scholarly journals Matrix Method for Modelling of Multicomponent and Multistream Energy Systems and Installations of Thermal Power Plants

2021 ◽  
pp. 59-67
Author(s):  
Alexey Barochkin ◽  
Keyword(s):  
Phase Transition ◽  
Mathematical Model ◽  
Heat Exchange ◽  
Steam Turbine ◽  
Arbitrary Number ◽  
Thermal Power ◽  
Energy Systems ◽  
Input And Output ◽  
Multi Stage ◽  
Mass Flows

The aim of this work is to increase the operational efficiency of the multicomponent multithreaded power units and systems of the TPP using modeling, calculation and optimization. The goal is achieved by solving the following tasks: development of the tasks’ classification system and a unified methodology for the mathematical description of energy formation and mass flows’ processes in multicomponent and multithreaded power units of the TPP; development of a model of a steam turbine power unit; development of a model of heat and mass transfer processes in multi-stage multistream multiphase systems. The most significant results obtained were: the developed unified methodology for the matrix description of the processes of energy and mass flows’ formation in multicomponent multistream energy systems of the TPP. Within the framework of the proposed methodology, a model of a steam turbine power was developed; model solutions were obtained and analyzed in order to calculate the energy characteristics of a heating turbine unit, the reliability and validity of the proposed approach was shown, a mathematical model of multistream multi-stage heat exchange systems were developed. The significance of the results obtained consisted in the development of a simple but informative mathematical model of a thermal power plant turbine generator and a model of multistream multi-stage heat exchange systems, each stage of which can have an arbitrary number of input and output flows with a possible phase transition in heat carriers.ave an arbitrary number of input and output flows with a possible phase transition in heat carriers.

scholarly journals Development of evolutionary search algorithms with binary choice relations when making decisions for pellet tubular heaters

2021 ◽  
Vol 3 (8(111)) ◽  
pp. 50-59
Author(s):  
Vyacheslav Irodov ◽  
Maksym Shaptala ◽  
Kostiantyn Dudkin ◽  
Daria Shaptala ◽  
Halyna Prokofieva
Keyword(s):  
Mathematical Model ◽  
Heat Exchange ◽  
Thermal Power ◽  
Operating Mode ◽  
Experimental Results ◽  
Practical Significance ◽  
Selection Function ◽  
Tubular Heat Exchanger ◽  
Parameter Values ◽  
Exchange Unit

A study was carried out and the optimization process was carried out for one of the types of equipment for autonomous heat supply using renewable resources – a tubular pellet heater. The research is expedient, since there is no mathematical model of the unit operation for the pellet combustion unit, there is only a set of experimental results indicating the inconsistency of the criteria presented to it. As a result of the research, new algorithms have been obtained: firstly, an algorithm for selecting (multi-criteria optimization) the operating mode of the unit for burning pellets of tubular heaters, and secondly, algorithms for choosing, according to several criteria, the parameters of the heat exchange unit of a tubular heater with a screen. A set of algorithms for multicriteria optimization with binary selection ratios has been developed for tubular pellet heaters in full, including a pellet combustion unit and a heat exchange unit. Selection functions have been defined for a pellet combustion unit using dimensionless complexes based on experimental results. For a block of a tubular heat exchanger with a screen, a selection function is built taking into account the criteria of functioning and a mathematical model of the heater in the form of a system of nonlinear ordinary differential equations. The practical significance of the algorithm for selecting the operating mode for the pellet combustion unit lies in the possibility of obtaining the most preferable (optimal, taking into account many criteria) parameters in the entire range of permissible parameters, and not only among the experiments carried out. The practical significance of optimization algorithms for a heat exchange unit lies in the ability to select specific parameter values during design – the thermal power of the heater, air flow, the length of the tubular part and the screen, their diameters, taking into account several selection criteria.

scholarly journals COMPARISON OF ENERGY FLOW STREAM AND ISENTROPIC METHOD FOR STEAM TURBINE ENERGY ANALYSIS

2019 ◽  
Vol 59 (2) ◽  
pp. 109-125 ◽  
Author(s):  
Sebastijan Blažević ◽  
Vedran Mrzljak ◽  
Nikola Anđelić ◽  
Zlatan Car
Keyword(s):  
Steam Turbine ◽  
Energy Flow ◽  
Energy Analysis ◽  
Thermal Power ◽  
Steam Turbines ◽  
Water Steam ◽  
Input And Output ◽  
Pressure Steam ◽  
Different Sources ◽  
Flow Stream

In this paper, a comparison of two different methods for a steam turbine energy analysis is presented. A high-pressure steam turbine from a supercritical thermal power plant (HPT) was analysed at three different turbine loads using the energy flow stream (EFS) method and isentropic (IS) method. The EFS method is based on steam turbine input and output energy flow streams and on the real steam turbine produced power. The method is highly dependable on the steam mass flow rate lost through the turbine gland seals. The IS method is based on a comparison of turbine steam expansion processes. Observed energy analysis methods cannot be directly compared because they are based on different sources of steam turbine energy losses, so, an overall steam turbine energy analysis is presented. Unlike most steam turbines from the literature, the analysed HPT did not have the highest overall energy efficiency at a full load due to exceeding the water/steam critical pressure at the turbine inlet during such operation.

