The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform

Sharad Kumar Gupta - One of the best experts on this subject based on the ideXlab platform.

  • mathematical modeling of co2 separation from gaseous mixture using a hollow fiber membrane module physical mechanism and influence of partial wetting
    Journal of Membrane Science, 2015
    Co-Authors: N Goyal, Shishir Suman, Sharad Kumar Gupta
    Abstract:

    The present study describes a steady-state phenomenological model for CO2 separation via reactive absorption into aqueous Diethanolamine (DEA) solution using a micro-porous Poly-propylene (PP) Hollow-Fiber Membrane Module (HFMM). The developed model is based on the fundamental mechanisms of molecular diffusion, bulk convection and liquid-phase chemical reaction, and simultaneously accounts for the consequences of ‘partial-wetting’ phenomenon. Furthermore, a physically-consistent wetting mechanism has been formulated assuming that the membrane pores may be modeled as a bundle of straight cylindrical capillaries with distinct radii (characterized by the membrane pore-size distribution) and equal lengths, while keeping in mind the various pore-scale micro-physical phenomena. Under the simplifying parameterizations of the Finite-Volume Method (FVM), the source-code for discretized equations was compiled and implemented using C++ Language for a co-current module operation with aqueous DEA solution flowing inside the fiber-lumen and CO2–N2 gaseous mixture passing through the shell-side. A Benchmarking Analysis revealed an excellent agreement between the model predictions and the experimental data reported in open-literature, thereby validating the current model formulation, and rendering it fundamentally relevant with respect to the wetting-phenomenon. In addition, the module performance in terms of CO2 flux, Overall Mass-Transfer Coefficient (MTC), and Removal-Efficiency, has been systematically analyzed pertaining to the physical influence of other operating variables such as absorbent concentration, hydrodynamics, Pressure, temperature, and membrane characteristics. From a modeling standpoint, it may be concluded that the present model successfully captures various observations vis-a-vis the process of CO2 separation using micro-porous HFMMs, reported previously in the literature. Moreover, for a given gas-phase hydrodynamics, the current set of results suggest the existence of a unique liquid-phase hydrodynamic regime, bounded by a minimum and a maximum Permissible Pressure, under which the module can be effectively operated without any dispersive losses. Besides, the currently developed model has been demonstrated to explain the reduction in CO2 flux over time by allowing for morphological changes, including an enlargement in the average pore-size and a broadening of the pore-size distribution.

  • mathematical modeling of co2 separation from gaseous mixture using a hollow fiber membrane module physical mechanism and influence of partial wetting
    Journal of Membrane Science, 2015
    Co-Authors: N Goyal, Shishir Suman, Sharad Kumar Gupta
    Abstract:

    The present study describes a steady-state phenomenological model for CO2 separation via reactive absorption into aqueous Diethanolamine (DEA) solution using a micro-porous Poly-propylene (PP) Hollow-Fiber Membrane Module (HFMM). The developed model is based on the fundamental mechanisms of molecular diffusion, bulk convection and liquid-phase chemical reaction, and simultaneously accounts for the consequences of ‘partial-wetting’ phenomenon. Furthermore, a physically-consistent wetting mechanism has been formulated assuming that the membrane pores may be modeled as a bundle of straight cylindrical capillaries with distinct radii (characterized by the membrane pore-size distribution) and equal lengths, while keeping in mind the various pore-scale micro-physical phenomena. Under the simplifying parameterizations of the Finite-Volume Method (FVM), the source-code for discretized equations was compiled and implemented using C++ Language for a co-current module operation with aqueous DEA solution flowing inside the fiber-lumen and CO2–N2 gaseous mixture passing through the shell-side. A Benchmarking Analysis revealed an excellent agreement between the model predictions and the experimental data reported in open-literature, thereby validating the current model formulation, and rendering it fundamentally relevant with respect to the wetting-phenomenon. In addition, the module performance in terms of CO2 flux, Overall Mass-Transfer Coefficient (MTC), and Removal-Efficiency, has been systematically analyzed pertaining to the physical influence of other operating variables such as absorbent concentration, hydrodynamics, Pressure, temperature, and membrane characteristics. From a modeling standpoint, it may be concluded that the present model successfully captures various observations vis-a-vis the process of CO2 separation using micro-porous HFMMs, reported previously in the literature. Moreover, for a given gas-phase hydrodynamics, the current set of results suggest the existence of a unique liquid-phase hydrodynamic regime, bounded by a minimum and a maximum Permissible Pressure, under which the module can be effectively operated without any dispersive losses. Besides, the currently developed model has been demonstrated to explain the reduction in CO2 flux over time by allowing for morphological changes, including an enlargement in the average pore-size and a broadening of the pore-size distribution.

