For predicting the thermal performance of cold box with parallel plate-fin heat exchangers, a general distributed-parameter model based on graph theory was developed. In the present study, a mathematical description m...
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For predicting the thermal performance of cold box with parallel plate-fin heat exchangers, a general distributed-parameter model based on graph theory was developed. In the present study, a mathematical description model of cold box based on graph theory was established, capable of describing the connection relations of multiple streams and components in cold box;a distributed-parameter thermal performance model of plate-fin heat exchangers based on approximate analytical method was developed, and the temperature gradients along both axial and transversal directions are reflected;a mass flow rate distribution model of parallel pipelines based on the pressure balance was presented to calculate the flow distribution of multiple streams in pipelines. A tailor-made iteration algorithm using graph-based traversal method was developed to solve the present model. The validation of the proposed model shows that the deviations of the calculated heat capacity and outlet temperature of natural gas from experimental data are -1.9% and +4.35 degrees C, respectively.
NASA Technical Reports Server (Ntrs) 20060053356: Model Predictive Optimal Control of a Time-Delay distributed-parameter Systems by NASA Technical Reports Server (Ntrs); published by
NASA Technical Reports Server (Ntrs) 20060053356: Model Predictive Optimal Control of a Time-Delay distributed-parameter Systems by NASA Technical Reports Server (Ntrs); published by
This paper presents a conception of an exponential observer for a class of linear distributed-parameter systems (DPSs), in which the dynamics are partially unknown. The given distributed-parameter observer ensures asy...
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This paper presents a conception of an exponential observer for a class of linear distributed-parameter systems (DPSs), in which the dynamics are partially unknown. The given distributed-parameter observer ensures asymptotic state estimator with exponentially decay error, based on the theory of C0-semigroups in a Hilbert space. The theoretical observer developed is applied to a chemical tubular reactor, namely the isothermal Plug-Flow reactor basic dynamical model for which measurements are available at the reactor output only. The process is described by Partial differential equations with unknown initial states. For this application, performance issues are illustrated in a simulation study.
A 25Hz phase-sensitive track circuit is used in electrified railway stations allowing determination of whether a train occupies a track section and avoiding the interference of traction current to signal circuit. The ...
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A 25Hz phase-sensitive track circuit is used in electrified railway stations allowing determination of whether a train occupies a track section and avoiding the interference of traction current to signal circuit. The transmission characteristics of a 25Hz phase-sensitive track circuit in the regulated state were studied, allowing the development of a model of choke transformer and track circuit. Considering the impedance bond, a four-terminal network model that adjusts the state of track circuit was built, and a distributed-parameter method was applied to solve the four-terminal network coefficient of the track circuit in the regulated state. The sinusoidal steady-state responses can be obtained directly from the complex frequency-domain solution, and the DC steady-state response can be calculated using the final value theorem of Laplace transform theory. This steady-state analysis of track circuit transmission lines allows the characteristic analysis of track circuit during steady state operation. This work also can serve as guidance to help ensure signal transmission without distortion. Finally, the transmission characteristics of the track circuit were simulated by Matlab. The simulation results show that the transmission characteristics of the track circuit in regulated state is closely related to the length of the track circuit and ballast resistance.
The non-uniform distributions of two-dimensional radiation flux on the surfaces of water-cooled wall in a furnace are obtained through the three-dimensional flue gas temperature distributions and the furnace radiation...
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ISBN:
(纸本)9781424425020
The non-uniform distributions of two-dimensional radiation flux on the surfaces of water-cooled wall in a furnace are obtained through the three-dimensional flue gas temperature distributions and the furnace radiation energy signals, which are got by a real-time monitoring system for the three-dimensional combustion. By the radiation flux distributions taken as the boundary conditions, a dynamic model for the boiler is established. A simulation is made on a 300MW power plant boiler. Taking the measured data of the power plant as the inputs of the model, the average wall heat flux, drum pressure and steam mass flow rate at the outlet of the drum are calculated. The simulated results are compared with the measured data, which show the model can well represent the dynamic process of the boiler. The model is expected to be useful for on-line prediction or off-line calculation because of the performance of calculation of important thermodynamic parameter distributions on the water-cooled wall including the wall heat flux, wall temperature, steam content in mass and mass velocity, which provide an important basis to evaluate the security and reliability of power plant boiler.
A four-link pendulum, with two flexure hinges, is presented. The system is described by a non-linear distributed-parameter model. By assuming the deformation of a compliant link is identical to the static deflection, ...
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A four-link pendulum, with two flexure hinges, is presented. The system is described by a non-linear distributed-parameter model. By assuming the deformation of a compliant link is identical to the static deflection, the model number of degrees of freedom reduces to two. The finite element results validate the analytic model. A search is conducted to select the designs that determine the free extremity moving along a prescribed trajectory. A pendulum prototype produced a quasi-elliptical trajectory, according to model predictions. (C) 2001 Elsevier Science Ltd. All rights reserved.
Two infiltration models, called VVSIM (variable variance stochastic infiltration model) and EVVSIM (enhanced variable variance stochastic infiltration model), are developed in this study. A distributedparameter infil...
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Two infiltration models, called VVSIM (variable variance stochastic infiltration model) and EVVSIM (enhanced variable variance stochastic infiltration model), are developed in this study. A distributedparameter infiltration model can estimate the amount of infiltration over a field area by computing the infiltration over zones of the field area. Hydraulic conductivity is the most important parameter determining infiltration in simulations by infiltration models. The performance of an infiltration model depends on how well the model accommodates the complicated spatial distribution of hydraulic conductivity. The two proposed models include the effects of spatial correlation of the conductivity distribution. Virtual conductivity fields are generated using the turning bands method. Monte Carlo simulations show that the proposed models give infiltration estimates more accurate than those obtained by the other models employed.
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