The effect of pressure on the compressibility of aluminum alloys

2020 ◽  
pp. 102-107
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Liquid Metal ◽  
Control Systems ◽  
Physical And Mechanical Properties ◽  
Reliable Data ◽  
Output Process ◽  
Automated Control ◽  
Input And Output ◽  
Crystallization Under Pressure

To obtain reliable data on the properties of liquid metal and create automated control systems, the technological process of molding with crystallization under pressure is studied. A mathematical model of the input and output process parameters is developed. It is established that the compressibility of the melt can represent the main controlled parameter influencing on the physical-mechanical properties of the final products. The obtained castings using this technology are not inferior in their physical and mechanical properties to those produced by forging or stamping.

Adaptation of Algorithms for Diagnostics of Steam Turbine Unit Equipment to Specific Conditions at Thermal Power Stations

2020 ◽  
Vol 67 (11) ◽  
pp. 800-804
Author(s):  
K. E. Aronson ◽  
B. E. Murmansky ◽  
V. B. Novoselov ◽  
Yu. M. Brodov ◽  
A. Yu. Sosnovsky ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Turbine Unit ◽  
Thermal Power ◽  
Steam Turbine Unit ◽  
Power Stations ◽  
Thermal Power Stations

Supercritical Carbon Dioxide Brayton Cycles Driven by Solar Thermal Power Tower System

2015 ◽  
Vol 1116 ◽  
pp. 94-129 ◽  
Author(s):  
Maimoon Atif ◽  
Fahad A. Al-Sulaiman
Keyword(s):  
Carbon Dioxide ◽  
Mathematical Model ◽  
Power Systems ◽  
Solar Power ◽  
Current Model ◽  
Thermal Power ◽  
Solar Thermal ◽  
Solar Thermal Power ◽  
Thermal Energy Storage Systems ◽  
Tower System

This chapter starts with a background about concentrating solar power systems and thermal energy storage systems and then a detailed literature review about concentrated solar power systems and supercritical Brayton carbon dioxide cycles. Next, a mathematical model was developed and presented which generates and optimizes a heliostat field effectively. This model was developed to demonstrate the optimization of a heliostat field using differential evolution, which is an evolutionary algorithm. The current model illustrates how to employ the developed model and its advantages. The optimization process calculates the optical performance parameters at every step of the optimization considering all the heliostats; thus yields accurate results as discussed in this chapter. On the other hand, complete mathematical model of supercritical CO2Brayton cycles when integrated with solar thermal power tower system was presented and discussed.

A Ternary, Two-Phase, Mathematical Model of Oil Recovery With Surfactant Systems

1984 ◽  
Vol 24 (06) ◽  
pp. 606-616 ◽  
Author(s):  
Charles P. Thomas ◽  
Paul D. Fleming ◽  
William K. Winter
Keyword(s):  
Mathematical Model ◽  
Oil Recovery ◽  
Arbitrary Number ◽  
The Other ◽  
Phase System ◽  
Chemical Flooding ◽  
Two Phase ◽  
Oil Displacement ◽  
Surfactant Systems ◽  
And Diffusion

