scholarly journals Mathematical Models for Investigation of WWER-1000/320 Transients

2018 ◽  
pp. 18-23
Author(s):  
E. Nikulina ◽  
V. Severin ◽  
D. Lukinova
Keyword(s):  
Mathematical Models ◽  
Reactor Power ◽  
Thermal Processes ◽  
State Variables ◽  
Point Model ◽  
Fuel Loading ◽  
Neutron Kinetics ◽  
Operating Modes ◽  
Xenon Concentration ◽  
Control Rods

The paper presents mathematical models of the reactor WWER-1000/320, which are designed to investigate non-stationary operating modes of the reactor. The models in relative state variables include a point model of neutron kinetics with six groups of delayed neutrons and models of thermal processes, gradual heat generation, change in xenon concentration. The effects of reactivity on the movement of control rods and changes in reactor power, the effects of reactivity on changes in fuel and coolant temperatures, effect of change in the concentration of xenon are taken into account. The values of the constant parameters of the models are given for the start of stationary fuel loading.

scholarly journals Models and Algorithms of Adaptive Animal Flow Control in Rotary Milking Parlors

2019 ◽  
Vol 67 (6) ◽  
pp. 1465-1484
Author(s):  
Vladimir V. Kirsanov ◽  
Andrey Y. Izmaylov ◽  
Yakov P. Lobachevsky ◽  
Oksana A. Tareeva ◽  
Sergey N. Strebulyaev ◽  
...  
Keyword(s):  
Mathematical Models ◽  
High Performance ◽  
Dairy Farm ◽  
Computing System ◽  
Scientific Basis ◽  
Idle Time ◽  
Functional Connection ◽  
Operating Modes ◽  
Nizhny Novgorod Region ◽  
Physiological Characters

The study addresses the influence of milking duration of individual cows on the performance of conveyor-like rotary milking parlors and seeks to optimize their operation parameters and operating modes. The observational experiment was conducted in the Zhdanovsky Farm in Nizhny Novgorod Region, Russia. The dairy farm had a herd of 600 cows, divided into 10 groups by physiological characters and milk yield, and operated a 36 point milking parlor. Distribution of milking time of individual cows was studied using statistical analysis methods. The cyclogram of parlor operation and the functional connection of main parameters were analyzed using Maple analytical computing system, including its standard libraries and functions. The trends in idle time, which occurs due to undermilking of animals in one turn of the parlor, were studied. The idle time can result in overestimation of the number of stalls or decrease in the nameplate performance of the milking parlor by 30–40% from 120 to 93 cows per hour. Mathematical models, taking into account the influence of the milking time of individual animals (2 to 17 minutes) on the parameters of parlor operation, were developed. The algorithms of adaptive control over the rotational speed were proposed to minimize idle time in parlor operation and maintain the nameplate performance. The mathematical models, control algorithms and developed software can serves as a scientific basis for new designs of high-performance rotary milking parlors.

MODELS OF WWER-1000 NUCLEAR REACTOR WITH DIVISION INTO ZONES ON VERTICAL AXIS FOR INFORMATION TECHNOLOGY OF CONTROL

2021 ◽  
Vol 4 ◽  
pp. 105-116
Author(s):  
Valeriy Severyn ◽  
◽  
Elena Nikulina ◽  
◽  
Keyword(s):  
Information Technology ◽  
Differential Equations ◽  
Mathematical Models ◽  
Nuclear Power ◽  
Nuclear Reactor ◽  
Control Object ◽  
Vertical Axis ◽  
State Variables ◽  
Relative State ◽  
Systems Of Differential Equations

Mathematical models of the WWER-1000 nuclear power reactor have been developed with division into zones along the vertical axis in the form of nonlinear systems of differential equations with dimensionless relative state variables. Models in a given number of zones along the vertical axis represent neutron kinetics, gradual heat release, thermal processes in fuel, cladding and coolant, changes in the concentration of iodine, xenon and boron. The parameters of mathematical models have been calculated based on the design and technological parameters of the V-320 series nuclear reactor. A general model of the reactor as a control object with division into zones along the vertical axis, as well as models with control of absorbing rods and boric acid, are obtained. Integration of the obtained systems of differential equations for given initial conditions allows one to obtain changes in all state variables in the reactor zones along the vertical axis. In particular, from the change in power in the zones along the vertical axis, the axial offset is calculated as the relative value of the difference between the powers of the upper and lower halves of the reactor core. The developed reactor models with dimensionless relative state variables use a minimum number of calculations, allow calculating the change in the axial offset, and are included in the information technology for controlling the power units of nuclear power plants to optimize the maneuvering modes of the WWER-1000 V-320 series reactor.

