xuesheng Wang ◽  
Qiming Men ◽  
Xiangyu Meng ◽  
Qing Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Transition Region ◽  
Heat Removal ◽  
Heat Transfer Analysis ◽  
Test Facility ◽  
Heating Process ◽  
Water Tank ◽  
Shaped Tube ◽  
Residual Heat

The Passive Residual Heat Removal Heat Exchanger (PRHR HX) is an important part of the Passive Residual Heat Removal System (PRHRS). The C-shaped bundle is being used in the PRHR HX. A test facility of C-shaped tube immerged in a water tank was built to research the heat transfer of the PRHR HX. Through the experiments, three regions were found within a particular period of time during the heating process in the tank: natural convection region, transition region, and saturation boiling region. For the tube outside saturation boiling, comparisons of three different correlations in literatures with the experimental data were carried out. Results show that the Rohsenow correlation provides a best-estimate fit with the experimental results. For the tube outside transition region, a formulation is put forward to reduce error based on the Rohsenow subcooled boiling correlation.

Analysis of Heat Transfer and Flow Characteristics of AP1000 Passive Residual Heat Removal Heat Exchanger

2014 ◽  
Author(s):  
Xu Xie ◽  
Changhua Nie ◽  
Li Zhan ◽  
Hua Zheng ◽  
Pengzhou Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Temperature Difference ◽  
Tube Bundle ◽  
Natural Circulation ◽  
Heat Removal ◽  
Large Temperature ◽  
Water Tank ◽  
Secondary Side ◽  
Residual Heat

In this paper, the computational fluid dynamics (CFD) method is applied to the thermal-hydraulic analysis, while the porous media model is used to simplify AP1000 passive residual heat removal heat exchanger tube. The temperature as well as flow distribution in the secondary side of the heat exchanger are obtained, aiming at analysis of natural circulation ability. It can be noted that the fluid in the secondary side of heat exchanger moves driven by the effect of thermal buoyancy, forming the natural cycle, which takes away heat in tube bundle region. The heat transfer in water tank is mainly enhanced by vortex and turbulent flow, caused by the large resistance of tube bundle region as well as large temperature difference. This phenomenon is obvious especially for the recirculation of flow near the tube bundle. The enduring change of flow rate and direction enhance the heat transfer. Besides, the big temperature difference helps to increase the driving effect of natural circulation. Consequently, the heat transfer of the tank is enhanced by above mechanism. The results of this study contribute to the capacity analysis of passive residual heat removal of natural circulation system, providing valuable information for safe operation of AP1000.

Analysis on Heat Transfer of PRHR Heat Exchanger in Tank

2017 ◽  
Author(s):  
Jiaqi Tao ◽  
Xing Jiang ◽  
Zhenqin Xiong ◽  
Hangyu Wu ◽  
Hanyang Gu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Nuclear Reactor ◽  
Heat Removal ◽  
High Water ◽  
Water Tank ◽  
Working Pressure ◽  
Residual Heat

The heat transfer performance of a small scaled passive residual heat removal (PRHR) heat exchanger is investigated by experiment. It is consisted of 42 C-shaped tubes, which is immerged in a 6-meter high water tank. The average heat flux is obtained under broad range of the working pressure and the mass flow rate of water inside the tubes by the tests. Furthermore, the distribution of the heat flux along the tube is analyzed with the assistance of empirical correlations. The heat transfer rate of the tubes predicted agrees well with the measured value, with a discrepancy less than 5%. These results are helpful in the design of PRHR heat exchanger in nuclear reactor.

Experimental Study on Natural Convection Heat Transfer Outside Tube Bundle in Space Under Low Temperature Difference

2020 ◽  
Author(s):  
Junxiu Xu ◽  
Ming Ding ◽  
Changqi Yan ◽  
Guangming Fan
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Low Temperature ◽  
Tube Bundle ◽  
Convection Heat Transfer ◽  
Heat Removal ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Reactor Pool ◽  
Residual Heat

Abstract The Passive Residual Heat Removal System (PRHRS) is very important for the safety of the heating reactor after shutdown. PRHRS is a natural circulation system driven by density difference, therefore, the heat transfer performance of the Passive Residual Heat Removal Heat Exchanger (PRHR HX) has a great impact to the heat transfer efficiency of PRHRS. However, the most research object of PRHR HX is the C-shape heat exchanger at present, which located in In-containment Refueling Water Storage Tank (IRWST). This heat exchanger is mainly used for the PRHRS of nuclear power plants. In the swimming pool-type low-temperature heating reactor (SPLTHR), the PRHR HX is placed in the reactor pool, which the pressure and temperature of the reactor pool are relatively low, and the outside heat transfer mode of tube bundle is mainly natural convection heat transfer. In this study, a miniaturized single-phase pool water cooling system was built to investigate the natural convective heat transfer coefficient of the heat exchanger under the large space and low temperature conditions. The experimental data had been compared with several correlations. The results show that the predicted value of Yang correlation is the closest to the experimental data, which the maximum deviation is about 11%.

