The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sanja Milivojevic - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of two dimensional kettle reboiler shell side Thermal Hydraulics with swell level and liquid mass inventory prediction
International Journal of Heat and Mass Transfer, 2014Co-Authors: Blazenka Maslovaric, Vladimir Stevanović, Sanja MilivojevicAbstract:Abstract Simulation and analyses of two-phase flows across tube bundles is important for design and safety analyses of various types of steam generators and kettle reboilers. The information about the shell side Thermal–Hydraulics in this Thermal equipment should include the liquid and vapour two-phase flow velocity fields, the void fraction distribution, as well as the swell level position and the liquid mass inventory. The two-fluid model of boiling two-phase flow around tubes in the bundle is applied for the simulation of the kettle reboiler shell side Thermal–Hydraulics. The tube bundle is modelled as a porous medium. Transfer processes at the vapour–liquid interfaces and on the tube walls are predicted with closure laws. The model is numerically solved by the “in-house” CFD code. The applied modelling method is validated against measured data of pressure drops in refrigerant R113 and n-pentane two-phase flows across tube rows in the bundle of a thin slice kettle reboiler, which are available in the open literature. The swell level position on the shell side is calculated solely by solving of the two-phase flow governing equations and with the application of an appropriate closure law for the vapour–liquid drag force, which enables the prediction of the liquid separation due to gravity from the upward flowing two-phase mixture. This is an improvement on the Thermal–hydraulic modelling and numerical simulation of the kettle reboiler since the previous numerical simulations from the open literature have been performed with a priori specified swell level position and arbitrary boundary conditions for the velocity (or pressure) and void fraction boundary conditions at the swell level. The prediction of the swell level position also enables the calculation of the liquid mass inventory on the shell side, which gives insight into the kettle reboiler operating conditions and is crucial for the reliable prediction of the tube bundle dry-out during incidents of liquid feeding stoppage. There is a one-to-one correspondence between the liquid mass inventory and the swell level position. The presented simulation method enables iterative prediction of the liquid mass inventory for the specified swell level position and vice versa. In addition, the correlations for the liquid–vapour interfacial drag coefficient, which have shown previously fairly good predictions in cases of water–steam and water–air two-phase flows, are extended for the general application to other fluids.
Vladimir Stevanović - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of two dimensional kettle reboiler shell side Thermal Hydraulics with swell level and liquid mass inventory prediction
International Journal of Heat and Mass Transfer, 2014Co-Authors: Blazenka Maslovaric, Vladimir Stevanović, Sanja MilivojevicAbstract:Abstract Simulation and analyses of two-phase flows across tube bundles is important for design and safety analyses of various types of steam generators and kettle reboilers. The information about the shell side Thermal–Hydraulics in this Thermal equipment should include the liquid and vapour two-phase flow velocity fields, the void fraction distribution, as well as the swell level position and the liquid mass inventory. The two-fluid model of boiling two-phase flow around tubes in the bundle is applied for the simulation of the kettle reboiler shell side Thermal–Hydraulics. The tube bundle is modelled as a porous medium. Transfer processes at the vapour–liquid interfaces and on the tube walls are predicted with closure laws. The model is numerically solved by the “in-house” CFD code. The applied modelling method is validated against measured data of pressure drops in refrigerant R113 and n-pentane two-phase flows across tube rows in the bundle of a thin slice kettle reboiler, which are available in the open literature. The swell level position on the shell side is calculated solely by solving of the two-phase flow governing equations and with the application of an appropriate closure law for the vapour–liquid drag force, which enables the prediction of the liquid separation due to gravity from the upward flowing two-phase mixture. This is an improvement on the Thermal–hydraulic modelling and numerical simulation of the kettle reboiler since the previous numerical simulations from the open literature have been performed with a priori specified swell level position and arbitrary boundary conditions for the velocity (or pressure) and void fraction boundary conditions at the swell level. The prediction of the swell level position also enables the calculation of the liquid mass inventory on the shell side, which gives insight into the kettle reboiler operating conditions and is crucial for the reliable prediction of the tube bundle dry-out during incidents of liquid feeding stoppage. There is a one-to-one correspondence between the liquid mass inventory and the swell level position. The presented simulation method enables iterative prediction of the liquid mass inventory for the specified swell level position and vice versa. In addition, the correlations for the liquid–vapour interfacial drag coefficient, which have shown previously fairly good predictions in cases of water–steam and water–air two-phase flows, are extended for the general application to other fluids.
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a two dimensional model of the kettle reboiler shell side Thermal Hydraulics
International Journal of Heat and Mass Transfer, 2006Co-Authors: Milada Pezo, Vladimir Stevanović, Zarko StevanovicAbstract:Abstract A two-dimensional two-fluid numerical model is developed for the prediction of two-phase flow Thermal-Hydraulics on the shell side of the kettle reboiler. The two-phase flow around tubes in the bundle is modeled with the porous media approach. A closure law for the vapour–liquid interfacial friction is based on modified pipe two-phase flow correlations. The tube bundle flow resistance is calculated by applying to each phase stream the correlations for the pressure drop in a single phase flow across tube bundles and by taking into account the separate contribution of each phase to the total pressure drop. Physically based boundary conditions for the velocity field at the two-phase mixture swell level are stated. The system of governing equations is solved numerically with the finite volume approach for two-phase flow built in the commercial computer program. Simulations are performed for available conditions of performed physical experiments. In comparison to the previous kettle reboiler two-dimensional modeling approaches, here presented model is original regarding the applied closure laws for the interfacial friction and bundle flow resistance, as well as applied boundary conditions for the modeling of two-phase mixture free surface. Also, regarding the previous published results, here obtained numerical results are compared with the available measured data of void fraction within the tube bundle and acceptable agreement is shown.
