DEM-CFD Study of Purge Gas Flow in Pebble Bed of WCCB for CFETR

2017 ◽  
Author(s):  
Youhua Chen ◽  
Lei Chen ◽  
Songlin Liu
Keyword(s):  
Pressure Drop ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Diameter Ratio ◽  
Pebble Bed ◽  
Ratio Requirement ◽  
Packing Factor ◽  
Test Reactor ◽  
Purge Gas ◽  
Cfd Method

As one of the breeding blanket candidates for China Fusion Engineering Test Reactor (CFETR), the water-cooled ceramic blanket (WCCB) was proposed to use mono-sized beryllium pebble bed and binary mixed Li2TiO3/Be12Ti pebble bed in order to increase the packing factor and meet the tritium breeding ratio requirement. Helium (mixed with 0.1% content of H2) is used as the purge gas to sweep tritium out when it flows through the pebble beds. Purge gas flow characteristics are of great importance to tritium recovery system design and will dominate the tritium sweep capability. In this study, DEM-CFD method was used to study the flow characteristics including porosity distribution, velocity distribution and pressure drop in the pebble beds. Mono-sized pebble bed with a packing factor of 0.61 and binary mixed pebble beds with the diameter ratio of 6:1, packing factor of 0.755, and diameter ratio of 7:1, packing factor of 0.7513 were simulated. This method can be used to study the detailed flow characteristics in pebble beds and optimize the pebble bed packing parameters to obtain an appropriate pressure drop, and could be extended to study tritium sweep capability for the design of fusion blanket.

CFD Study on the Flow Characteristics in Filleted Microchannels

2011 ◽  
Vol 103 ◽  
pp. 268-273
Author(s):  
Hong Jie Yan ◽  
Ping Zhou ◽  
Ze Lin Xu ◽  
Zhuo Chen ◽  
Jing Wen Mo
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Flow Model ◽  
Constant Width ◽  
Flow Characteristics ◽  
Flow Pressure ◽  
Cfd Method ◽  
Poiseuille Number ◽  
The Relationship ◽  
Laminar Flow Model

The flow characteristics of water in filleted microchannels were simulated based on CFD method. The flow pressure drop at different aspect ratioandRenumber were rearranged on the simulating results with laminar flow model. The results indicated that the pressure drop enlarges with the increase of in the case of the constant width of the microchannel. Within the range ofRenumber of interest, Poiseuille number of the flow is constant for differentRe, but decreases with increasing aspect ratio. An equation was fitted to describe the relationship betweenPonumber and aspect ratio, i.e. .

Numerical Simulation on the Parallel Combined Nozzles of Mini/Micro Gas Flow Standard Device

2012 ◽  
Vol 472-475 ◽  
pp. 2000-2003
Author(s):  
Jin Long Meng ◽  
Zhao Qin Yin
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Micro Gas Flow ◽  
Actual Flow Rate ◽  
Actual Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

The flow characteristics in mini/micro sonic nozzles have been studied in this paper using the computational fluid dynamics (CFD) method. The result shows that the flow rate of the parallel combined nozzles is not equal to but smaller than that of the sum of the nozzles. The reason is the each effect of the air after nozzles, which changes the flow field parameters .The more number of the parallel combined nozzles, the bigger error exits between actual flow rate and that of the sum of the nozzles. The result is consistent to the experiment. The study also shows the smaller of the nozzle’s diameter, the bigger error exits.

Computational Fluid Dynamic Analysis of Gas Flow Characteristics in a New Type of Scrubber Based on Mechanical Materials

2013 ◽  
Vol 700 ◽  
pp. 119-122
Author(s):  
Yi Gang Luan ◽  
Zheng Heng Zhao ◽  
Peng Fei Liu
Keyword(s):  
Pressure Drop ◽  
Dynamic Analysis ◽  
Computational Fluid Dynamic ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Symmetry Plane ◽  
Flow Characteristics ◽  
Wire Mesh ◽  
Computational Fluid Dynamic Analysis ◽  
New Type

In this paper, a new type of vertical scrubber is designed and a computational fluid dynamic analysis of gas flow through the device is presented. The simulation results are obtained by FLUENT 6.3. Through the two-dimension simplification of mist-mat, the resistance characteristic of the wire-mesh is gained. To simulate the gas flow of the scrubber, mist-mat is replaced by porous media. Through the analysis of simulate results, flow characteristic and pressure drop of the scrubber is obtained. Additionally, CFD analysis results show the entrance direction of the gas in vane inlet symmetry plane is benefit to avert severely velocity impulse and scrubber’s pressure drop rises with the growth of the eliminator’s velocity.

