Defense of the dissertation of Kurmanova Dinara Esentayevna for the degree of Doctor of Philosophy (PhD) in the educational program «8D06105 - Mathematical and Computer Modeling»
L.N. Gumilyov Eurasian National University, a dissertation defense for the degree of Doctor of Philosophy (PhD) by Kurmanova Dinara Esentayevna on the topic «Numerical modeling of hydrodynamics and heat exchange during the flow of petroleum products in channels of various shapes» in the educational program «8D06105 – Mathematical and Computer Modeling».
The dissertation was carried out at the Department of «Mathematical and computer modeling» of L.N. Gumilyov Eurasian National University.
The language of defense is kazakh
Official reviewers:
Temirbekov Nurlan Mukhanovich – Doctor of Physical and Mathematical Sciences, academician, vice-president of the National Engineering Academy of the Republic of Kazakhstan (Almaty, Republic of Kazakhstan);
Shakenov Kanat Kozhakhmetovich – Doctor of Physical and Mathematical Sciences, Professor of the Department of Computational Sciences and Statistics of Al-Farabi Kazakh National University (Almaty, Republic of Kazakhstan).
Temporary members of the Dissertation Council:
Ashirbaev Nurgali Kudiyarovich – Doctor of Physical and Mathematical Sciences, Professor of the Department of Mathematics, M.Auezov South Kazakhstan University (Shymkent, Republic of Kazakhstan);
Mukhambetzhanov Saltanbek Talapedenovich - doctor of Physical and Mathematical Sciences, Chief Researcher, "Institute of Mechanics and Mechanical Engineering named after Academician U.A. Dzholdasbekov" of the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Almaty, Republic of Kazakhstan);
Nusupbekov Bekbolat Rakhishevich – Candidate of Technical Sciences, Professor, Member of the Management Board – Acting Vice-Rector for Academic Affairs of Karaganda Technical University named after Abylkas Saginov (Karaganda, Republic of Kazakhstan).
Scientific consultants:
Jaichibekov Nurbolat Zhumabekovich – Doctor of Physical and Mathematical Sciences, Professor of the Department of Mechanics at L.N. Gumilyov ENU (Astana, Republic of Kazakhstan);
Karpenko Anton Gennadyevich – Candidate of Physical and Mathematical Sciences, Associate Professor at St. Petersburg State University (Saint Petersburg, Russian Federation).
The defense will take place on December 20, 2024, at 02:00 PM in the Dissertation Council for the training direction «8D061 – Information and communication technologies» in the educational program «8D06105 – Mathematical and Computer Modeling» of L.N. Gumilyov Eurasian National University. The defense meeting is planned to be held offline and online.
Link: http://surl.li/txspoq
Address: Astana, st. Kazhymukan, 13, auditorium No. 205 of educational building No. 3.
Abstract (English): Within the framework of the dissertation work, mathematical models of hydrodynamic and thermal processes are developed on the basis of a multiscale approach and computational algorithms are implemented for numerical modeling of nonstationary spatial flows of a viscous incompressible liquid described by the Navier-Stokes equations and arising in modern HE designs (heat exchangers) used in the oil and gas industry. Within the framework of the developed models, the possible transition of the laminar flow regime to the turbulent and rheological models of petroleum products is taken into account. The developed tools for numerical modeling and control of hydrodynamic and heat exchange processes are the basis for optimizing HE used in the oil and gas industry. At the same time, one of the key elements is to ensure the joint resolution of the flow structure within the framework of models of processes of various physical nature. The relevance of the study is due to the need to solve a number of problems related to measures to intensify heat transfer between heat carriers. Mathematical modeling and calculation of the dynamics and heat exchange of heat exchangers of various types is an urgent direction for the design of a heat exchanger for very viscous media with highly variable viscosity (fuel oil, oil) used in the petrochemical industry and effectiveness the geometric dimensions of heat exchangers. The purpose of the dissertation is the development, implementation and application of mathematical models related to the control and optimization of heat exchangers (HE); reducing the viscosity of oil by effectively heating it and determining the effective length of the HE. The main objectives of the study are: selection of ratios (formulas) of the dependence of liquid viscosity on temperature necessary to describe the movement of a particular petroleum product through a pipeline; numerical modeling of hydrodynamics and heat transfer of heat carriers in the HE; numerical calculation in the Matlab application software package to determine the distribution of mass average temperatures and the Reynolds number along the length of the HE for a «pipe-in-pipe» type heat exchanger with a smooth surface; verification of calculation results with data obtained in the Ansys Fluent software environment for the case of piecewise-constant viscosity; numerical studies of hydrodynamics and heat