The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
R. S. Amano - One of the best experts on this subject based on the ideXlab platform.
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Water Spray Cooling of High-Temperature Steam Flow Through a Steam Turbine Bypass Valve Line
Volume 3: Thermal Hydraulics; Current Advanced Reactors: Plant Design Construction Workforce and Public Acceptance, 2009Co-Authors: R. S. AmanoAbstract:The objective of the present study is to investigate the steam flow behavior through the high-pressure turbine Bypass Valve. Efforts have mainly been directed at investigating the process of steam flow and property variations aforementioned Bypass Valve as well as to obtain correlations between the flow rate and the Valve opening ratio. Modeling of the high-pressure turbulent steam flow was performed on a three-dimensional non-staggered (co-located) grid system by employing the finite volume method and by solving the three-dimensional, turbulent, compressible Navier-Stokes, and energy equations. Through this research, numerous data have been acquired and analyzed. These efforts enable us to obtain a correlation data set for the flow rate coefficient as a function of Valve opening. One of the significant accomplishments is to use the model presented here for further improve a design of a turbine Bypass flow Valve.Copyright © 2009 by ASME
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Flow in Duct Downstream of a Steam Turbine Bypass Valve
ASME 2006 Power Conference, 2006Co-Authors: R. S. AmanoAbstract:The main goal of this study is to investigate the evaporation process of a coolant (water droplets) which is injected through spray nozzles mounted on a steam turbine Bypass pipeline in a co-generator system. The study includes several important factors: (1) the effects of four elbows on the flow pattern and evaporation process of the water particles, (2) heat transfer that affects the steam temperature and also the evaporation rates, and (3) the effects of a perforated plate on the flow pattern and evaporation process. The investigation of the structure of liquid spray jets during the transition into the gaseous phase was accomplished by developing a physical model of a particle tracking technique to investigate evaporation processes of the liquid droplets in a highly turbulent flow. Through this research, numerous data have been acquired and analyzed for heat transfer mechanisms of the evaporation of the water droplets in the pipeline system along with the cooling of the steam flow. The results of the computations were verified by comparing them with theoretical models, and were shown to be quite reliable.Copyright © 2006 by ASME
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High-Temperature and High-Pressure Steam Flow Through a Steam Turbine Bypass Valve Line
ASME 2005 Power Conference, 2005Co-Authors: R. S. AmanoAbstract:The objective of the present study is to investigate the steam flow behavior through the high-pressure turbine Bypass Valve. Efforts have mainly been directed at investigating the process of steam flow and property variations aforementioned Bypass Valve as well as to obtain correlations between the flow rate and the Valve opening ratio. Modeling of the high-pressure turbulent steam flow was performed on a three-dimensional non-staggered (co-located) grid system by employing the finite volume method and by solving the three-dimensional, turbulent, compressible Navier-Stokes, and energy equations. Through this research, numerous data have been acquired and analyzed. These efforts enable us to obtain a correlation data set for the flow rate coefficient as a function of Valve opening. One of the significant accomplishments is to use the model presented here for further improve a design of a turbine Bypass flow Valve.Copyright © 2005 by ASME
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High-Pressure Steam Flow in Turbine Bypass Valve System Part 1: Valve Flow
Journal of Propulsion and Power, 2002Co-Authors: R. S. Amano, G. R. DraxlerAbstract:This paper presents a study of steam e ow behavior through a high-pressure turbine Bypass Valve when it suffers a high-pressure reduction in an electric-power-plant cogeneratorsystem. Efforts have been mainly directed at investigating the process of steam e ow and property variations in the aforementioned Bypass Valve as well as at obtaining correlations between the e ow rate and the Valve opening ratio. Modeling of the high-pressure turbulent steam e ow was performed on a three-dimensional nonstaggered grid system by employing the e nite volume differencing method and by solving the three-dimensional, turbulent, compressible Navier ‐Stokes and energy equations. Through this research numerous data have been acquired and analyzed. These efforts enable us to obtain a correlation data set for the Valve-opening vs the e ow rate coefe cient of the Valve. One of the signie cant accomplishments isto use the model presented here to further improvethedesign of a high-pressuresteam turbine Bypass e ow Valve to reduce a high-velocity spot in the Valve e ow pass so that noise can be suppressed.
Deng Kang-yao - One of the best experts on this subject based on the ideXlab platform.
