scholarly journals The Effect Of Turbulence Models On Coolant Temperature And Velocity For The Pebble-Bed Typed High Temperature Reactor

KnE Energy ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhammad Subekti
Keyword(s):  
High Temperature ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Coolant Temperature ◽  
Face Centered Cubic ◽  
Pebble Bed ◽  
Computational Fluid Dynamics Cfd ◽  
High Temperature Reactor ◽  
The Difference ◽  
Face Centered

<p>The 3D thermal-hydraulics analysis based on Computational Fluid Dynamics (CFD) has a role to analysis more detail the reactor safety, especially for pebble-bed typed High Temperature Reactor (HTR). A realistic pebble arrangement becomes a challenge to be modeled based on the Simple Cubic (SC), Body-Centered Cubic (BCC) and Face-Centered Cubic (FCC). Furthermore, CFD calculation could utilizes laminar model as well as turbulence model such as ,  and Reynold stress model (RSM). Therefore, the objective of this reseach is to analyze the effect of turbulence model on temperature and coolant velocity distribution using FCC on pebble-bed typed HTR as well as investigation of the turbulence models. The comparison shows that all models are acceptable for HTR-10 case with the difference by the range of 0.03-0.33% for the temperature parameters, in which the minimum different is obtained by  model.</p><p> </p>

Flow Visualization of Pebble Bed HTGR

2008 ◽  
Author(s):  
Jae-Young Lee ◽  
Sa-Ya Lee
Keyword(s):  
Three Dimensional ◽  
Particle Identification ◽  
Face Centered Cubic ◽  
Mean Flow ◽  
Pebble Bed ◽  
Stagnation Points ◽  
Image Velocimetry ◽  
Flow Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
Face Centered

The nuclear core of High Temperature Gas Reactor (HTGR) with pebble bed type has been investigated intensively due to its benefits in management, but its complicated flow geometry requested the reliable analytical method. Recent studies have been made using the three dimensional computational methods but they need to be evaluated with the experimental data. Due to the complicated and narrow flow channel, the intrusive methods of flow measurement are not proper in the study. In the present study, we developed a wind tunnel for the pebble bed geometry in the structure of Face Centered Cubic (FCC) and measure the flow field using the Particle Image Velocimetry (PIV) directly. Due to the limitation of the image harnessing speed and accessibility of the light for particle identification, the system is scaled up to reduce the mean flow velocity by keeping the same Reynolds number of the HTGR. The velocity fields are successfully determined to identify the stagnation points suspected to produce hot spots on the surface of the pebble. It is expected that the present data is useful to evaluate the three dimensional Computational Fluid Dynamics (CFD) analysis. Furthermore, It would provide an insight of experimental method if the present results are compared by those of scaled down and liquid medium.

Computational Fluid Dynamics Assessment of the Local Hot Core Temperature in a Pebble-Bed Type Very High Temperature Reactor

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee
Keyword(s):  
Nusselt Number ◽  
High Temperature ◽  
Pressure Drop ◽  
Core Temperature ◽  
Normal Operation ◽  
Face Centered Cubic ◽  
Pebble Bed ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Assessment of the local hot core temperature during normal operation in a pebble-bed type very high temperature reactor has been carried out by using the computational fluid dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are simple cubic (SC), body-centered cubic, and face-centered cubic. The results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and Nusselt number. Both results showed a similar tendency that the pressure drop and the Nusselt number increases as the porosity decreases but there were large differences in their absolute values. The benchmark calculation for the pressure drop of the packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal-fluid behavior in an ordered pebble arrangement.

CFD Assessment of the Local Hot Core Temperature in a Pebble-Bed Type Very High Temperature Reactor

2008 ◽  
Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee
Keyword(s):  
High Temperature ◽  
Pressure Drop ◽  
Core Temperature ◽  
Normal Operation ◽  
Face Centered Cubic ◽  
Pebble Bed ◽  
Benchmark Calculation ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Assessment of the local hot core temperature during normal operation in a pebble-bed type of Very High Temperature Reactor (VHTR) has been carried out by using the Computational Fluid Dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are Simple Cubic (SC), Body-Centered Cubic (BCC), and Face-Centered Cubic (FCC). Results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and the Nusselt number but there were large differences between them. The benchmark calculation of a pressure drop for packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal fluid behavior.

NICROFER 5923 HMo-ALLOY 59

Alloy Digest ◽  
1993 ◽  
Vol 42 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
Face Centered Cubic ◽  
Low Carbon ◽  
High Alloy ◽  
Temperature Performance ◽  
Cubic Structure ◽  
Face Centered

Abstract NICROFER 5923 hMo, often called Alloy 59, was developed with extra low carbon and silicon contents and with a high alloy level of molybdenum to optimize its corrosion resistance. Nicrofer 5923hMo has a face-centered cubic structure. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: Ni-430. Producer or source: VDM Technologies Corporation.