Zarko Stevanovic - One of the best experts on this subject based on the ideXlab platform.
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a two dimensional model of the kettle reboiler shell side Thermal Hydraulics
International Journal of Heat and Mass Transfer, 2006Co-Authors: Milada Pezo, Vladimir Stevanović, Zarko StevanovicAbstract:Abstract A two-dimensional two-fluid numerical model is developed for the prediction of two-phase flow Thermal-Hydraulics on the shell side of the kettle reboiler. The two-phase flow around tubes in the bundle is modeled with the porous media approach. A closure law for the vapour–liquid interfacial friction is based on modified pipe two-phase flow correlations. The tube bundle flow resistance is calculated by applying to each phase stream the correlations for the pressure drop in a single phase flow across tube bundles and by taking into account the separate contribution of each phase to the total pressure drop. Physically based boundary conditions for the velocity field at the two-phase mixture swell level are stated. The system of governing equations is solved numerically with the finite volume approach for two-phase flow built in the commercial computer program. Simulations are performed for available conditions of performed physical experiments. In comparison to the previous kettle reboiler two-dimensional modeling approaches, here presented model is original regarding the applied closure laws for the interfacial friction and bundle flow resistance, as well as applied boundary conditions for the modeling of two-phase mixture free surface. Also, regarding the previous published results, here obtained numerical results are compared with the available measured data of void fraction within the tube bundle and acceptable agreement is shown.
Blazenka Maslovaric - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of two dimensional kettle reboiler shell side Thermal Hydraulics with swell level and liquid mass inventory prediction
International Journal of Heat and Mass Transfer, 2014Co-Authors: Blazenka Maslovaric, Vladimir Stevanović, Sanja MilivojevicAbstract:Abstract Simulation and analyses of two-phase flows across tube bundles is important for design and safety analyses of various types of steam generators and kettle reboilers. The information about the shell side Thermal–Hydraulics in this Thermal equipment should include the liquid and vapour two-phase flow velocity fields, the void fraction distribution, as well as the swell level position and the liquid mass inventory. The two-fluid model of boiling two-phase flow around tubes in the bundle is applied for the simulation of the kettle reboiler shell side Thermal–Hydraulics. The tube bundle is modelled as a porous medium. Transfer processes at the vapour–liquid interfaces and on the tube walls are predicted with closure laws. The model is numerically solved by the “in-house” CFD code. The applied modelling method is validated against measured data of pressure drops in refrigerant R113 and n-pentane two-phase flows across tube rows in the bundle of a thin slice kettle reboiler, which are available in the open literature. The swell level position on the shell side is calculated solely by solving of the two-phase flow governing equations and with the application of an appropriate closure law for the vapour–liquid drag force, which enables the prediction of the liquid separation due to gravity from the upward flowing two-phase mixture. This is an improvement on the Thermal–hydraulic modelling and numerical simulation of the kettle reboiler since the previous numerical simulations from the open literature have been performed with a priori specified swell level position and arbitrary boundary conditions for the velocity (or pressure) and void fraction boundary conditions at the swell level. The prediction of the swell level position also enables the calculation of the liquid mass inventory on the shell side, which gives insight into the kettle reboiler operating conditions and is crucial for the reliable prediction of the tube bundle dry-out during incidents of liquid feeding stoppage. There is a one-to-one correspondence between the liquid mass inventory and the swell level position. The presented simulation method enables iterative prediction of the liquid mass inventory for the specified swell level position and vice versa. In addition, the correlations for the liquid–vapour interfacial drag coefficient, which have shown previously fairly good predictions in cases of water–steam and water–air two-phase flows, are extended for the general application to other fluids.
Milada Pezo - One of the best experts on this subject based on the ideXlab platform.
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a two dimensional model of the kettle reboiler shell side Thermal Hydraulics
International Journal of Heat and Mass Transfer, 2006Co-Authors: Milada Pezo, Vladimir Stevanović, Zarko StevanovicAbstract:Abstract A two-dimensional two-fluid numerical model is developed for the prediction of two-phase flow Thermal-Hydraulics on the shell side of the kettle reboiler. The two-phase flow around tubes in the bundle is modeled with the porous media approach. A closure law for the vapour–liquid interfacial friction is based on modified pipe two-phase flow correlations. The tube bundle flow resistance is calculated by applying to each phase stream the correlations for the pressure drop in a single phase flow across tube bundles and by taking into account the separate contribution of each phase to the total pressure drop. Physically based boundary conditions for the velocity field at the two-phase mixture swell level are stated. The system of governing equations is solved numerically with the finite volume approach for two-phase flow built in the commercial computer program. Simulations are performed for available conditions of performed physical experiments. In comparison to the previous kettle reboiler two-dimensional modeling approaches, here presented model is original regarding the applied closure laws for the interfacial friction and bundle flow resistance, as well as applied boundary conditions for the modeling of two-phase mixture free surface. Also, regarding the previous published results, here obtained numerical results are compared with the available measured data of void fraction within the tube bundle and acceptable agreement is shown.