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Experiment on Characteristic of Bypass Valves and Regulating MAP of a Regulated Two-Stage Turbocharged Diesel Engine
Transactions of Csice, 2012Co-Authors: Deng Kang-yaoAbstract:Experimental study was conducted on a regulated two-stage turbocharged(R2S)diesel engine.The Bypass Valve of turbine is parallel which locates with the high pressure stage turbine,through which the boost pressure is regulated and engine performance varies.At low to middle engine speed,the R2S system improves boost level and reduces smoke emission.Torque at full load is increased when fuel rate is increased.Compared to base engine,fuel consumption reduces obviously due to combustion improvement at low to middle engine speed and middle to high load by two stages turbocharging.At middle to high engine speed,higher boost pressure does not improve combustion,on the contrary,deteriorates the pump loss.Therefore,from the economy aspect,Bypass Valve of turbine should be full opening at those operating points.Accordingly,the compressor Bypass Valve should also be opened to reduce the flow loss.Fuel consumption slightly increases due to non-optimized complex intake and exhaust system due to Bypass.
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Experimental on Load Transit Performance of Diesel Engine with Regulated Two Stage Turbocharging System
Transactions of Csice, 2012Co-Authors: Deng Kang-yaoAbstract:Experimental study during load transit was conducted on a regulated two stage turbocharging(R2S) diesel engine.Transient test system of diesel engine with R2S was built.Regulating maps of R2S Bypass Valves were analyzed through the comprehensive steady-state experiment.Experimental method of load transit process was determined based on the steady-state regulating maps of Bypass Valves.Load transit performance test at same speed was conducted under three speed lines.Experimental results showed that the turbine Bypass Valve should be closed at low speed and high load.At low load,Bypass Valve was also closed to avoid the slowly rising of boost pressure and poor emissions performance.One modified regulating map was proposed to improve the response of turbocharging system of diesel engine.Meanwhile,smoke emission was improved.
G S Samuelsen - One of the best experts on this subject based on the ideXlab platform.
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power and temperature control of fluctuating biomass gas fueled solid oxide fuel cell and micro gas turbine hybrid system
Journal of Power Sources, 2006Co-Authors: T Kaneko, Jacob Brouwer, G S SamuelsenAbstract:Abstract This paper addresses how the power and temperature are controlled in a biomass gas fueled solid oxide fuel cell (SOFC) and micro gas turbine (MGT) hybrid system. A SOFC and MGT dynamic model are developed and used to simulate the hybrid system performance operating on biomass gas. The transient behavior of both the SOFC and MGT are discussed in detail. An unstable power output is observed when the system is fed biomass gas. This instability is due to the fluctuation of gas composition in the fuel. A specially designed fuel controller succeeded not only in allowing the hybrid system to follow a step change of power demand from 32 to 35 kW, but also stably maintained the system power output at 35 kW. In addition to power control, fuel cell temperature is controlled by introduction and use of a Bypass Valve around the recuperator. By releasing excess heat to the exhaust, the Bypass Valve provided the control means to avoid the self-exciting behavior of system temperature and stabilized the temperature of SOFC at 850 °C.
Norman M. Wereley - One of the best experts on this subject based on the ideXlab platform.
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advanced magnetorheological damper with a spiral channel Bypass Valve
Journal of Applied Physics, 2014Co-Authors: G Mclaughlin, W Hu, Norman M. WereleyAbstract:Magnetorheological (MR) fluid has a yield stress that is readily controllable using an applied magnetic field. MR dampers adjust this yield stress in a magnetic Valve to accommodate a wide range of shock or vibration loads. In this study, the performance of an MR damper with a spiral channel Bypass Valve is examined. Three Bypass damper configurations, i.e., a spiral channel, a spiral channel with beads, and a straight channel with beads, are subject to sinusoidal forcing at constant amplitude, while varying frequency, and applied field (current). These configurations are characterized using tortuosity and porosity parameters. The spiral channel without beads had the largest porosity and smallest tortuosity, which produced the smallest damper force, but the widest controllable damping range. The spiral channel with beads had the smallest porosity, and a comparable tortuosity, which produced the largest damping force, but similar controllable damping range to the straight channel with beads.