Palanichamy Gandhidasan - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamic analysis of a closed-cycle, solar gas-turbine plant
    Energy Conversion and Management, 1993
    Co-Authors: Palanichamy Gandhidasan
    Abstract:

    Abstract Thermodynamic analysis of a closed-cycle, Brayton gas-turbine plant with a heat exchanger powered by the sun has been studied. A Brayton cycle is simpler than a Rankine cycle and has an advantage in places where water is scarce and expensive. A simple expression is derived for calculating the efficiency of the cycle in terms of the compression Pressure ratio, the Pressure loss coefficient and the ratio of the lower to higher temperature in the cycle with the efficiency of various components. The maximum Permissible Pressure loss coefficient has also been calculated.

A. B. Samsonov - One of the best experts on this subject based on the ideXlab platform.

  • Studying regularities of functioning of passive droplet-sheet collectors in radiator systems under open space conditions
    Thermal Engineering, 2014
    Co-Authors: A. A. Koroteev, E. S. Popushina, A. B. Samsonov
    Abstract:

    A constituent part of frameless devices for rejecting low-potential heat in cycles of new-generation space power plants is a collector of dispersed droplet sheet. Regularities of functioning of passive collectors characterized by the absence of moving parts are studied. Theoretical fundamentals and methods for mathematical and program implementation are developed for the problems of studying motion of films of liquid ultrahigh-vacuum working fluids in space over planar surfaces under conditions of localized mass injection. The physical regularities are revealed that characterize the flow evolution, the outer surface shape of the film, the dependence of its thickness on the initial velocity of motion, coolant temperature, and geometry of the collecting device. The relationships for shape and size of the droplet collector surface are found and parameters of the supporting film of the coolant are defined, whose application may ensure an overlap of collector throat by the film and the achievement of minimum Permissible Pressure of the recirculating coolant.

N Goyal - One of the best experts on this subject based on the ideXlab platform.

  • mathematical modeling of co2 separation from gaseous mixture using a hollow fiber membrane module physical mechanism and influence of partial wetting
    Journal of Membrane Science, 2015
    Co-Authors: N Goyal, Shishir Suman, Sharad Kumar Gupta
    Abstract:

    The present study describes a steady-state phenomenological model for CO2 separation via reactive absorption into aqueous Diethanolamine (DEA) solution using a micro-porous Poly-propylene (PP) Hollow-Fiber Membrane Module (HFMM). The developed model is based on the fundamental mechanisms of molecular diffusion, bulk convection and liquid-phase chemical reaction, and simultaneously accounts for the consequences of ‘partial-wetting’ phenomenon. Furthermore, a physically-consistent wetting mechanism has been formulated assuming that the membrane pores may be modeled as a bundle of straight cylindrical capillaries with distinct radii (characterized by the membrane pore-size distribution) and equal lengths, while keeping in mind the various pore-scale micro-physical phenomena. Under the simplifying parameterizations of the Finite-Volume Method (FVM), the source-code for discretized equations was compiled and implemented using C++ Language for a co-current module operation with aqueous DEA solution flowing inside the fiber-lumen and CO2–N2 gaseous mixture passing through the shell-side. A Benchmarking Analysis revealed an excellent agreement between the model predictions and the experimental data reported in open-literature, thereby validating the current model formulation, and rendering it fundamentally relevant with respect to the wetting-phenomenon. In addition, the module performance in terms of CO2 flux, Overall Mass-Transfer Coefficient (MTC), and Removal-Efficiency, has been systematically analyzed pertaining to the physical influence of other operating variables such as absorbent concentration, hydrodynamics, Pressure, temperature, and membrane characteristics. From a modeling standpoint, it may be concluded that the present model successfully captures various observations vis-a-vis the process of CO2 separation using micro-porous HFMMs, reported previously in the literature. Moreover, for a given gas-phase hydrodynamics, the current set of results suggest the existence of a unique liquid-phase hydrodynamic regime, bounded by a minimum and a maximum Permissible Pressure, under which the module can be effectively operated without any dispersive losses. Besides, the currently developed model has been demonstrated to explain the reduction in CO2 flux over time by allowing for morphological changes, including an enlargement in the average pore-size and a broadening of the pore-size distribution.

