The study is dedicated to enhancing design and computational methodologies for thermosiphon waste... more The study is dedicated to enhancing design and computational methodologies for thermosiphon waste heat boilers (WHB) within combined cycle power plants (CCPP). The optimized WHB design and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.
The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of... more The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of Thermal and Hydraulics of Leaks and Transients) system code to be applied to a passive containment cooling system of a nuclear power plant. For the model validation, INTRAVIT (Investigation of Passive Heat Transfer in a Variably Inclined Tube) test facility setup at the University of Luxembourg was used. The first part of the paper presents a review of the existing literature on evaporation models that revealed that those models significantly simplify the physical processes that occur. Next, a modified evaporation model is proposed that offers a realistic description of various evaporation processes and the start of bubble formation using a nucleation model, and a surface density calculation model is introduced that is necessary for evaporation simulation. The final part of this work explored five different system configurations to test the evaporation model: three condenser tube inclinations (5 deg, 60 deg, and 90 deg), two riser lengths (1 m and 2.5 m), and different thermal loads. They made it possible to simulate several experiments for stable and unstable natural circulation and to verify the proposed model.
The study is dedicated to enhancing design and computational methodologies for thermosiphon waste... more The study is dedicated to enhancing design and computational methodologies for thermosiphon waste heat boilers (WHB) within combined cycle power plants (CCPP). The optimized WHB design and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.
The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of... more The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of Thermal and Hydraulics of Leaks and Transients) system code to be applied to a passive containment cooling system of a nuclear power plant. For the model validation, INTRAVIT (Investigation of Passive Heat Transfer in a Variably Inclined Tube) test facility setup at the University of Luxembourg was used. The first part of the paper presents a review of the existing literature on evaporation models that revealed that those models significantly simplify the physical processes that occur. Next, a modified evaporation model is proposed that offers a realistic description of various evaporation processes and the start of bubble formation using a nucleation model, and a surface density calculation model is introduced that is necessary for evaporation simulation. The final part of this work explored five different system configurations to test the evaporation model: three condenser tube inclinations (5 deg, 60 deg, and 90 deg), two riser lengths (1 m and 2.5 m), and different thermal loads. They made it possible to simulate several experiments for stable and unstable natural circulation and to verify the proposed model.
In recent years, the expediency of obtaining fresh water directly on the vessel due to the desali... more In recent years, the expediency of obtaining fresh water directly on the vessel due to the desalination of seawater is not in doubt. Freshwater generators are installed on all types of vessels. However, desalination plants are not always selected in the best way. They are either not economical enough, and at the same time, the low-potential heat source is not fully used on the ship, or, on the contrary, are unnecessarily complicated for the sake of a small saving in fuel consumption. This is mainly explained by the lack of information on the economics of desalination in different operating conditions of the vessel and the lack of a single methodology for determining economics.
The significance of this work is justified by the lack of experimental data on the operation of t... more The significance of this work is justified by the lack of experimental data on the operation of thermosiphons as part of the waste heat boilers (WHB) with gas turbine engines (GTE), whose capacity is from 2 to 10 MW. The aim of the work was achieved by physical modeling of the heat transfer process in the thermosiphon cavity in the range of heat loads from 0.5 to 17 kW/m 2. The study of the internal temperature difference of two-phase gravity thermosiphons at thermal loads up to 17 kW/ m 2 was performed experimentally. The paper shows a scheme of the experimental research stand. The graphical dependence of the temperature difference in the thermosiphon cavity on the heat flux density is presented. The root-mean-square error of experimental results was calculated, being up to 5.7%. The significance of the obtained results lies in that the existing calculation method was improved due to the mathematical dependences obtained for calculations of the internal temperature difference, and became applicable in the calculation of heat exchangers based on two-phase thermosiphons operating in the heat load range of up to 17 kW/m 2. The experiments performed confirm the competitiveness and high thermal efficiency of the two-phase gravitational thermosiphons under the regime conditions typical for the WHB plants. This makes promising the use of the twophase gravitational thermosiphons compared to traditional coil heating surfaces.