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magnetorheological Bypass damper exploiting flow through a porous channel
Journal of Intelligent Material Systems and Structures, 2007Co-Authors: Eugene Cook, Wei Hu, Norman M. WereleyAbstract:A magnetorheological (MR) damper with a Bypass Valve containing porous media is developed. Movement of the piston forces MR fluid to flow from one side of the piston to the other, through an externally mounted Bypass packed with magnetic spheres. The passageways between the spheres provide narrow, tortuous channels that act as a controllable Valve when subjected to a magnetic field. A stationary magnetic coil is wrapped around the so-called porous Valve, which is isolated from the MR fluid and external to the primary hydraulic cylinder. While flowing through the tortuous channels in the porous media created by the packed spheres, the MR fluid experiences varied local flow directions, and thus an external field can be applied in any direction to adjust damping levels. Additionally, the use of long channels, which are tightly packed to create narrow passageways, allows a very high damping force to be generated by a relatively compact damper. Furthermore, use of an externally mounted coil allows for maintenance accessibility, and the magnetic flux return path can be either empty (air) or any high permeability material. The damper is tested for steady-state sinusoidal displacements, and equivalent viscous damping and complex stiffness are computed. It is shown that the porous Bypass Valve MR damper can provide high controllable damping force and a wide force range.
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Energy Absorber Using a Magnetorheological Bypass Valve Filled With Ferromagnetic Beads
IEEE Transactions on Magnetics, 2007Co-Authors: Wei Hu, Eugene Cook, Norman M. WereleyAbstract:An energy absorber using a magnetorheological (MR) Bypass Valve filled with ferromagnetic beads was designed, fabricated, and its performance evaluated empirically. Spherical ferromagnetic beads were randomly packed inside a hollow nonmagnetic stainless steel tube comprising the Bypass Valve body. A key objective was to understand the interaction of magnetic and fluidic mechanisms as the MR fluid flows through a cylinder of randomly packed ferromagnetic beads. Behavior of the energy absorber using different diameters of ferromagnetic beads was measured using a servo-hydraulic testing machine. The relationship between the damping performance of the energy absorber and the ferromagnetic bead diameter was evaluated in terms of maximum controllable damping force, damping control range, and frequency bandwidth
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Liquid Spring Shock Absorber with Controllable Magnetorheological Damping
Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2006Co-Authors: Sung-ryong Hong, Wei Hu, Gang Wang, Norman M. WereleyAbstract:AbstractAn automotive suspension strut is investigated that utilizes compressible magnetorheological (CMR) fluid. A CMR strut consists of a double-ended rod in a hydraulic cylinder and a Bypass comprising tubing and an MR Valve. The diameter of the rods on either side of the piston are set to be different in order to develop spring force by compressing the MR fluid hydrostatically as a result of varying shaft volume in the hydraulic cylinder. The MR Bypass Valve is adopted to develop a controllable damping force. A hydromechanical model of the CMR strut is derived by considering lumped hydraulic parameters such as compliances of chambers inside the cylinder and flow resistances through the MR Bypass Valve. The spring force and nominal spring rate owing to fluid compressibility and the controllable flow resistance and pressure drop in the Bypass were analytically investigated on the basis of the model. Finally, a CMR strut, filled with silicone oil-based MR fluid, is fabricated and tested. The spring force...
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Characterization and Modeling Magnetorheological By-Pass Porous Damper Exploiting Flow Through a Porous Media
Aerospace, 2006Co-Authors: Wei Hu, Eugene Cook, Norman M. WereleyAbstract:A magnetorheological (MR) fluid Bypass damper exploiting flow through porous media is developed utilizing a Valve filled with porous media instead of regular uniform channels to adaptively regulate damping force. The MR damper includes a cylinder containing an MR fluid, a movable piston and a Bypass Valve. The Bypass Valve filled with porous media is used to provide a magnetically energizable passageway. A stationary magnetic coil is wrapped around the Bypass Valve, isolated from the MR fluid and external to the device. The axis of the Bypass Valve is collinear with the center of the magnetic coil such that the magnetic flux return guide of the coil can be either empty (air) or any high permeability steel material which provides flexibility for damper design. The damper is applied with sinusoidal excitations. Equivalent viscous damping is used to characterize the damper. It is shown that the MR damper exploiting flow through porous media can provide high controllable damping force using a compact damper configuration. To describe the behavior of the MR damper, the flow path in the porous media is considered as a multiple-pipe system. Using quantitative and empirical analysis of the magnetic and rheological properties of MR fluid flowing through the porous media in the Bypass Valve, the controllable damping performance of the damper is well predicted using the model, and the force-displacement hysteresis behavior of the damper can also be described by the analytical model. The model is validated by the experimental data at different frequencies and applied currents.Copyright © 2006 by ASME
Harald Aschemann - One of the best experts on this subject based on the ideXlab platform.