scholarly journals Taking into Account the Operating Modes of the Steam Turbine Stage When Modeling Hydrodynamic and Thermal Processes in Non-Steam and Motor Modes

2020 ◽  
Vol 175 ◽  
pp. 492-499
Author(s):  
E.K. Arakelyan ◽  
G.A. Pikina ◽  
A.V. Andryushin ◽  
S.V. Mezin ◽  
K.A. Andryushin ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Thermal Processes ◽  
Turbine Stage ◽  
Operating Modes

scholarly journals Mathematical modeling of thermal processes during "cassette" crystallization of chalcogenides

2020 ◽  
Vol 6 (1) ◽  
pp. 9-16
Author(s):  
Anatoly I. Prostomolotov ◽  
Nataliya A. Verezub
Keyword(s):  
Heat Exchange ◽  
Mathematical Models ◽  
Crystallization Front ◽  
Reduction Rate ◽  
Exchange Model ◽  
Radiative Heat Exchange ◽  
Thermal Processes ◽  
Melt Crystallization ◽  
Heating Unit ◽  
Asymmetrical Design

A new, relatively simple and highly efficient modification of the directional melt crystallization method in the form of a multi-cassette process has been considered. This study is based on Russian Patents and technological studies conducted at National Research and Technological University MISiS. As a result, mathematical models of a multi-cassette method have been developed for 3D radiation and conduction analysis of thermal processes in the entire volume of the heating unit and 2D analysis of convection and conduction heat exchange in a separate cassette. Parameters have been calculated on the basis of these mathematical models for clarifying the effect of heating unit component arrangement and dimensions on the formation of thermal fields in cassette units, the effect of vertical homogeneity of heat supply to the cassette unit and heating power reduction rate during crystallization on the shape of the crystallization front, as well as the effect of small asymmetry in cassette design and violation of cassette bottom cooling homogeneity on convection and asymmetrical heat transfer. Application of the conductive and radiative heat exchange model to the entire heating unit has allowed us to calculate process parameters on the basis of which we have analyzed the effect of heating unit components, their arrangement and temperature on the heat exchange conditions at the cassette unit boundaries. Application of the convective and conductive model to one growth cassette has shown that asymmetrical design and boundary thermal conditions as well as unstable vertical temperature gradient lead to the formation of convection vortices and substantial crystallization front deviation from planar shape. Calculations on the basis of the convective mass exchange model have shown that an increase in the crystallization rate by one order of magnitude greatly increases the tellurium flow into the crystal thus substantially altering the melt composition in the vicinity of the crystallization front and hence serving as a potential origin of dendrite growth. The authenticity of the calculation results has been verified in a number of tests aimed at analyzing the effect of heat and mass transport on crystallization front shape for cassette cooling rates that are typical of polycrystalline bismuth telluride growth processes.

scholarly journals Mathematical models of operating modes of extractors with microwave heating

2018 ◽  
Vol 2018 (5) ◽  
pp. 183-194
Author(s):  
V. Bandura ◽  
◽  
B. Kotov ◽  
R. Kalinichenko ◽  
◽  
...  
Keyword(s):  
Mathematical Models ◽  
Microwave Heating ◽  
Operating Modes

State and Parametric Estimation of Nonlinear Systems Described by Wiener Sate-Space Mathematical Models

2015 ◽  
pp. 107-145 ◽  
Author(s):  
Houda Salhi ◽  
Samira Kamoun
Keyword(s):  
Nonlinear Systems ◽  
Mathematical Models ◽  
State Estimation ◽  
Estimation Algorithm ◽  
The State ◽  
Parametric Estimation ◽  
State Variables ◽  
Estimation Algorithms ◽  
And Performance ◽  
The Stability

This chapter deals with the description, the parametric estimation, the state estimation, and the parametric and state estimation conjointly of nonlinear systems. The focus is on the class of nonlinear systems, which are described by Wiener state-space discrete-time mathematical models. Thus, the authors develop a new recursive parametric estimation algorithm, which is based on least squares techniques. The stability conditions of the developed parametric estimation scheme are analyzed using the Lyapunov method. The state estimation problem of the considered nonlinear systems is formulated. Thus, the authors propose a recursive state estimation algorithm, which is based on Kalman Filter. A new recursive algorithm is proposed, which permits one to estimate conjointly the parameters and the state variables of nonlinear systems described by Wiener mathematical models, with unknown parameters and state variables. The efficiency and performance of the proposed recursive estimation algorithms are tested on numerical simulation examples.

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