The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Petr Stehlík - One of the best experts on this subject based on the ideXlab platform.
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Conventional versus specific types of heat exchangers in the case of polluted flue gas as the Process Fluid – A review
Applied Thermal Engineering, 2011Co-Authors: Petr StehlíkAbstract:Abstract The present contribution shows certain practical aspects of selection and design of heat exchangers for industrial applications where polluted flue gas (off-gas) represents one Process Fluid. One of the key factors in designing heat exchangers for these applications is the primary selection of a suitable type. The presently available possibilities and methodologies of efficient heat exchanging device selection and supporting software do not allow covering all the needs of related industries. A concrete example of an industrial Process furnace is used to demonstrate the issues of “compactness and enhancement vs. reliability” for various temperature levels of high temperature applications. Attention is also given to the specific area of fouling of the heat exchanging surfaces by flue gas. In high temperature applications, it is necessary to pay special attention to all phases of a solution. Heat integration of devices into the plant system and its possibilities are presented. The irreplaceable role of modelling and optimization on the design of heat exchangers and its design details is emphasized which may significantly contribute to final product quality. An important role in high temperature applications is also played by CFD simulations.
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conventional versus specific types of heat exchangers in the case of polluted flue gas as the Process Fluid a review
Applied Thermal Engineering, 2011Co-Authors: Petr StehlíkAbstract:Abstract The present contribution shows certain practical aspects of selection and design of heat exchangers for industrial applications where polluted flue gas (off-gas) represents one Process Fluid. One of the key factors in designing heat exchangers for these applications is the primary selection of a suitable type. The presently available possibilities and methodologies of efficient heat exchanging device selection and supporting software do not allow covering all the needs of related industries. A concrete example of an industrial Process furnace is used to demonstrate the issues of “compactness and enhancement vs. reliability” for various temperature levels of high temperature applications. Attention is also given to the specific area of fouling of the heat exchanging surfaces by flue gas. In high temperature applications, it is necessary to pay special attention to all phases of a solution. Heat integration of devices into the plant system and its possibilities are presented. The irreplaceable role of modelling and optimization on the design of heat exchangers and its design details is emphasized which may significantly contribute to final product quality. An important role in high temperature applications is also played by CFD simulations.
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Conventional versus Specific Types of Heat Exchangers in the Case of Polluted Flue Gas as the Process Fluid - A Review
Applied Thermal Engineering, 2010Co-Authors: Petr StehlíkAbstract:The present contribution shows certain practical aspects of selection and design of heat exchangers for industrial applications where polluted flue gas (off-gas) represents one Process Fluid.
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Heat Exchangers as Equipment and Integrated Items in Waste and Biomass Processing
Heat Transfer Engineering, 2007Co-Authors: Petr StehlíkAbstract:Heat recovery systems play an important role in waste to energy and biomass Processing. An efficient approach that follows a recommended hierarchy in design, Process as a whole (e.g., incineration) → subsystem of the Process (e.g., heat recovery system) → equipment (e.g., air pre-heater), is shown. Important factors have to be taken into consideration in Processes for incineration (combustion of biomass), especially available energy, specific features of hot Process Fluid (flue gas), type of waste/biomass, fouling, and environmental impact. A combination of intuitive design, know-how, and a sophisticated approach based on up-to-date computational tools is shown. Some novel types of heat exchangers (e.g., air preheaters for high- and low-temperature applications, heat recovery steam generators and/or heaters, and those for specific applications) that can be substituted for conventional ones are presented. An improved or even optimum design of heat exchangers requires computational support in the following ...
Luis San Andrés - One of the best experts on this subject based on the ideXlab platform.
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Bulk-Flow Analysis of Hybrid Thrust Bearings for Process Fluid Applications
Journal of Tribology, 1999Co-Authors: Luis San AndrésAbstract:Advanced cryogenic Fluid turbopumps are very compact, operate at extremely high shaft speeds, and require hybrid (hydrostatic/hydrodynamic) radial and thrust Fluid film bearings for accurate rotor positioning. Sound design and reliable operation of Fluid film thrust bearings also allows for unshrouded impellers with a significant increase in the turbopump mechanical efficiency. A bulk-flow analysis for prediction of the static load performance and dynamic force coefficients of high speed, angled injection orifice-compensated, hybrid (hydrostatic/hydrodynamic) thrust bearings is presented. The model accounts for the bulk-flow mass, momentum and thermal energy transport, and includes flow turbulence and Fluid inertia (advection and centrifugal) effects on the bearing film lands and recesses. The performance of a refrigerant hybrid thrust bearing for an oil-free air conditioning equipment is evaluated at two operating speeds and pressure differentials. The computed results are presented in dimensionless form to evidence consistent trends in the bearing performance characteristics. As the applied axial load increases, the bearing film thickness and flow rate decrease while the recess pressure increases. The axial stiffness coefficient shows a maximum for a certain intermediate load while the damping coefficient steadily increases with load. The computed results show the significance of centrifugal Fluid inertia at low recess pressures (i.e. low loads) and high rotational speeds, and which can lead to film starvation at the bearing inner radius and subambient pressures just downstream of the bearing recess edge.
