scholarly journals Thermal Stress and Deformation of Hollow Paddle-Shaft Components with Internal High Temperature Molten Salt Flow

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1557
Author(s):  
Taha Rajeh ◽  
Basher Hassan Al-Kbodi ◽  
Houlei Zhang

Excessive thermal stress and deformation are important reasons causing disservice of high temperature heat exchangers. This paper presents thermal stress and expansion analysis of single-leaf type hollow paddle-shaft components with internal high temperature molten salt flow based on three-dimensional numerical simulations. The results show that the hollow paddles enhance the heat transfer and decrease the maximum thermal stress simultaneously with the expense of a much higher pressure drop than that of solid paddles. The cumulative von Mises stress distribution curve shows that the stress distribution of the component with hollow paddles is more uniform than that with solid paddles. The radial and axial deformations do not differ much for the components with hollow and solid paddles. A larger volume of the fluid space in the hollow paddles leads to stronger heat transfer, smaller maximum thermal stress, and more uniform stress distribution. The effects of the paddle height, the diameter and number of flow holes, the molten salt flow rate, and the material-side heat transfer coefficient are identified. The advantages of hollow paddle designs in both heat transfer and thermal stress (local and overall) performance are revealed. The work in this study can provide a reference for the design and optimization of hollow paddle heat exchangers with high temperature molten salt as working fluid.

2016 ◽  
Vol 34 (Special Issue 1) ◽  
pp. S43-S50 ◽  
Author(s):  
Kai Zhang ◽  
Jiangyong Du ◽  
Xinzhi Liu ◽  
Houlei Zhang

2007 ◽  
Vol 52 (3) ◽  
pp. 618-624 ◽  
Author(s):  
Tomoaki Satoh ◽  
Kazuhisa Yuki ◽  
Shin-ya Chiba ◽  
Hidetoshi Hashizume ◽  
Akio Sagara

Author(s):  
Wen Fu ◽  
Xizhen Ma ◽  
Peiyue Li ◽  
Minghui Zhang ◽  
Sheng Li

Printed circuit heat exchangers are considered for use as the intermediate heat exchangers (IHXs) in high temperature gas-cooled reactors (HTGRs), molten salts reactors (MSRs) and other advanced reactors. A printed circuit heat exchanger (PCHE) is a highly integrated plate-type compact heat exchanger with high-temperature, high-pressure applications and high compactness. A PCHE is built based on the technology of chemical etching and diffusion bonding. A PCHE with supercritical carbon dioxide (CO2) as the working fluid was designed in this study based on the theory correlations. Three-dimensional numerical analysis was then conducted to investigate the heat transfer and pressure drop characteristics of supercritical CO2 in the designed printed circuit heat exchanger using commercial CFD code, FLUENT. The distributions of temperature and velocity through the channel were modeled. The influences of Reynolds number on heat transfer and pressure drop were analyzed. The numerical results agree well with the theory calculations.


Author(s):  
Si-Hwa Jeong ◽  
Min-Gu Won ◽  
Nam-Su Huh ◽  
Yun-Jae Kim ◽  
Young-Jin Oh ◽  
...  

In this paper, the thermal stress characteristics of the pipe-in-pipe (PIP) system under high temperature condition are analyzed. The PIP is a type of pipe applied in sodium-cooled faster reactor (SFR) and has a different geometry from a single pipe. In particular, under the high temperature condition of the SFR, the high thermal stress is generated due to the temperature gradient occurring between the inner pipe and outer pipe. To investigate the thermal stress characteristics, three cases are considered according to geometry of the support. The fully constrained support and intermediate support are considered for case 1 and 2, respectively. For case 3, both supports are applied to the actual curved pipe. The finite element (FE) analyses are performed in two steps for each case. Firstly, the heat transfer analysis is carried out considering the thermal conduction, convection and radiation conditions. From the heat transfer analysis, the temperature distribution results in the piping system are obtained. Secondly, the structural analysis is performed considering the temperature distribution results and boundary conditions. Finally, the effects of the geometric characteristics on the thermal stress in the PIP system are analyzed.


Author(s):  
Josua P. Meyer ◽  
Leon Liebenberg ◽  
Jonathan A. Olivier

Heat exchangers are usually designed in such a way that they do not operate in the transition region. This is usually due to a lack of information in this region. However, due to design constraints, energy efficiency requirements or change of operating conditions, heat exchangers are often forced to operate in this region. It is also well known that entrance disturbances influence where transition occurs. The purpose of this paper is to present experimental heat transfer and pressure drop data in the transition region for fully developed and developing flows inside smooth tubes using water as the working fluid. The use of different inlet disturbances were used to investigate its effect on transition. A tube-in-tube heat exchanger was used to perform the experiments, which ranged in Reynolds numbers from 1 000 to 20 000, with Prandtl numbers being between 4 and 6 while Grashof numbers were in the order of 105. Results showed that the type of inlet disturbance could delay transition to a Reynolds number as high as 7 000, while other inlets expedited it, confirming results of others. For heat transfer, though, it was found that transition was independent of the inlet disturbance and all commenced at the same Reynolds number, 2 000–3 000, which was attributed to secondary flow effects.


Author(s):  
Ece Özkaya ◽  
Selin Aradag ◽  
Sadik Kakac

In this study, three-dimensional computational fluid dynamics (CFD) analyses are performed to assess the thermal-hydraulic characteristics of a commercial Gasketed Plate Heat Exchangers (GPHEx) with 30 degrees of chevron angle (Plate1). The results of CFD analyses are compared with a computer program (ETU HEX) previously developed based on experimental results. Heat transfer plate is scanned using photogrammetric scan method to model GPHEx. CFD model is created as two separate flow zones, one for each of hot and cold domains with a virtual plate. Mass flow inlet and pressure outlet boundary conditions are applied. The working fluid is water. Temperature and pressure distributions are obtained for a Reynolds number range of 700–3400 and total temperature difference and pressure drop values are compared with ETU HEX. A new plate (Plate2) with corrugation pattern using smaller amplitude is designed and analyzed. The thermal properties are in good agreement with experimental data for the commercial plate. For the new plate, the decrease of the amplitude leads to a smaller enlargement factor which causes a low heat transfer rate while the pressure drop remains almost constant.


2014 ◽  
Vol 73 (2) ◽  
pp. 1519-1524 ◽  
Author(s):  
Jianfeng Lu ◽  
Shiquan He ◽  
Jing Ding ◽  
Jianping Yang ◽  
Junming Liang

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