Normal Operational State Results of Integral Pressurized Water Reactor by Using Relap5/Mod3.4

2010 ◽  
Vol 171-172 ◽  
pp. 374-378
Author(s):  
Khan Salah Ud Din ◽  
Min Jun Peng ◽  
Muhammad Zubair
Keyword(s):  
Heat Exchanger ◽  
Nuclear Power ◽  
Transient Analysis ◽  
Heat Removal ◽  
Zirconium Hydride ◽  
Water Tank ◽  
Nuclear Power Reactor ◽  
Pressurized Water ◽  
Conceptual Study ◽  
Residual Heat

In this paper, a research has been carried out on the normal operational state of IPWR by using the thermal hydraulic system code Relap5/Mod3.4.In this study the conceptual study analysis of the reactor named as Inherent Safe Uranium Zirconium Hydride Nuclear Power Reactor INSURE-100 is considered but is only based on the conceptual study so the current research focuses on the normal operational of the reactor by using the Relap5/Mod3.4 code. For this purpose, two passive safety methods have been included for the safe operation as well as for transient analysis of the reactor. In the first one, Passive Residual Heat Removal System (PRHRS) has been modeled by taking the heat exchanger out of the Reactor Pressure Vessel (RPV) in the water tank so that it can absorb core decay heat in case of transient conditions and in the second one heat exchanger is placed both in inside and outside the RPV so that there can be another way to absorb the core residual heat. Considering these concepts figured out the normal operational state of the reactor by using Relap5/Mod3.4 in comparison with the conceptual design study of the reactor under consideration and the results extracted can be a good agreement for the transient analysis of the reactor.

Thermal Hydraulics Numerical Simulation and Optimized Design of Passive Residual Heat Removal Heat Exchanger in AP1000

2013 ◽  
Author(s):  
Huining Xia ◽  
Daogang Lu ◽  
Zheng Du ◽  
Yuhao Zhang ◽  
Xiaoliang Fu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Vertical Section ◽  
Heat Removal ◽  
Transfer Effect ◽  
Optimized Design ◽  
Water Storage Tank ◽  
Tube Section ◽  
Field Distributions ◽  
Residual Heat

A model of Passive Residual Heat Removal Heat Exchanger (PRHR HX) and In Containment Refueling Water Storage Tank (IRWST) in AP1000 had been scaled by power-volume theory. FLUENT code analysis for the characteristic of thermal stratification phenomenon and natural convective of the scaled model was performed for 2000s of transients to investigate the temperature field distributions and flow field distributions in IRWST. As for the numerical experiment, the distributions had been achieved at different times. The centralized layout of PRHR HX, which looks like a circle in a section, makes the temperature of fluid outside tubes higher at the location that closer to the upper of the circle in the horizontal tube section and closer to the center of the circle in the vertical tube section, and there may appear nuclear boiling. Then temperature difference between the tube side and fluid side is smaller, causing the heat exchanger efficiency is worse at these locations. In order to improve the heat transfer effect of PRHR HX, two schemes had been proposed. First, increase horizontal section length and shorten the vertical section length. Second, Flat layout replaces centralized layout. These models were established and simulated by FLUENT. Heat transfer coefficients of “C-tubes” were comparative analyzed to study which kind of the heat transfer effect was better. It contributes to provide some references for improving the heat transfer effect of PRHR HX.

A Numerical Research on the Heat Transfer Process for a General Passive Heat Removal System

2017 ◽  
Author(s):  
Li Wei ◽  
Liu Zhuo ◽  
Guo Qiang ◽  
Yuan Yidan
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Transfer Process ◽  
Heat Removal ◽  
Heat Transfer Process ◽  
Sensitivity Analyses ◽  
Scaling Analysis ◽  
Water Tank ◽  
Heat Removal System ◽  
Removal System

A code module for simulating a general passive heat removal system composed of an elevated water tank, a heat exchanger and pipes connecting them is developed in this paper. Then, a typical heat transfer process in this heat removal system is calculated. According to the simulation results, the flash shows the most important impact of the heat transfer process for this passive heat removal system, especially the moment of the flash appearing. In order to design a scaled-down facility with the help of a scaling method to carry out experimental studies on the heat transfer process occurring in a PHRS for developing a more efficient heat removal system, all influence factors of flash should be conducted before a scaling analysis to make a good understanding for the flash. Finally, we get some qualitative conclusions based on sensitivity analyses for some influence parameters: 1) water temperature in the water tank, system flow resistance and the length of the outlet pipe should be ensured by designing according to scaling criteria strictly; 2) choosing a heat exchanger with geometric and material similarity can realize a consistency of heat transfer efficiency and 3) the liquid level in the water tank is less important.

Heat Transfer Analysis of the Passive Residual Heat Removal System in ROSA/AP600 Experiments

1998 ◽  
Vol 124 (1) ◽  
pp. 18-30 ◽  
Author(s):  
Taisuke Yonomoto ◽  
Yutaka Kukita ◽  
Richard R. Schultz
Keyword(s):  
Heat Transfer ◽  
Heat Removal ◽  
Heat Transfer Analysis ◽  
Heat Removal System ◽  
Removal System ◽  
Residual Heat
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