  • mathematical modeling of co2 separation from gaseous mixture using a hollow fiber membrane module physical mechanism and influence of partial wetting
    Journal of Membrane Science, 2015
    Co-Authors: N Goyal, Shishir Suman, Sharad Kumar Gupta
    Abstract:

    The present study describes a steady-state phenomenological model for CO2 separation via reactive absorption into aqueous Diethanolamine (DEA) solution using a micro-porous Poly-propylene (PP) Hollow-Fiber Membrane Module (HFMM). The developed model is based on the fundamental mechanisms of molecular diffusion, bulk convection and liquid-phase chemical reaction, and simultaneously accounts for the consequences of ‘partial-wetting’ phenomenon. Furthermore, a physically-consistent wetting mechanism has been formulated assuming that the membrane pores may be modeled as a bundle of straight cylindrical capillaries with distinct radii (characterized by the membrane pore-size distribution) and equal lengths, while keeping in mind the various pore-scale micro-physical phenomena. Under the simplifying parameterizations of the Finite-Volume Method (FVM), the source-code for discretized equations was compiled and implemented using C++ Language for a co-current module operation with aqueous DEA solution flowing inside the fiber-lumen and CO2–N2 gaseous mixture passing through the shell-side. A Benchmarking Analysis revealed an excellent agreement between the model predictions and the experimental data reported in open-literature, thereby validating the current model formulation, and rendering it fundamentally relevant with respect to the wetting-phenomenon. In addition, the module performance in terms of CO2 flux, Overall Mass-Transfer Coefficient (MTC), and Removal-Efficiency, has been systematically analyzed pertaining to the physical influence of other operating variables such as absorbent concentration, hydrodynamics, Pressure, temperature, and membrane characteristics. From a modeling standpoint, it may be concluded that the present model successfully captures various observations vis-a-vis the process of CO2 separation using micro-porous HFMMs, reported previously in the literature. Moreover, for a given gas-phase hydrodynamics, the current set of results suggest the existence of a unique liquid-phase hydrodynamic regime, bounded by a minimum and a maximum Permissible Pressure, under which the module can be effectively operated without any dispersive losses. Besides, the currently developed model has been demonstrated to explain the reduction in CO2 flux over time by allowing for morphological changes, including an enlargement in the average pore-size and a broadening of the pore-size distribution.

S Schindler - One of the best experts on this subject based on the ideXlab platform.

  • on the design of the tubesheet and the tubesheet to shell junction of a fixed tubesheet heat exchanger
    International Journal of Pressure Vessels and Piping, 2006
    Co-Authors: K Behseta, S Schindler
    Abstract:

    Abstract For the (mechanical) design of an existing fixed tubesheet heat exchanger, a C2-Hydrogenation reactor in a petrochemical plant, various code solutions are compared with each other and with a Finite Element solution based on the Direct Route in Design by Analysis (EN 13445-3, Annex B). The codes and standards used in the investigation are ASME Section VIII, Division 1 and EN 13445-3, Clause 13 and Annex J. The ASME VIII/2 and TEMA codes are not appropriate for this design. The ASME VIII/1 and EN 13445-3 Clause 13 approaches are similar. Differences in maximum Permissible Pressures result partly from different nominal design stresses. The modern EN 13445-3 Annex J approach, being based on limit analysis theory, leads to very different, much more efficient results. The Direct Route in Design by Analysis confirms the EN 13445-3 Annex J results, but gives, at the same time, clear insight into the behaviour of the whole structure and the various maximum Permissible Pressure limiting details.

  • on the design of the tubesheet and the tubesheet to shell junction of a fixed tubesheet heat exchanger
    ASME 2006 International Mechanical Engineering Congress and Exposition, 2006
    Co-Authors: K Behseta, S Schindler
    Abstract:

    On the hand of the (mechanical) design of an existing, very large, extreme fixed tubesheet heat exchanger, a C2-Hydrogenation reactor in a petrochemical plant, various code solutions are compared, with each other and with a Finite Element solution based on the Direct Route in Design by Analysis (EN 13445-3, Annex B). The codes and standards used in the investigation are ASME Section VIII, Division 1 (and 2), (TEMA), and EN 13445-3, Clause 13 and Annex J. ASME VIII/2, and TEMA are not appropriate for this design. ASME VII/1 and EN 13445-3 Clause 13 approaches are similar. Differences in maximum Permissible Pressures result partly from different nominal design stresses. The modern EN 13445-3 Annex J approach, being based on limit analysis theory, leads to very different, much more efficient results. The Direct Route in Design by Analysis confirms the EN 13445-3 Annex J results, but gives, at the same time, clear insight into the behaviour of the whole structure and the various maximum Permissible Pressure limiting details.© 2006 ASME