The Experts below are selected from a list of 95328 Experts worldwide ranked by ideXlab platform
Syu-fang Liu - One of the best experts on this subject based on the ideXlab platform.
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Effect of non-uniform Inlet Flow rate on the heat-up process of a solid oxide fuel cell unit with cross-Flow configuration
International Journal of Hydrogen Energy, 2016Co-Authors: Ping Yuan, Syu-fang LiuAbstract:Abstract This study simulates the heat-up process of a solid oxide fuel cell unit with the cross-Flow configuration, and investigates the effect of the non-uniform Inlet Flow pattern and the non-uniform deviation on the maximum temperature gradient and preheating time. The numerical method is precise and reliable through the comparison with the analytical solution of previous literature. The results show that the effect of non-uniform Inlet Flow pattern on the maximum temperature gradient is obvious, and the effect in the fuel side is more obvious than that in the air side. The best choice of the Inlet Flow pattern is C, which the fuel side is uniform and the air side is the progressively increasing profile. Additionally, the effect of non-uniform Inlet Flow pattern on the preheating time can not be neglected, and this effect becomes larger when the non-uniform deviation increases.
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Numerical Analysis of Temperature and Current Density Distribution of a Planar Solid Oxide Fuel Cell Unit with Nonuniform Inlet Flow
Numerical Heat Transfer Part A: Applications, 2007Co-Authors: Ping Yuan, Syu-fang LiuAbstract:This study investigates temperature and current density distribution in a planar solid oxide fuel cell unit with cross-Flow configuration when fuel and air Inlet Flows are nonuniform. The numerical method in this study solves two-dimensional, simultaneous, partial differential equations of mass, energy, and electrochemistry, without considering stack direction variation. Fuel and air dominate cell current density and temperature as results indicate, and nonuniform Inlet Flow effect on cell temperature and current density distribution are apparent. Air Inlet Flow with a progressively decreasing profile will additionally induce higher cell temperature on the hot spot located in the fuel and air exit corner, and enlarge cell plane temperature difference by 10% compared to that in the uniform profile. Nonuniform fuel Inlet Flow also increases current density difference more than 10% compared to the uniform profile.
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Effect of Inlet Flow maldistribution on the thermal and electrical performance of a molten carbonate fuel cell unit
Journal of Power Sources, 2006Co-Authors: Syu-fang Liu, Hsin-sen Chu, Ping YuanAbstract:This study investigates the temperature and current density distributions in a molten carbonate fuel cell unit when the Inlet Flows of the anode gas and the cathode gas are mal-distributed in eight patterns. The two-dimensional simultaneous partial differential equations of mass, energy and electrochemistry are solved numerically. The results indicate that the maldistribution of anode and cathode gases dominates the current density field and the cell temperature field, respectively. Moreover, the non-uniform Inlet Flow slightly affects the mean temperature and mean current density, but worsens the distribution of temperature and current density for most maldistribution patterns. According to the results, the variations of the cell temperature in Pattern G and the current density in Pattern D are 12% and 37% greater than those in the uniform pattern when the deviation of the non-uniform profile is 0.25. Consequently, the effect of non-uniform Inlet Flow on the temperature and current density distribution on the cell plane is evident, and cannot be neglected.
Ping Yuan - One of the best experts on this subject based on the ideXlab platform.
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Effect of non-uniform Inlet Flow rate on the heat-up process of a solid oxide fuel cell unit with cross-Flow configuration
International Journal of Hydrogen Energy, 2016Co-Authors: Ping Yuan, Syu-fang LiuAbstract:Abstract This study simulates the heat-up process of a solid oxide fuel cell unit with the cross-Flow configuration, and investigates the effect of the non-uniform Inlet Flow pattern and the non-uniform deviation on the maximum temperature gradient and preheating time. The numerical method is precise and reliable through the comparison with the analytical solution of previous literature. The results show that the effect of non-uniform Inlet Flow pattern on the maximum temperature gradient is obvious, and the effect in the fuel side is more obvious than that in the air side. The best choice of the Inlet Flow pattern is C, which the fuel side is uniform and the air side is the progressively increasing profile. Additionally, the effect of non-uniform Inlet Flow pattern on the preheating time can not be neglected, and this effect becomes larger when the non-uniform deviation increases.