Atsushi Tsutsumi - One of the best experts on this subject based on the ideXlab platform.
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Theoretical and Experimental Investigation on the Energy Consumption of Self-heat Recuperation Using Magnetocaloric Effect
Chemical engineering transactions, 2014Co-Authors: Cal E, Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:The minimum energy consumption needed for heat circulation is derived from the exergy destruction due to heat exchange in terms of temperature-entropy diagram. The obtained value is compared with the numerical energy consumption when magnetocaloric effect is applied to self-heat recuperation technology. Furthermore, a magnetocaloric heat circulator has newly been constructed and its energy consumption has been measured. It is explained by the temperature-entropy diagram, that the minimum energy consumption needed for heat circulation is proportional to the minimum temperature difference needed for heat exchange. In a magnetocaloric heat circulator, the heat transfer between the Process Fluid and the working material is direct, thus leading to small temperature difference during heat exchange and small input work required for heat circulation.
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Self-heat Recuperative Heat Circulator with Thermoelectric Device☆
Energy Procedia, 2014Co-Authors: Renaldo N. Rasfuldi, Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:Abstract Self-heat recuperation (SHR) technology has been proven to reduce exergy loss in different Process systems, which lead to large energy savings due to its non-combustion Process. The purpose of this research is to develop a novel self-heat recuperative heat circulation system using thermoelectric (TE) device as a heat circulator for non-gaseous systems. Most research involving TE coolers is related to maximizing the temperature difference (ΔT) of a device, whereas in self-heat recuperative heat circulator, a large ΔT is not required, but only a minimum temperature difference between the surfaces of the TE device and Process Fluid (ΔT min ) for self-heat exchange is required in order to use it as a heat circulator. The lower ΔT can improve COP of TE devices significantly.
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Experimental investigation of an active magnetic regenerative heat circulator applied to self-heat recuperation technology
Applied Thermal Engineering, 2014Co-Authors: Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:Abstract An experimental investigation into an active magnetic regenerative (AMR) heat circulator based on self-heat recuperation technology, was conducted to evaluate its energy saving potential in heat circulation. In an AMR heat circulator, magnetocaloric effect is applied to recuperate the heat exergy of the Process Fluid. The recuperated heat can be reused to heat the feed Process Fluid and realize self-heat recuperation. In this paper, AMR heat circulator has newly been constructed to determine the amount of heat circulated when applied to self-heat recuperation and the energy consumption of the heat circulator. Gadolinium and water was used as the magnetocaloric working material and the Process Fluid, respectively. The heat circulated amount was determined by measuring the temperature of the Process Fluid and gadolinium. The net work input for heat circulation was obtained from the magnetizing and demagnetizing forces and the distance travelled by the magnetocaloric bed. The results were compared with the minimum work input needed for heat circulation derived from exergy loss during heat exchange. It was seen that the experimentally obtained value was close to the minimum work input needed for heat circulation.
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Conceptual design of an active magnetic regenerative heat circulator based on self-heat recuperation technology
Energy, 2013Co-Authors: Yui Kotani, Yasuki Kansha, Atsushi TsutsumiAbstract:Abstract A conceptual design of an active magnetic regenerative (AMR) heat circulator for self-heat recuperation to realize energy savings in thermal Processes is proposed. The Process Fluid heat is recuperated by the magnetocaloric effect of ferromagnetic material through the AMR heat circulation cycle. In an AMR heat circulator, all the Process Fluid heat is circulated and no make-up heat is added to raise the Process Fluid to its set temperature. A one-dimensional mathematical model of the AMR heat circulator was constructed to understand its behavior and verify its energy-saving potential. From the constructed one-dimensional mathematical model, it is seen that AMR heat circulator has potential to drastically reduce the total energy consumption in a thermal Process. The temperature–entropy diagram shows that in order to gain the maximum energy saving, optimization of the parameters such as the flow rate and geometry of the ferromagnetic working material beds is needed.
Yui Kotani - One of the best experts on this subject based on the ideXlab platform.
