scholarly journals Visualization of physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB to diagnose the condition of external heat supply networks

2021 ◽  
Vol 2131 (5) ◽  
pp. 052069
Author(s):  
A Petrov ◽  
A Popov
Keyword(s):  
Mathematical Models ◽  
Heat Supply ◽  
Single Phase ◽  
Heat Supply System ◽  
External Heat ◽  
Supply Networks ◽  
Physical And Mathematical Models ◽  
Multi Phase ◽  
New Generation ◽  
Thermodynamic Processes

Abstract Nowadays, Russia has the longest heating network system in Europe (about 125 000 km in total). Given the constant growth in the volume of construction space, the length will constantly increase. Consequently, there is a request to increase the level of reliability of heat supply networks. It is possible to satisfy the request only by increasing the volume and quality of comprehensive diagnostics of heat supply networks with simultaneous reduction of time costs. This is possible only if a new generation of measurement and computing complex (MCC) is developed for the diagnosis of heat supply networks. The team of authors examines the features of the information environment in heat supply networks, separately noting the possibility of switching the flow from single-phase to multi-phase and back. The paper proposes to consider a solution to a problem that arises when trying to visualize physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB. It consists in the fact that the desired physical and mathematical model should describe the thermodynamic processes of a single-phase flow, but taking into account that this flow moves in the external heat supply network. The possibility of using the MATLAB functional environment for developing a model based on visually oriented programming is considered in detail, which allows us to lay the foundations for further forecasting the development of the heat supply system.

Optimal Expansion and Reconstruction of Heat Supply Systems

2013 ◽  
Vol 2 (4) ◽  
pp. 59-79 ◽  
Author(s):  
V. A. Stennikov ◽  
T. B. Oshchepkova ◽  
N. V. Stennikov
Keyword(s):  
Heat Supply ◽  
Optimal Allocation ◽  
Heat Supply System ◽  
Real Problem ◽  
Supply Networks ◽  
System A ◽  
Pumping Stations ◽  
Heat Supply Systems ◽  
Integrated Technique ◽  
Supply Systems

The paper addresses the issue of optimal expansion and reconstruction of heat supply systems, which includes a set of general and relatively specific problems. Therefore, a comprehensive approach to their solving is required to obtain a technically admissible and economically sound result. Solving the problem suggests search for effective directions in expansion of a system in terms of optimal allocation of new heat sources, their type, output, operating area; construction of new heat networks, their schemes and parameters; optimal detection of “bottlenecks” in the system and ways of their elimination (expansion, dismantling, replacement, strengthening of heat pipeline sections, construction of pumping stations and other components of heat supply networks). The authors present a mathematical statement of the problem, its decomposition into separate subproblems and an integrated technique to solve it. Consideration is given to a real problem solved for a real heat supply system. A set of arising problems is presented. The application of developed methodological and computational tools is shown.

Dependence of Current Harmonics of Greenhouse Irradiators on Supply Voltage

2020 ◽  
pp. 85-88 ◽  
Author(s):  
Nadezhda P. Kondratieva
Keyword(s):  
Mathematical Models ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Feasibility Studies ◽  
Power Losses ◽  
Voltage Level ◽  
Supply Networks ◽  
Current Harmonics ◽  
Cable Lines ◽  
Harmonic Composition

The article describes the results of the study concerning the effect of the voltage level on current harmonic composition in greenhouses irradiators. It is found that its change affects the level of current harmonics of all types of the studied greenhouse irradiators. With decrease of nominal supply voltage by 10 %, the total harmonic distortion THDi decreases by 9 % for emitters equipped with high pressure sodium lamps (HPSL), by 10 % for emitters with electrode-less lamps and by 3 % for LED based emitters. With increase of nominal supply voltage by 10 %, THDi increases by 23 % for lighting devices equipped with HPSL, by 10 % for irradiators with electrode-less lamps and by 3 % for LED based emitters. Therefore, changes of supply voltage cause the least effect on the level of current harmonics of LED based emitters and then the emitters with electrode-less lamps. Change of the level of supply voltage causes the greatest effect on the level of current harmonics of HPSL based irradiators. Mathematical models of dependence of THDi on the level of supply voltage for greenhouse emitters equipped with LED, electrode-less lamps and HPSL lamps were formulated. These mathematical models may be used for calculations of total current when selecting transformers and supply cable lines for greenhouse lighting devices, for design of new or reconstruction of existing irradiation systems of greenhouse facilities, and for calculation of power losses in power supply networks of greenhouse facilities during feasibility studies for energy saving and energy efficiency increasing projects.

ANALYSIS OF INTEGRATION OF SOLAR COLLECTOR SYSTEMS INTO DISTRICT HEAT SUPPLY NETWORKS

2013 ◽  
Vol 12 (10) ◽  
pp. 2041-2050 ◽  
Author(s):  
Jolanta Dvarioniene ◽  
Jurga Sinkuniene ◽  
Inga Gurauskiene ◽  
Giedrius Gecevicius ◽  
Zaneta Stasiskiene
Keyword(s):  
Solar Collector ◽  
Heat Supply ◽  
Supply Networks

scholarly journals Energy efficiency and ecological quality of buildings by process control of heat supply systems

2018 ◽  
Vol 251 ◽  
pp. 03052 ◽  
Author(s):  
Andrey Benuzh ◽  
Sergey Fedorov ◽  
Ekaterina Orenburova
Keyword(s):  
Process Control ◽  
Heat Supply ◽  
Heat Supply System ◽  
Heat Transfer Fluid ◽  
Industrial Buildings ◽  
Operation Algorithm ◽  
And Control ◽  
Supply Systems ◽  
Continuous Heat

The article presents special characteristics of mathematical modeling of the process control a resource efficient heat supply system of industrial buildings and facilities, where constant temperature maintenance is especially critical for the process. A functional diagram of the operation of the continuous heat supply process is provided. The dependence of temperature at the point of heat-transfer fluid mixing on environmental is analyzed and control system operation algorithm is proposed.

The Work Hardening of Single Phase and Multi-Phase Aluminium Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 71-78 ◽  
Author(s):  
J. David Embury ◽  
Warren J. Poole ◽  
David J. Lloyd
Keyword(s):  
Work Hardening ◽  
Aluminium Alloys ◽  
Single Phase ◽  
Dynamic Recovery ◽  
Uniform Elongation ◽  
Strengthening Mechanisms ◽  
Plastic Response ◽  
Spring Back ◽  
Hardening Process ◽  
Multi Phase

The process of work hardening in aluminum alloys is important from the viewpoint of formability and the prediction of the properties of highly deformed products. However the complexity of the strengthening mechanisms in these materials means that one must carefully consider the interaction of dislocations with the detailed elements of the microstructure and the related influence of the elements on dislocation accumulation and dynamic recovery. In addition, it is necessary to consider the influence of the work hardening process at various levels of plastic strain. This permits the possibility of designing microstructure for tailored plastic response, e.g. not simply designed for yield strength but also considering uniform elongation, spring-back, ductility etc. This presentation will explore the concept of identifying the various interactions which govern the evolution of the work hardening and their possible role in alloy design.

Investigations and designing of a geothermal heat supply system

2010 ◽  
Vol 57 (4) ◽  
pp. 341-346 ◽  
Author(s):  
V. A. Butuzov ◽  
G. V. Tomarov ◽  
E. V. Bryantseva ◽  
V. V. Butuzov
Keyword(s):  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Geothermal Heat
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