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Numerical Analysis of Temperature and Current Density Distribution of a Planar Solid Oxide Fuel Cell Unit with Nonuniform Inlet Flow
Numerical Heat Transfer Part A: Applications, 2007Co-Authors: Ping Yuan, Syu-fang LiuAbstract:This study investigates temperature and current density distribution in a planar solid oxide fuel cell unit with cross-Flow configuration when fuel and air Inlet Flows are nonuniform. The numerical method in this study solves two-dimensional, simultaneous, partial differential equations of mass, energy, and electrochemistry, without considering stack direction variation. Fuel and air dominate cell current density and temperature as results indicate, and nonuniform Inlet Flow effect on cell temperature and current density distribution are apparent. Air Inlet Flow with a progressively decreasing profile will additionally induce higher cell temperature on the hot spot located in the fuel and air exit corner, and enlarge cell plane temperature difference by 10% compared to that in the uniform profile. Nonuniform fuel Inlet Flow also increases current density difference more than 10% compared to the uniform profile.
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Effect of Inlet Flow maldistribution on the thermal and electrical performance of a molten carbonate fuel cell unit
Journal of Power Sources, 2006Co-Authors: Syu-fang Liu, Hsin-sen Chu, Ping YuanAbstract:This study investigates the temperature and current density distributions in a molten carbonate fuel cell unit when the Inlet Flows of the anode gas and the cathode gas are mal-distributed in eight patterns. The two-dimensional simultaneous partial differential equations of mass, energy and electrochemistry are solved numerically. The results indicate that the maldistribution of anode and cathode gases dominates the current density field and the cell temperature field, respectively. Moreover, the non-uniform Inlet Flow slightly affects the mean temperature and mean current density, but worsens the distribution of temperature and current density for most maldistribution patterns. According to the results, the variations of the cell temperature in Pattern G and the current density in Pattern D are 12% and 37% greater than those in the uniform pattern when the deviation of the non-uniform profile is 0.25. Consequently, the effect of non-uniform Inlet Flow on the temperature and current density distribution on the cell plane is evident, and cannot be neglected.
Paul G. Tucker - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Inlet Guide Vanes on Inlet Flow Distortion Transfer and Transonic Fan Stability
Journal of Turbomachinery, 2013Co-Authors: Mj Shaw, P Hield, Paul G. TuckerAbstract:An investigation was carried out into the effects of variable Inlet guide vanes (VIGVs) on the performance and stability margin of a transonic fan in the presence of Inlet Flow distortion. The study was carried out using computational fluid dynamics (CFD) and validated with experimental data. The capability of CFD to predict the changes in performance with or without VIGVs in the presence of an Inlet Flow distortion is assessed. Results show that the VIGVs improve the performance and stability margin and do so by reducing the amount of swirl at Inlet to the rotor component of the fan.
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The Effect of Inlet Guide Vanes on Inlet Flow Distortion Transfer and Transonic Fan Stability
Volume 6A: Turbomachinery, 2013Co-Authors: Mj Shaw, P Hield, Paul G. TuckerAbstract:An investigation has been carried out into the effects of variable Inlet guide vanes (VIGVs) on the performance and stability margin of a transonic fan in the presence of Inlet Flow distortion. The study was carried out using computational fluid dynamics (CFD) and validated with experimental data. The capability of CFD to predict the changes in performance with or without VIGVs in the presence of an Inlet Flow distortion is assessed. Results show that the VIGVs improve the performance and stability margin and do so by reducing the amount of swirl at Inlet to the rotor component of the fan.Copyright © 2013 by Rolls-Royce plc