Abstract A mathematical model describing one-dimensional (1D), isothermal flow of a ternary, two-phase surfactant system in isotropic porous media is presented along with numerical solutions of special cases. These solutions exhibit oil recovery profiles similar to those observed in laboratory tests of oil displacement by surfactant systems in cores. The model includes the effects of surfactant transfer between aqueous and hydrocarbon phases and both reversible and irreversible surfactant adsorption by the porous medium. The effects of capillary pressure and diffusion are ignored, however. The model is based on relative permeability concepts and employs a family of relative permeability curves that incorporate the effects of surfactant concentration on interfacial tension (IFT), the viscosity of the phases, and the volumetric flow rate. A numerical procedure was developed that results in two finite difference equations that are accurate to second order in the timestep size and first order in the spacestep size and allows explicit calculation of phase saturations and surfactant concentrations as a function of space and time variables. Numerical dispersion (truncation error) present in the two equations tends to mimic the neglected present in the two equations tends to mimic the neglected effects of capillary pressure and diffusion. The effective diffusion constants associated with this effect are proportional to the spacestep size. proportional to the spacestep size. Introduction In a previous paper we presented a system of differential equations that can be used to model oil recovery by chemical flooding. The general system allows for an arbitrary number of components as well as an arbitrary number of phases in an isothermal system. For a binary, two-phase system, the equations reduced to those of the Buckley-Leverett theory under the usual assumptions of incompressibility and each phase containing only a single component, as well as in the more general case where both phases have significant concentrations of both components, but the phases are incompressible and the concentration in one phase is a very weak function of the pressure of the other phase at a given temperature. pressure of the other phase at a given temperature. For a ternary, two-phase system a set of three differential equations was obtained. These equations are applicable to chemical flooding with surfactant, polymer, etc. In this paper, we present a numerical solution to these equations paper, we present a numerical solution to these equations for I D flow in the absence of gravity. Our purpose is to develop a model that includes the physical phenomena influencing oil displacement by surfactant systems and bridges the gap between laboratory displacement tests and reservoir simulation. It also should be of value in defining experiments to elucidate the mechanisms involved in oil displacement by surfactant systems and ultimately reduce the number of experiments necessary to optimize a given surfactant system.

MATHEMATICAL MODEL AND EXPERIMENTAL ESTIMATION OF THERMAL PROCESSES IN HEATING MODULE AS A PART OF STEAM ABLATION DEVICE FOR VARICOSE VEINS TREATMENT

2021 ◽  
pp. 117-125
Author(s):  
Дина Владимировна Кривоносова ◽  
Евгений Сергеевич Ермолаев
Keyword(s):  
Mathematical Model ◽  
Varicose Veins ◽  
Thermal Power ◽  
Thermal Characteristics ◽  
Steam Injection ◽  
Heating Element ◽  
Vein Wall ◽  
Tissue Heating ◽  
Comparison Of The Results ◽  
The Mathematical Model

На сегодняшний день в России для лечения варикозного расширения вен часто проводятся малоинвазивные операции методами радиочастотной или лазерной облитерации, при этом метод паровой облитерации при лечении варикозной болезни не применяется совсем. Однако метод паровой облитерации обладает существенными преимуществами: малый объём и биоинертность рабочей среды - водяного пара, его невысокая температура - 120 °С, исключающая вероятность образования нагара и перфорации венозной стенки. Целью данной работы является разработка математической модели для расчёта тепловых характеристик блока нагревания, входящего в устройство для лечения варикозной болезни методом паровой облитерации. Модель описывает теплообменные процессы в гидравлической трубке блока нагревания и может быть полезна при расчёте размеров нагревательного элемента, обеспечивающих нагрев и парообразование определённой порции воды. С целью верификации математической модели результаты моделирования были сопоставлены с экспериментальными данными. Была проведена серия экспериментов, в ходе которых были получены значения энергии, содержащейся в одной инжекции пара, и объём воды в одной инжекции, а также оценена фактическая тепловая мощность нагревателя. Сравнение результатов имитационного моделирования и значения фактической тепловой мощности пара, полученной экспериментальным путем, показала работоспособность математической модели. Разработанная математическая модель позволяет подбирать геометрические параметры нагревательного элемента в зависимости от требуемой тепловой мощности, которая должна быть обеспечена блоком нагревания, а также варьировать параметры нагревательного элемента для разной степени нагрева тканей Today in Russia minimally invasive varicose veins treatment is often performed using radiofrequency or laser ablation, while the method of steam ablation is not used at all. However, the steam ablation method has significant advantages: a small volume and biological inertness of the working substance - sterile water vapor, its low temperature - 120 °C, excluding the carbon deposits and perforation of the vein wall. The purpose of this work is to develop a mathematical model for calculating the thermal characteristics of the heating module as a part of the device for varicose veins treatment using steam ablation. The model describes heat exchange processes in the hydraulic circuit of the heating module and can be applied to calculate the dimensions of the heating module which provides heating and vaporization of a certain portion of water. In order to verify the mathematical model, the simulation results were compared with experimental data. A series of experiments were carried out in which the energy contained in one steam injection and the volume of water in one injection were estimated, as well as the actual thermal power of the heating module. Comparison of the results of simulation and the value of the actual thermal power of steam obtained experimentally showed the efficiency of the mathematical model. The proposed mathematical model allows to select the geometric parameters of the heating element depending on the required thermal power, which must be provided by the heating module, and also to vary the parameters of the heating element for different degrees of tissue heating

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