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Theoretical and Experimental Investigation on the Energy Consumption of Self-heat Recuperation Using Magnetocaloric Effect
Chemical engineering transactions, 2014Co-Authors: Cal E, Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:The minimum energy consumption needed for heat circulation is derived from the exergy destruction due to heat exchange in terms of temperature-entropy diagram. The obtained value is compared with the numerical energy consumption when magnetocaloric effect is applied to self-heat recuperation technology. Furthermore, a magnetocaloric heat circulator has newly been constructed and its energy consumption has been measured. It is explained by the temperature-entropy diagram, that the minimum energy consumption needed for heat circulation is proportional to the minimum temperature difference needed for heat exchange. In a magnetocaloric heat circulator, the heat transfer between the Process Fluid and the working material is direct, thus leading to small temperature difference during heat exchange and small input work required for heat circulation.
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Self-heat Recuperative Heat Circulator with Thermoelectric Device☆
Energy Procedia, 2014Co-Authors: Renaldo N. Rasfuldi, Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:Abstract Self-heat recuperation (SHR) technology has been proven to reduce exergy loss in different Process systems, which lead to large energy savings due to its non-combustion Process. The purpose of this research is to develop a novel self-heat recuperative heat circulation system using thermoelectric (TE) device as a heat circulator for non-gaseous systems. Most research involving TE coolers is related to maximizing the temperature difference (ΔT) of a device, whereas in self-heat recuperative heat circulator, a large ΔT is not required, but only a minimum temperature difference between the surfaces of the TE device and Process Fluid (ΔT min ) for self-heat exchange is required in order to use it as a heat circulator. The lower ΔT can improve COP of TE devices significantly.
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Experimental investigation of an active magnetic regenerative heat circulator applied to self-heat recuperation technology
Applied Thermal Engineering, 2014Co-Authors: Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:Abstract An experimental investigation into an active magnetic regenerative (AMR) heat circulator based on self-heat recuperation technology, was conducted to evaluate its energy saving potential in heat circulation. In an AMR heat circulator, magnetocaloric effect is applied to recuperate the heat exergy of the Process Fluid. The recuperated heat can be reused to heat the feed Process Fluid and realize self-heat recuperation. In this paper, AMR heat circulator has newly been constructed to determine the amount of heat circulated when applied to self-heat recuperation and the energy consumption of the heat circulator. Gadolinium and water was used as the magnetocaloric working material and the Process Fluid, respectively. The heat circulated amount was determined by measuring the temperature of the Process Fluid and gadolinium. The net work input for heat circulation was obtained from the magnetizing and demagnetizing forces and the distance travelled by the magnetocaloric bed. The results were compared with the minimum work input needed for heat circulation derived from exergy loss during heat exchange. It was seen that the experimentally obtained value was close to the minimum work input needed for heat circulation.
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Conceptual design of an active magnetic regenerative heat circulator based on self-heat recuperation technology
Energy, 2013Co-Authors: Yui Kotani, Yasuki Kansha, Atsushi TsutsumiAbstract:Abstract A conceptual design of an active magnetic regenerative (AMR) heat circulator for self-heat recuperation to realize energy savings in thermal Processes is proposed. The Process Fluid heat is recuperated by the magnetocaloric effect of ferromagnetic material through the AMR heat circulation cycle. In an AMR heat circulator, all the Process Fluid heat is circulated and no make-up heat is added to raise the Process Fluid to its set temperature. A one-dimensional mathematical model of the AMR heat circulator was constructed to understand its behavior and verify its energy-saving potential. From the constructed one-dimensional mathematical model, it is seen that AMR heat circulator has potential to drastically reduce the total energy consumption in a thermal Process. The temperature–entropy diagram shows that in order to gain the maximum energy saving, optimization of the parameters such as the flow rate and geometry of the ferromagnetic working material beds is needed.
Paul Stonestreet - One of the best experts on this subject based on the ideXlab platform.
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operation and optimization of an oscillatory flow continuous reactor
Industrial & Engineering Chemistry Research, 2001Co-Authors: Adam Harvey, Malcolm R. Mackley, Paul StonestreetAbstract:Oscillatory flow reactors (OFRs) are a novel type of continuous reactor, in which tubes fitted with orifice plate baffles have an oscillatory motion superimposed upon the net flow of the Process Fluid. The combination of baffles and the oscillatory motion creates a flow pattern conducive to efficient heat and mass transfer while maintaining plug flow. Unlike conventional tubular reactors, where a minimum Reynolds number must be maintained, tube-side mixing is independent of the net flow, allowing long residence times to be achieved in a reactor of greatly reduced length-to-diameter ratio. We have evaluated a pilot-scale OFR as a method for continuous production of sterols in an ester saponification reaction. The OFR achieved the required product specification, in a residence time one-eighth that of a full-scale batch reactor. To better understand the effect of the Process variables on the reactor performance, the OFR was modeled using a tanks-in-series residence time distribution, combined with the saponi...