Preferred core conceptual design of pebble bed advanced high temperature reactor

2021 ◽  
Vol 151 ◽  
pp. 107983
Author(s):  
Lianjie Wang ◽  
Wei Sun ◽  
Bangyang Xia ◽  
Yang Zou ◽  
Rui Yan
Keyword(s):  
High Temperature ◽  
Conceptual Design ◽  
Pebble Bed ◽  
High Temperature Reactor

The Modelling and Coupling Methodology of ANSYS CFX Using Porous Media for PB-AHTR

2013 ◽  
Author(s):  
Linsen Li ◽  
Haomin Yuan ◽  
Kan Wang
Keyword(s):  
Porous Media ◽  
Monte Carlo ◽  
Steady State ◽  
High Temperature ◽  
Monte Carlo Code ◽  
First Principle ◽  
Pebble Bed ◽  
Coupled Calculation ◽  
Ansys Cfx ◽  
High Temperature Reactor

This paper introduces a first-principle steady-state coupling methodology using the Monte Carlo Code RMC and the CFD code CFX which can be used for the analysis of small and medium reactors. The RMC code is used for neutronics calculation while CFX is used for Thermal-Hydraulics (T-H) calculation. A Pebble Bed-Advanced High Temperature Reactor (PB-AHTR) core is modeled using this method. The porous media is used in the CFX model to simulate the pebble bed structure in PB-AHTR. This research concludes that the steady-state coupled calculation using RMC and CFX is feasible and can obtain stable results within a few iterations.

Temperature Corrected Turbulence Model for High Temperature Jet Flow

2004 ◽  
Vol 126 (5) ◽  
pp. 844-850 ◽  
Author(s):  
Khaled S. Abdol-Hamid ◽  
S. Paul Pao ◽  
Steven J. Massey ◽  
Alaa Elmiligui
Keyword(s):  
High Temperature ◽  
Turbulence Model ◽  
Room Temperature ◽  
Eddy Viscosity ◽  
Mixing Layer ◽  
Supersonic Jet ◽  
Turbulence Models ◽  
Jet Flows ◽  
Viscosity Term ◽  
Mixing Layer Flows

It is well known that the two-equation turbulence models under-predict mixing in the shear layer for high temperature jet flows. These turbulence models were developed and calibrated for room temperature, low Mach number, and plane mixing layer flows. In the present study, four existing modifications to the two-equation turbulence model are implemented in PAB3D and their effect is assessed for high temperature jet flows. In addition, a new temperature gradient correction to the eddy viscosity term is tested and calibrated. The new model was found to be in the best agreement with experimental data for subsonic and supersonic jet flows at both low and high temperatures.

On the Validation of Turbulence Models for Wheel and Wheelhouse Aerodynamics

2021 ◽  
Author(s):  
Kaloki Nabutola ◽  
Sandra Boetcher
Keyword(s):  
Experimental Data ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Vehicle Body ◽  
Flow Structures ◽  
Time Resolved ◽  
Flow Control Devices ◽  
Vehicle Aerodynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Drag And Lift

Abstract Vehicle aerodynamics plays an important role in reducing fuel consumption. The underbody contributes to around 50% of the overall drag of a vehicle. As part of the underbody, the wheels and wheelhouses contribute to approximately 25-30% of the overall drag of a vehicle. As a result, wheel aerodynamics studies have been gaining popularity. However, a consensus of an appropriate turbulence model has not been reached, partially due to the lack of experiments appropriate for turbulence model validation studies for this type of flow. Seven turbulence models were used to simulate the flow within the wheelhouse of a simplified vehicle body, and results were shown to be incongruous with commonly used experimental data. The performance of each model was evaluated by comparing the aerodynamic coefficients obtained using computational fluid dynamics (CFD) to data collected from the Fabijanic wind tunnel experiments. The various turbulence models generally agreed with each other when determining average values, such a mean drag and lift coefficients, even if the particular values did not fall within the uncertainty of the experiment; however, they exhibited differences in the level of resolution in the flow structures within the wheelhouse. These flow structures are not able to be validated with currently available experimental data. Properly resolving flow structures is important when implementing flow control devices to reduce drag. Results from this study emphasize the need for spatially and time-resolved experiments, especially for validating LES and DES for flow within a wheelhouse.

Sign in / Sign up

Export Citation Format

Share Document