Improving the reliability and reducing the overall dimensions of economizers of low-power boilers... more Improving the reliability and reducing the overall dimensions of economizers of low-power boilers are urgent tasks. A promising direction for solving this problem is the use of two-phase closed gravitational thermosyphons. The lack of experimental data on the thermal efficiency of thermosyphons in the operating conditions of economizers of low-power boilers determines the relevance of this work. The aim of the work is an experimental study of the thermal efficiency of thermosyphons, as well as heat transfer processes during phase transitions of a working fluid (demineralized water), under operating conditions of economizers.The thermosyphon was made of a steel pipe with an internal diameter of 0.028 m: the boiling zone length of 1.5 m and the condensationof 0.5 m. It has been established that the thermal power of the thermosyphon was varied in the range of 350...990 W with a change in air inlet temperature in the range of 190...310 °C and cooling water-of 60...100 °C. It was established that the temperature of the thermosyphon wall exceeds the dew point of the combustion products for high sulfur fuel oil by at least 5 °C. The most significant results of the work are the obtained data on the heat transfer ability of thermosyphons, as well as recommendations on the choice of dependencies for calculating the heat transfer coefficients during boiling and condensation of the working fluid. The significance of the obtained results lies in the fact that the method of thermal calculation of thermosyphon economizers was improved due to the recommended dependencies for calculating the internal thermal resistances of thermosyphons.
This study sought to optimize the steam parameters of combined-cycle power plants as a part of th... more This study sought to optimize the steam parameters of combined-cycle power plants as a part of the integration of power and gas sectors to enhance the efficiency of the energy system. The potential for decarbonization and integration with storage systems is emphasized. A specific CCPP configuration involving a UGT 6000 DP71 gas turbine is detailed. Simulation results demonstrate CCPP performance at ambient temperature range from-35 to +45 °C, showcasing power and efficiency changes.
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, Dec 15, 2023
Although existing models of natural circulation in steam boilers involve numerous simplifications... more Although existing models of natural circulation in steam boilers involve numerous simplifications, the physical processes that occur in real-time are not considered. This study sought to improve the natural circulation model in the evaporation circuit of a thermosiphon waste heat boiler using an analytical solution and numerical simulation results. A modified natural circulation model was developed using ranked variables of velocity and heat flux in the evaporator ring channels. These results were obtained in the range of heat flux densities 1.074-9.973 kW/m 2 and temperatures of the thermosiphons hot zone 477.4-487.1 K which is typical for a waste heat boiler for cogeneration power plant with gas turbine engine 6700 kW power.
The results of experimental research of the internal temperature gradient and internal thermal re... more The results of experimental research of the internal temperature gradient and internal thermal resistance of two-phase gravity thermosyphons within the range of heat loads, typical for waste heat exchangers of low-powered plants were presented
The study is dedicated to enhancing design and computational methodologies for thermosiphon waste... more The study is dedicated to enhancing design and computational methodologies for thermosiphon waste heat boilers (WHB) within combined cycle power plants (CCPP). The optimized WHB design and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.
The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of... more The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of Thermal and Hydraulics of Leaks and Transients) system code to be applied to a passive containment cooling system of a nuclear power plant. For the model validation, INTRAVIT (Investigation of Passive Heat Transfer in a Variably Inclined Tube) test facility setup at the University of Luxembourg was used. The first part of the paper presents a review of the existing literature on evaporation models that revealed that those models significantly simplify the physical processes that occur. Next, a modified evaporation model is proposed that offers a realistic description of various evaporation processes and the start of bubble formation using a nucleation model, and a surface density calculation model is introduced that is necessary for evaporation simulation. The final part of this work explored five different system configurations to test the evaporation model: three condenser tube inclinations (5 deg, 60 deg, and 90 deg), two riser lengths (1 m and 2.5 m), and different thermal loads. They made it possible to simulate several experiments for stable and unstable natural circulation and to verify the proposed model.
The study is dedicated to enhancing design and computational methodologies for thermosiphon waste... more The study is dedicated to enhancing design and computational methodologies for thermosiphon waste heat boilers (WHB) within combined cycle power plants (CCPP). The optimized WHB design and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.
The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of... more The presented work deals with the improvement of the evaporation model of the ATHLET (Analysis of Thermal and Hydraulics of Leaks and Transients) system code to be applied to a passive containment cooling system of a nuclear power plant. For the model validation, INTRAVIT (Investigation of Passive Heat Transfer in a Variably Inclined Tube) test facility setup at the University of Luxembourg was used. The first part of the paper presents a review of the existing literature on evaporation models that revealed that those models significantly simplify the physical processes that occur. Next, a modified evaporation model is proposed that offers a realistic description of various evaporation processes and the start of bubble formation using a nucleation model, and a surface density calculation model is introduced that is necessary for evaporation simulation. The final part of this work explored five different system configurations to test the evaporation model: three condenser tube inclinations (5 deg, 60 deg, and 90 deg), two riser lengths (1 m and 2.5 m), and different thermal loads. They made it possible to simulate several experiments for stable and unstable natural circulation and to verify the proposed model.