transfer for heat exchangers of various types, including helicoid (with high velocity of passage of the medium); consideration of laminar-turbulent transition to a helicoid-shaped HE and consideration of the real rheological properties of petroleum products. The object of research is heat exchangers with channels of various shapes. The theoretical significance consists in clarifying the mathematical model of hydrodynamics and heat transfer in relation to the dynamics of heat carriers in heat exchangers, as well as monitoring the heat transfer process in various types of HE. The practical significance lies in the application of mathematical modeling methods for the development, manufacture and operation of heat exchangers: the results obtained using mathematical modeling and numerical experiments are a source of information used by the developer when designing new equipment, technologies, evaluating the quality and efficiency of the created installations. The novelty of the study consists in: - taking into account the variable viscosity of oil when calculating the heat exchanger, namely the strong dependence of the viscosity of oil on its temperature;- the definition of laminar-turbulent variable flow mode in the calculation of the heat exchanger; - in determining the effective length of the heat exchanger; an increase in oil temperature due to the use of a helicoid heat exchanger. Provisions for protection: 1. The method of calculating the heat exchanger with a strong dependence of the viscosity of petroleum products on temperature; 2. The results of numerical calculation of hydrodynamics and heat exchange processes in HE with smooth tube surfaces obtained by computational fluid dynamics methods using a turbulence model taking into account the laminar-turbulent transition. 3. Results of numerical calculation of hydrodynamics and heat exchange processes in HE with surfaces of tubes having coils (helicoid shape of HE). The author's personal contribution consists in creating program codes in the Matlab package and performing calculations in the Ansys Fluent software package and graphical representation of calculation results. Development of numerical modeling of hydrodynamics and heat transfer, determination of calculation parameters. Preparation of scientific articles and abstracts. Approbation of the work. The main results of the work in the dissertation were reported and discussed at: 1) The XVII International Scientific Conference of Students and Young Scientists "ǴYLYM JÁNE BILIM – 2022" (L.N.Gumilyov ENU, Astana, 2022, - April 12). 2) The International Scientific Conference dedicated to the 80th anniversary of Professor T.G.Mustafin. Actual problems of mathematics, mechanics and computer science. ((E.A.Buketov KarSU, Karaganda, 2022, - September 8). 3) XVIII International Scientific Conference of Students and Young Scientists "ǴYLYM JÁNE BILIM – 2023" (L.N.Gumilyov ENU, Astana, 2023, - April 12). 4) VII World Congress of Turkish World Mathematicians (TWIMS Congress-2023) (International Kazakh-Turkish University named after H.A.Yasavi, Turkestan, 2023, September 21-23). 5) The XIX International Scientific Conference of Students and Young Scientists "ǴYLYM JÁNE BILIM – 2024" (L.N.Gumilyov ENU, Astana, 2024, - April 12). 6) International Scientific Conference "Modern Problems of Mathematics and Computer Science" dedicated to the 10th anniversary of the Department of Mathematical and Computer Modeling (L.N.Gumilyov ENU, Astana, 2024, May 2-3). 7) 9th International Symposium on Advances in Computational Heat Transfer, CHT-24. (Istanbul, Turkey, 2024,-26-30 May). Publications. 13 papers have been published in collaboration with scientific consultants, of which -2 papers are included in the scientific citation index in the Scopus database, with percentiles 55 and 15, 4 articles are in journals from the list of recommended by the Committee for the Quality Assurance in the Field of Science and Higher Education of the Ministry of Science and Higher Education of the Republic of Kazakhstan, 7 publications are in Collections of Materials of international conferences. Based on Scopus: 1.Modelling and Simulation of Heat Exchanger with Strong Dependence of Oil Viscosity on Temperature//Fluids. –2023. –8(95). –P.1-18. https://doi.org/10.3390/fluids8030095 (percentile 55). 2. Математическое моделирование теплообменного аппарата с учетом сильной зависимости вязкости нефти от температуры//Научно-технический вестник информационных технологий, механики и оптики (ИТМО). –2023. –Т.23,№4. –C.820-827. (DOI 10.17586/2226-1494-2023-23-4-820-827) (percentile 15). In journals from the list of recommended by the Committee for the Quality Assurance in the Field of Science and Higher Education of the Ministry of Science and Higher Education of the Republic of Kazakhstan: 1. Численный расчет гидродинамики теплоносителей с учетом зависимости вязкости от температуры. Вестник ЕНУ им. Л.Н. Гумилева. Серия Математика. Компьютерные науки. Механика. 2022. –Том 141,№4, - С.28-41. DOI: https://doi.org/10.32523/2616-7182/bulmathenu.2022/4.2. 2. Numerical modeling and calculation of heat transfer between heat carriers in heat exchangers. Вестник Карагандинского университета. Серия «Физика», - 2023, № 1(109), - С.59-70. DOI 10.31489/2023PH1/59-70. 