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Input-output linearisation with input constraints for an innovative engine cooling system
2014 European Control Conference (ECC), 2014Co-Authors: Saif Siddique Butt, Robert Prabel, Harald AschemannAbstract:A nonlinear control approach of an innovative engine cooling system for vehicles is presented in this paper. The electrically driven coolant pump and a servo-controlled Bypass Valve as control inputs, however, are subject to saturation due to physical limitations of the maximum pump volume flow and the limited opening section of the Bypass Valve. Based on a control-oriented system representation, a decoupling, input-output-linearising control is designed for the engine outlet temperature and the engine inlet temperature. At this control design, the given actuator limitations are explicitly taken into account. The multi-variable control is implemented with a small sampling time and combined with a discrete-time Extended Kalman Filter that estimates unknown heat flows within the system. Experimental results from a dedicated test rig highlight the effectiveness and the performance of the proposed control approach.
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ECC - Input-output linearisation with input constraints for an innovative engine cooling system
2014 European Control Conference (ECC), 2014Co-Authors: Saif Siddique Butt, Robert Prabel, Harald AschemannAbstract:A nonlinear control approach of an innovative engine cooling system for vehicles is presented in this paper. The electrically driven coolant pump and a servo-controlled Bypass Valve as control inputs, however, are subject to saturation due to physical limitations of the maximum pump volume flow and the limited opening section of the Bypass Valve. Based on a control-oriented system representation, a decoupling, input-output-linearising control is designed for the engine outlet temperature and the engine inlet temperature. At this control design, the given actuator limitations are explicitly taken into account. The multi-variable control is implemented with a small sampling time and combined with a discrete-time Extended Kalman Filter that estimates unknown heat flows within the system. Experimental results from a dedicated test rig highlight the effectiveness and the performance of the proposed control approach.
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Robust input-output linearization with input constraints for an engine cooling system
2014 American Control Conference, 2014Co-Authors: Saif Siddique Butt, Robert Prabel, Harald AschemannAbstract:In this paper, a nonlinear control approach of an innovative engine cooling system for vehicles is presented. The electrically driven coolant pump and a servo-controlled Bypass Valve as control inputs, however, are subject to saturation due to physical limitations of the maximum pump volume flow and the limited opening section of the Bypass Valve. Based on a control-oriented system representation, a robust decentralized control employing sliding-mode techniques is proposed: an input-output linearizing control is designed for the engine outlet temperature, whereas an exact linearization is performed for the engine inlet temperature. At this control design, the given actuator limitations are explicitly taken into account. The controllers are implemented with small sampling time and combined with a discrete-time Extended Kalman Filter that estimates unknown heat flows within the system. In an experimental investigation, the performance of two alternative stabilizing control laws is compared: a linear stabilizing control law as reference and the robust sliding-mode approach leading to a nonlinear error dynamics. The obtained results highlight the effectiveness and the control performance of the proposed robust control strategy.
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Nonlinear model-predictive control for an engine cooling system with smart Valve and pump
2014 19th International Conference on Methods and Models in Automation and Robotics (MMAR), 2014Co-Authors: Saif Siddique Butt, Robert Prabel, Robert Grimmecke, Harald AschemannAbstract:In this paper, a nonlinear control approach based on a control-oriented model of an engine cooling system for vehicles is presented. An electrically driven coolant pump and a servo-controlled Bypass Valve act as control inputs. Due to physical limitations regarding the volume flow provided by the coolant pump as well as the opening section of the servo-controlled Bypass Valve, a constrained control problem arises. Therefore, a nonlinear model-predictive controller is employed, which explicitly takes the actuator limitations into account. A reduced-order disturbance observer is used to estimate unmeasured heat flows within the system in order to obtain a reliable prediction. An experimental analysis highlights the effectiveness of the nonlinear model-predictive control strategy in combination with a reduced-order observer.