In recent years, the expediency of obtaining fresh water directly on the vessel due to the desali... more In recent years, the expediency of obtaining fresh water directly on the vessel due to the desalination of seawater is not in doubt. Freshwater generators are installed on all types of vessels. However, desalination plants are not always selected in the best way. They are either not economical enough, and at the same time, the low-potential heat source is not fully used on the ship, or, on the contrary, are unnecessarily complicated for the sake of a small saving in fuel consumption. This is mainly explained by the lack of information on the economics of desalination in different operating conditions of the vessel and the lack of a single methodology for determining economics.
The significance of this work is justified by the lack of experimental data on the operation of t... more The significance of this work is justified by the lack of experimental data on the operation of thermosiphons as part of the waste heat boilers (WHB) with gas turbine engines (GTE), whose capacity is from 2 to 10 MW. The aim of the work was achieved by physical modeling of the heat transfer process in the thermosiphon cavity in the range of heat loads from 0.5 to 17 kW/m 2. The study of the internal temperature difference of two-phase gravity thermosiphons at thermal loads up to 17 kW/ m 2 was performed experimentally. The paper shows a scheme of the experimental research stand. The graphical dependence of the temperature difference in the thermosiphon cavity on the heat flux density is presented. The root-mean-square error of experimental results was calculated, being up to 5.7%. The significance of the obtained results lies in that the existing calculation method was improved due to the mathematical dependences obtained for calculations of the internal temperature difference, and became applicable in the calculation of heat exchangers based on two-phase thermosiphons operating in the heat load range of up to 17 kW/m 2. The experiments performed confirm the competitiveness and high thermal efficiency of the two-phase gravitational thermosiphons under the regime conditions typical for the WHB plants. This makes promising the use of the twophase gravitational thermosiphons compared to traditional coil heating surfaces.
Improving the reliability and reducing the overall dimensions of economizers of low-power boilers... more Improving the reliability and reducing the overall dimensions of economizers of low-power boilers are urgent tasks. A promising direction for solving this problem is the use of two-phase closed gravitational thermosyphons. The lack of experimental data on the thermal efficiency of thermosyphons in the operating conditions of economizers of low-power boilers determines the relevance of this work. The aim of the work is an experimental study of the thermal efficiency of thermosyphons, as well as heat transfer processes during phase transitions of a working fluid (demineralized water), under operating conditions of economizers.The thermosyphon was made of a steel pipe with an internal diameter of 0.028 m: the boiling zone length of 1.5 m and the condensationof 0.5 m. It has been established that the thermal power of the thermosyphon was varied in the range of 350...990 W with a change in air inlet temperature in the range of 190...310 °C and cooling water-of 60...100 °C. It was established that the temperature of the thermosyphon wall exceeds the dew point of the combustion products for high sulfur fuel oil by at least 5 °C. The most significant results of the work are the obtained data on the heat transfer ability of thermosyphons, as well as recommendations on the choice of dependencies for calculating the heat transfer coefficients during boiling and condensation of the working fluid. The significance of the obtained results lies in the fact that the method of thermal calculation of thermosyphon economizers was improved due to the recommended dependencies for calculating the internal thermal resistances of thermosyphons.
This study sought to optimize the steam parameters of combined-cycle power plants as a part of th... more This study sought to optimize the steam parameters of combined-cycle power plants as a part of the integration of power and gas sectors to enhance the efficiency of the energy system. The potential for decarbonization and integration with storage systems is emphasized. A specific CCPP configuration involving a UGT 6000 DP71 gas turbine is detailed. Simulation results demonstrate CCPP performance at ambient temperature range from-35 to +45 °C, showcasing power and efficiency changes.
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, Dec 15, 2023
Although existing models of natural circulation in steam boilers involve numerous simplifications... more Although existing models of natural circulation in steam boilers involve numerous simplifications, the physical processes that occur in real-time are not considered. This study sought to improve the natural circulation model in the evaporation circuit of a thermosiphon waste heat boiler using an analytical solution and numerical simulation results. A modified natural circulation model was developed using ranked variables of velocity and heat flux in the evaporator ring channels. These results were obtained in the range of heat flux densities 1.074-9.973 kW/m 2 and temperatures of the thermosiphons hot zone 477.4-487.1 K which is typical for a waste heat boiler for cogeneration power plant with gas turbine engine 6700 kW power.
The results of experimental research of the internal temperature gradient and internal thermal re... more The results of experimental research of the internal temperature gradient and internal thermal resistance of two-phase gravity thermosyphons within the range of heat loads, typical for waste heat exchangers of low-powered plants were presented
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Papers by Iurii Dolganov
and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons
and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important
findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of
thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.
and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons
and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important
findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of
thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.