Title
Numeričko-eksperimentalna analiza termomehaničkog stanja strukture plameno-dimnocevnih kotlova pri promenljivim režimima rada
Creator
Rajić, Milena, 1987-
CONOR:
23744615
Copyright date
2020
Object Links
Select license
Autorstvo-Nekomercijalno-Bez prerade 3.0 Srbija (CC BY-NC-ND 3.0)
License description
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Language
Serbian
Cobiss-ID
Theses Type
Doktorska disertacija
description
Datum odbrane: 24.09.2021.
Other responsibilities
Academic Expertise
Prirodno-matematičke nauke
Academic Title
-
University
Univerzitet u Nišu
Faculty
Mašinski fakultet
Group
Katedra za termotehniku, termoenergetiku i procesnu tehniku
Alternative title
Numerical-experimental analysis of thermomechanical state of the structure of fire-tube hot-water boiler under transient operating modes
Publisher
[M. N. Rajić]
Format
246, [9] listova
description
Biografija autora: list 242,
Bibliografija: list. 191-200.
description
Thermoenergetics, thermotechnique and process engineering
Abstract (en)
The subject of scientific research is hot water fire-tube boilers with a regular and screened reversing chamber. In addition to nominal operating mode, transient operating modes are analyzed, as well as one of the most important transient operating regimes – boiler start-up. The effects of various phenomena which may have impact on boiler safety, reduction of its reliability and its opearting life, are also analysed. The effects of the following phenomena are presented: deposits on fire tube and smoke pipes, thickness of the wall carring pipes of the first reflecting chamber, electrochemical corrosion, stress corrosion, fatigue and creep. Scientific methods of mathemnatical-numerical analysis with application of Ansys software package as well as experimental methods on a real object and minimized boiler model are applied in the research. Operational experiences indicate failures during operation, which represent a consequence of conditions with parameters that are higher than allowed. If such occurs, the security protection system should react in a timely manner and prevent accidents. However, emergency conditions are also possible due to fatigue of the materials of certain elements of the boiler, whose service life is shortened, due to constant exposure to high pressures and stresses. The hot water boiler structure is exposed not only to high pressures but also to high temperatures, which is why thermal stresses are dominant in those elements of the boiler with thicker walls. Thermal stresses are highest at the largest temperature gradients, which occur at variable operating modes. Therefore, the emphasis of this paper is on the variable operating modes of the hot water boiler and their impact on the structure.
Authors Key words
Vrelovodni kotao, Promenljivi režimi rada, Numerička analiza, Eksperimentalna analiza
Authors Key words
Hot water boiler, Transient operating modes, Numerical analysis, Experimental analysis
Classification
621.182:621.184.74]:519.6(043.3)
Subject
T 200
Type
Tekst
Abstract (en)
The subject of scientific research is hot water fire-tube boilers with a regular and screened reversing chamber. In addition to nominal operating mode, transient operating modes are analyzed, as well as one of the most important transient operating regimes – boiler start-up. The effects of various phenomena which may have impact on boiler safety, reduction of its reliability and its opearting life, are also analysed. The effects of the following phenomena are presented: deposits on fire tube and smoke pipes, thickness of the wall carring pipes of the first reflecting chamber, electrochemical corrosion, stress corrosion, fatigue and creep. Scientific methods of mathemnatical-numerical analysis with application of Ansys software package as well as experimental methods on a real object and minimized boiler model are applied in the research. Operational experiences indicate failures during operation, which represent a consequence of conditions with parameters that are higher than allowed. If such occurs, the security protection system should react in a timely manner and prevent accidents. However, emergency conditions are also possible due to fatigue of the materials of certain elements of the boiler, whose service life is shortened, due to constant exposure to high pressures and stresses. The hot water boiler structure is exposed not only to high pressures but also to high temperatures, which is why thermal stresses are dominant in those elements of the boiler with thicker walls. Thermal stresses are highest at the largest temperature gradients, which occur at variable operating modes. Therefore, the emphasis of this paper is on the variable operating modes of the hot water boiler and their impact on the structure.
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