H. Starken - One of the best experts on this subject based on the ideXlab platform.
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Inlet Flow angle determination of transonic compressor cascades
Journal of Turbomachinery, 1992Co-Authors: W. Steinert, R. Fuchs, H. StarkenAbstract:Tests of transonic compressor cascades require special measuring techniques to determine the Inlet Flow angle around sonic Inlet Flow conditions. One of the main requirements for these methods is the ability to adjust the Inlet Flow angle during the test to a prescribed value. A method has been successfully applied that relies on theoretically determined suction surface velocities. The described method was applied in testing cascades at Inlet Mach numbers between M 1 =0.75-1.18. The test results confirmed the practicability of this method
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Inlet Flow Angle Determination of Transonic Compressor Cascades
Volume 1: Turbomachinery, 1991Co-Authors: W. Steinert, R. Fuchs, H. StarkenAbstract:Tests of transonic compressor cascades require special measuring techniques to determine the Inlet Flow angle around sonic Inlet Flow conditions. One of the main requirements for these methods is the ability to adjust the Inlet Flow angle during the test to a prescribed value. A method has been successfully applied which relies on theoretically determined suction surface velocities. The described method was applied in testing cascades at Inlet Mach numbers between M1=0.75–1.18. The test results confirmed the practicability of this method.Copyright © 1991 by ASME
Peter Rosander - One of the best experts on this subject based on the ideXlab platform.
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practical control of surge tanks suffering from frequent Inlet Flow upsets
IFAC Proceedings Volumes, 2012Co-Authors: Peter Rosander, Alf J Isaksson, Johan Lofberg, Krister ForsmanAbstract:In the presence of frequent Inlet Flow upsets, tuning of averaging level controllers is typically quite complicated since not only the size of the individual steps but also the time in between the subsequent steps need to considered. One structured way to achieve optimal filtering for such a case is to use Robust Model Predictive Control. The robust MPC controller is, however, quite computationally demanding and not easy to implement. In this paper two linear controllers, which mimic the behavior of the robust MPC, are proposed. Tuning guidelines to avoid violation of the tank level constraints as well as to achieve optimal filtering are presented.
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practical control of surge tanks suffering from frequent Inlet Flow upsets
2nd IFAC Conference on Advances in PID Control Brescia Italy 28-30 March 2012, 2012Co-Authors: Peter Rosander, Alf J Isaksson, Johan Lofberg, Krister ForsmanAbstract:In the presence of frequent Inlet Flow upsets, tuning of averaging level controllers is typically quite complicated since not only the size of the individual steps but also the time in between the subsequent steps need to considered. One structured way to achieve optimal filtering for such a case is to use Robust Model Predictive Control. The robust MPC controller is, however, quite computationally demanding and not easy to implement. In this paper two linear controllers, which mimic the behavior of the robust MPC, are proposed. Tuning guidelines to avoid violation of the tank level constraints as well as to achieve optimal filtering are presented.
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Averaging level control in the presence of frequent Inlet Flow upsets
2012Co-Authors: Peter RosanderAbstract:Buffer tanks are widely used within the process industry to prevent Flow variations from being directly propagated throughout a plant. The capacity of the tank is used to smoothly transfer Inlet Flow upsets to the outlet. Ideally, the tank thus works as a low pass filter where the available tank capacity limits the achievable Flow smoothing. For infrequently occurring upsets, where the system has time to reach steady state between Flow changes, the averaging level control problem has been extensively studied. After an Inlet Flow change, Flow filtering has traditionally been obtained by letting the tank level deviate from its nominal value while slowly adapting the outlet to cancel out the Flow imbalance and eventually bringing back the level to its set-point. The system is then again in steady state and ready to surge the next upset. By ensuring that the single largest upset can be handled without violating the level constraints, satisfactory Flow smoothing is obtained. In this thesis, the smoothing of frequently changing Inlet Flows is addressed. In this case, standard level controllers struggle to obtain acceptable Flow smoothing since the system rarely is in steady state and Flow upsets can thus not be treated as separate events. To obtain a control law that achieves optimal filtering while directly accounting for future upsets, the averaging level control problem was approached using robust model predictive control (MPC). The robust MPC differs in the way it obtains Flow smoothing by not returning the tank level to a fixed set-point. Instead, it lets the steady state tank level depend on the current value of the Inlet Flow. This insight was then used to propose a linear control structure, designed to filter frequent upsets optimally. Analyses and simulation results indicate that the proposed linear and robust MPC controller obtain Flow smoothing comparable to the standard optimal averaging level controllers for infrequent upsets while handling frequent upsets considerably better.
