The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Sanja Milivojevic - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
Blazenka Maslovaric - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
Rafael Mayayescas - One of the best experts on this subject based on the ideXlab platform.
-
optimization and controllability analysis of thermally coupled reactive distillation arrangements with minimum use of Reboilers
Industrial & Engineering Chemistry Research, 2012Co-Authors: Maria Vazquezojeda, Juan Gabriel Segoviahernandez, Salvador Hernandez, Arturo Hernandezaguirre, Rafael MayayescasAbstract:The optimal design of reactive complex distillation systems is a highly nonlinear and multivariable problem, and the objective function used as optimization criterion is generally nonconvex with several local optimums and subject to several constraints. The esterification of lauric acid and methanol is explored using thermally coupled distillation sequences with side columns and with a minimum number of Reboilers. The product of the esterification can be used as biodiesel. This is a major step forward since thermally coupled reactive distillation sequences with side columns and with a minimum number of Reboilers offer significant benefits, such as the following: reductions on both capital investment and operating costs due to the absence of the Reboilers and higher conversion and selectivity since products are removed as they are produced as well as no occurrence of thermal degradation of the products due to a lower temperature profile in the column. In this work, we have studied the design of reactive di...
-
thermally coupled reactive distillation systems with minimum number of Reboilers optimization using differential evolution
2012Co-Authors: Maria Vazquezojeda, Juan Gabriel Segoviahernandez, Salvador Hernandez, Arturo Hernandezaguirre, Rafael Mayayescas, Mineral De Valenciana, Santiago TapiaAbstract:The esterification of lauric acid and methanol is explored using thermally coupled distillation sequences with side columns and with minimum number of Reboilers. The product of the esterification can be used as biodiesel. The design and optimization of reactive complex distillation systems is a highly non-linear and multivariable problem, and the objective function used as optimization criterion is generally non-convex with several local optimums and subject to several constraints. In this work, we have studied the design of reactive distillation with thermal coupling with minimum number of Reboilers, using differential evolution with restrictions coupled to AspenONE Aspen Plus. The results indicate that the energy consumption and total annual cost of the complex distillation sequence with minimum number of Reboilers are reduced significantly in comparison with conventional reactive distillation process.
Shailesh Gupta - One of the best experts on this subject based on the ideXlab platform.
-
recirculation model of kettle reboiler
International Journal of Heat and Mass Transfer, 2003Co-Authors: Shalendra Kumar, B. Mohanty, A Jain, Shailesh GuptaAbstract:Abstract The present paper deals with the simulation of a kettle reboiler. Considering rectangular tube sheet, concept of internal recirculation developed in a kettle reboiler during boiling, changes in physico-thermal property of liquid and liquid vapour mixture with temperature and pressure and using empirical correlations, a hydrodynamic model has been developed to determine pressure drop, vapour quality, recirculation rate, boiling regime, and heat transfer coefficient at various tube rows of the bundle. Results show, recirculation rate in a reboiler has been found to vary with the heat flux and pressure. Further, at a given value of heat flux and pressure vapour quality, mass flux, and heat transfer coefficient have been found to increase gradually from bottom to top tube row of the bundle.
S. C. Gupta - One of the best experts on this subject based on the ideXlab platform.
-
Recirculation model of kettle reboiler
International Journal of Heat and Mass Transfer, 2003Co-Authors: Sandeep Kumar, B. Mohanty, A Jain, S. C. GuptaAbstract:The present paper deals with the simulation of a kettle reboiler. Considering rectangular tube sheet, concept of internal recirculation developed in a kettle reboiler during boiling, changes in physico-thermal property of liquid and liquid vapour mixture with temperature and pressure and using empirical correlations, a hydrodynamic model has been developed to determine pressure drop, vapour quality, recirculation rate, boiling regime, and heat transfer coefficient at various tube rows of the bundle. Results show, recirculation rate in a reboiler has been found to vary with the heat flux and pressure. Further, at a given value of heat flux and pressure vapour quality, mass flux, and heat transfer coefficient have been found to increase gradually from bottom to top tube row of the bundle. © 2003 Elsevier Science Ltd. All rights reserved.
