scholarly journals Modeling of heat transfer in a fuel pellet based on uranium dioxide and ceramics (beryllium oxide)

2021 ◽  
Vol 318 (3) ◽  
pp. 81-89
Author(s):  
U.K. Zhapbasbayev ◽  
◽  
A.D. Kudaibergen ◽  
◽  
◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Uranium Dioxide ◽  
Calculated Data ◽  
Beryllium Oxide ◽  
Fuel Pellet ◽  
Comsol Multiphysics ◽  
Model Calculations ◽  
Composite Fuel ◽  
Fuel Elements

The results of heat transfer mathematical model calculations in the “UO2-BeO” pellet are presented. The fuel pellet consists of uranium dioxide (UO2) and beryllium oxide (BeO) ceramics. Modeling of heat transfer was carried out by a system of generalized heat conduction equations with variable thermophysical properties. The calculated data of the temperature field in the fuel pellet were obtained using the COMSOL Multiphysics software code. The results of temperature calculations were compared with the data of other authors. The agreement of the calculated data shows the mathematical model and the COMSOL Multiphysics code algorithms correctness. Various arrangements of beryllium oxide ceramics BeO in a fuel pellet are considered. The arrangement of the BeO ceramics in the centre of the fuel pellet showed a noticeable decrease in temperature in the energy release zone. Calculations have shown that the composite fuel “UO2-BeO” is the most effective for regulating the thermal regime of fuel elements.

Heat transfer in LMFBR fuel elements Part I: Effects of fuel pellet displacement

1974 ◽  
Vol 26 (3) ◽  
pp. 376-387 ◽  
Author(s):  
P.R. Barrett
Keyword(s):  
Heat Transfer ◽  
Fuel Pellet ◽  
Fuel Elements

THERMAL RESISTANCE OF POWER SEMICONDUCTOR MODULES OF SOLDERED CONSTRUCTION

2020 ◽  
Vol 5 ◽  
pp. 122-130
Author(s):  
S.I. MATYUKHIN ◽  
D.O. MALYI ◽  
A.S. VISHNYAKOV ◽  
E.Yu. ORLOV ◽  
V.I. KAZAKOV
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Computer Simulation ◽  
Thermal Resistance ◽  
Comsol Multiphysics ◽  
Power Semiconductor ◽  
Transfer Processes ◽  
Main Effect

The heat transfer processes in power semiconductor modules of soldered construction are studied using the methods of computer simulation in Comsol Multiphysics software. The problem of the thermal resistance of such modules is solved. The factors showing the main effect on the thermal resistance of the modules are studied. A mathematical model allowing engineering calculations of this resistance is developed.

scholarly journals Adaptation of a Mathematical Model of Generalized Heat Exchange in Furnaces

2020 ◽  
Vol 20 (4) ◽  
pp. 12-22
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Gas Flow ◽  
Calculated Data ◽  
Combustion Products ◽  
Steam Boiler ◽  
Gas Temperature ◽  
Condi Tions ◽  
Proposed Model ◽  
The Mathematical Model

Consideration of the scheme of flows of combustion products in furnaces and flow chambers of combus-tion within the framework of the heat transfer paradigm made it possible to determine the ratio of the genera-lized mechanisms of heat transfer – convection and radiation. The transition from uniform distribution of gas flow velocity to uneven distribution in furnaces with a geometrically peculiar fence has been implemented. This made it possible to take into account the use of recirculation gases, dual-light shades, changes in the shape and size of the cross-section of the furnace, and installation of shade surfaces in a furnace. The condi-tions for the correctness of the mathematical model are considered, and the eigenvalues of the boundary value problem under conditions of an asymmetric temperature field and the function of the gas temperature changing along the height of the furnace are obtained. A comparative analysis of the nature of the change in gas temperature with height according to the proposed model with the calculation for a steam boiler with a capacity of 950 t/h according to the standard method showed a satisfactory agreement of the calculated data with an accuracy of +4.87 %.

Out-of-Pile Properties Investigation of UO2-BeO Fuel Pellet

2017 ◽  
Author(s):  
Jiwei Li ◽  
Yang Ding ◽  
Wentao Liu ◽  
Guangwen Bi ◽  
Ruirui Zhao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Uranium Dioxide ◽  
Nuclear Power ◽  
Power Plants ◽  
Elasticity Modulus ◽  
Coefficient Of Thermal Expansion ◽  
Continuous Phase ◽  
Fuel Pellet ◽  
Composite Fuel

In order to increasing the thermal conductivity of fuel pellet used in nuclear power plants, a UO2-BeO composite fuel was developed. The fuel pellets with different beryllia addition were manufactured by sintering and the physical properties were tested and compared with uranium dioxide fuel. The metallograph show that the continuous phase of beryllia was formed. The results show that the thermal conductivity was obviously larger and the elasticity modulus and the coefficient of thermal expansion were a little smaller than uranium dioxide. The thermal conductivity and the elasticity modulus were increased and the coefficient of thermal expansion was decreased by increasing the ratio of beryllia contents.

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