3.Численное моделирование параметров теплоносителей в теплообменниках геликоидной формы. Вестник ЕНУ им. Л.Н. Гумилева. Серия Математика. Компьютерные науки. Механика. -2024.- Том 146. №1. –С.17-25. DOI: https://doi.org/10.32523/2616-7182/bulmathenu.2024/1.2. 4. Mathematical model and numerical calculation of the movement of oil products in helicoidal heat exchangers. Вестник Карагандинского университета. Серия «Физика», - 2024, № 2(114). –С.72-79. In the conference materials: 1.Распределение температуры теплоносителей вдоль теплообменного аппарата//Сборник материалов XVII международной научной конференции студентов и молодых ученых «ǴYLYM JÁNE BILIM-2022». – Астана,2022: стр.1603-1607. 2. Моделирование и расчет динамики жидкостей в теплообменных аппаратах//Актуальные задачи математики, механики и информатики. Материалы Международной научной конференции, посвященной 80-летию профессора Т.Г.Мустафина. – Караганда,2022: стр.238-240. 3. Численный расчет температуры нефти на выходе из теплообменника геликоидной формы//Сборник материалов XVIII международной научной конференции студентов и молодых ученых «ǴYLYM JÁNE BILIM-2023». – Астана,2023: стр.1603-1607. 4. Numerical calculation of the parameters of heat carriers in helicoid heat exchangers//VII World Congress of Turkic World Mathematicians (TWIMS Congress-2023). – Туркестан,2023:стр.480. 5. Жылу алмастырғыштың тиімді ұзындығын түтіктен шығатын жылу тасымалдағыштың температурасы бойынша анықтау// Сборник материалов XIX международной научной конференции студентов и молодых ученых «ǴYLYM JÁNE BILIM-2024». – Астана,2024 стр.1917-1920. 6.Определение эффективной длины теплообменника по температуре теплоносителя на выходе из трубки//Математикалық және компьютерлік модельдеу кафедрасының 10 жылдығына арналған «Математика және компьютерлік ғылымдардың заманауи мәселелері» атты Халықаралық ғылыми конференция. –Астана,2024:стр.196-199. 7.Control of heat transfer characteristics in helicoidal heat exchangers with strong dependence of oil viscosity on temperature. 9th International Symposium on Advances in Computational Heat Transfer, CHT-24.- Istanbul, 2024:стр.94. The structure of the dissertation. The dissertation work consists of an introduction, three chapters, a conclusion, a list of references and an Appendix, set out on 73 pages, including 39 figures and 4 tables. The introduction provides a justification for the relevance of the work, the goals and objectives of the research, the main theoretical and practical significance, the novelty of the research and summarizes the content of the dissertation by chapters. The first chapter is an overview part, the classification of heat exchangers is given. An overview and analysis of the work of foreign scientists on the calculations of heat exchangers of various types is given. Numerical modeling of hydrodynamics and heat transfer of heat carriers in HE is considered. The dependence of the viscosity of petroleum products on the temperature required to describe the movement of a particular petroleum product through a pipeline is investigated. The method of calculating a heat exchanger with a strong dependence of the viscosity of petroleum products on temperature is considered. The second chapter presents methods of computational fluid dynamics (CFD) in the Ansys Fluent software package. The problem statement for calculating a pipe-in-pipe heat exchanger of a direct-flow type is considered, as well as the results of numerical calculation of the heat exchanger. The third chapter provides a numerical simulation of heat exchange processes in a helicoid heat exchanger. The paper presents the results of calculations of the oil temperature field depending on various hydrodynamic parameters. In conclusion, the desired values of the effective length of the pipe and the temperature of the hot coolant at the outlet of the pipe were obtained. It is revealed that with variable viscosity of oil, the transition from the laminar flow regime to the turbulent one is manifested, while the analytical calculation method for constant viscosity does not take this effect into account. The results obtained show that the model, taking into account the dependence of oil viscosity on temperature, leads to data underestimated by about 19.3% along the length of the heat exchanger compared with constant viscosity calculations.Studies have shown that the value of the average mass temperature of oil at the outlet of the tube in a helicoid heat exchanger is higher compared to a heat exchanger with smooth tubes, where the maximum relative deviation is approximately 9.5%. The appendices provide a numerical calculation of the heat exchanger (at constant and variable viscosity), developed in the Matlab R2018b program, and a diploma and certificate presented at international conferences. The author expresses to sincere gratitude to the scientific supervisor, Doctor of Physical and Mathematical Sciences, Professor N.J.Jaichibekov and foreign consultant, Candidate of Physical and Mathematical Sciences, associate Professor A.G.Karpenko.
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