DEM-CFD simulation of purge gas flow in a solid breeder pebble bed

2016 ◽  
Vol 113 ◽  
pp. 288-292 ◽  
Author(s):  
Hao Zhang ◽  
Zhenghong Li ◽  
Haibing Guo ◽  
Minyou Ye ◽  
Hongwen Huang
Keyword(s):  
Gas Flow ◽  
Cfd Simulation ◽  
Pebble Bed ◽  
Purge Gas

Thermo-Hydraulic Analysis of the Optimized Helium Cooled Solid Breeder Blanket for CFETR

2016 ◽  
Author(s):  
Shijie Cui ◽  
Dalin Zhang ◽  
Jie Chang ◽  
Wenxi Tian ◽  
Suizheng Qiu ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Critical Conditions ◽  
Inlet Temperature ◽  
Tritium Breeding ◽  
Pebble Bed ◽  
Temperature Distributions ◽  
Neutron Multiplier ◽  
Test Reactor ◽  
Cfd Method ◽  
Solid Breeder Blanket

China Fusion Engineering Test Reactor (CFETR) is under design recently, in which a conceptual structure of the helium-cooled solid breeder blanket is proposed as one of the candidate tritium breeding blankets. In this concept, three radial arranged U-shaped breeding zones are designed and optimized for higher Tritium Breeding Ratio (TBR) and structure simplification. This blanket uses the Li4SiO4 lithium ceramic pebbles as the breeder, while beryllium pebbles as the neutron multiplier. In this paper, the thermal and fluid dynamic analyses of the optimized typical outboard blanket module are performed by CFD method, where the nuclear heating rate is obtained from the preliminary neutronics calculations. The thermal hydraulic behaviors of the first wall (FW), the temperature distributions of submodule structure material, Li4SiO4 pebble bed and Beryllium pebble bed under normal and critical conditions are calculated, respectively. The results show that the temperature on the blanket module can be effectively cooled below allowable temperature limits of the materials, even if the FW is suffering the maximum surface heat flux, which verified the reasonability of the design of the blanket cooling scheme. In addition, several parametric sensitivity studies are conducted to investigate the influences of main parameters (e.g. coolant mass flow rate, inlet temperature, pebble bed thermal conductivity and fusion power) on the temperature distributions of the blanket components.

Investigation of Pressure Drop for Fluid Flow Through Porous Media: Application to a Pebble-Bed Reactor

2010 ◽  
Author(s):  
Xiaoyu Cai ◽  
Guanghui Su ◽  
Suizheng Qiu ◽  
Wenxi Tian
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Flow Characteristics ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Flow Through Porous Media ◽  
Pebble Bed ◽  
Two Phase ◽  
Pebble Bed Reactor ◽  
Flow Through

The present studied Pebble-Bed Reactor is a light-water cooled reactor that consists of millions of Micro-Fuel Elements, and the TRISO-coated fuel particles (MFE) fill the fuel assembly disorderly and form a porous media with internal heat source. Papers on porous media continue to be published at the rate of about 150 per year and the domain of application is wide spread, ranging from chemical particle beds, mass separator units, debris beds, soil investigations, heat pipes and fluidized beds etc. In this paper, investigation is performed on the press drop under conditions of both single-phase and two-phase flow through porous media. Large number of relations are studied and the relational expressions, which generalize the available data of experiments, are suggested for pressure drop calculation in a pebble bed of spheres at random distribution. Finally, the relational expressions are applied to analyze the flow characteristics of the Pebble-Bed Reactor, such as the influence of pressure on two phase friction factor in the core etc.

Heat Transfer and Fluid Flow Characteristics of Nonboiling Two-Phase Flow in Microchannels

2011 ◽  
Vol 133 (10) ◽  
Author(s):  
Kyosung Choo ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase ◽  
Channel Diameter ◽  
Fluid Flow Characteristics

In this study, heat transfer and fluid flow characteristics of nonboiling two-phase flow in microchannels were experimentally investigated. The effects of channel diameter (140, 222, 334, and 506 μm) on the Nusselt number and the pressure drop were considered. Air and water were used as the test fluids. Results were presented for the Nusselt number and the pressure drop over a wide range of gas superficial velocity (1.24–40.1 m/s), liquid superficial velocity (0.57–2.13 m/s), and wall heat flux (0.34–0.95 MW/m2). The results showed that the Nusselt number increased with increasing gas flow rate for the large channels of 506 and 334 μm, while the Nusselt number decreased with increasing gas flow for the small channels of 222 and 140 μm. Based on these experimental results, a new correlation for the forced convection Nusselt number was developed. In addition, the two-phase friction multiplier is shown to decrease as channel diameter decreases due to the influence of viscous and surface tension forces.

Simulation and experimental analysis of purge gas flow characteristic for pebble bed

2021 ◽  
Vol 172 ◽  
pp. 112778
Author(s):  
Chirag Sedani ◽  
Maulik Panchal ◽  
Paritosh Chaudhuri
Keyword(s):  
Experimental Analysis ◽  
Gas Flow ◽  
Flow Characteristic ◽  
Pebble Bed ◽  
Purge Gas
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