scholarly journals Identification of Solar Collector Dynamics Using Physical Model-Based Approach

1994 ◽  
Vol 116 (4) ◽  
pp. 755-763 ◽  
Author(s):  
B. J. Huang ◽  
S. B. Wang
Keyword(s):  
Steady State ◽  
System Dynamics ◽  
Physical Model ◽  
Transfer Functions ◽  
Linear Time ◽  
Operating Conditions ◽  
Distributed Model ◽  
Response Analysis ◽  
Linear Perturbation ◽  
Model Parameters

A system dynamics model of flat-plate solar collectors was derived and identified here. A nonlinear physical model was first derived from a two-node concept and energy conservation principle. The model was then approximated by the linear perturbation equations which were Laplace transformed and solved to lead to a distributed model in terms of the transfer functions. A model reduction was further employed to yield a linear time-invariant model with parameters as functions of steady-state operating conditions. The model parameters were identified by a dynamic test with step inputs at various operating conditions using frequency response analysis and model fitting in frequency domain. The identified parameters were then fitted to a function of steady-state mass flowrate mw. Thus, the model can describe the system dynamics behavior under various operating conditions through the identified parameters. The simulations using the model were shown to agree very well with the test results.

Using Sliding Mode Control to Adjust Drum Level of a Boiler Unit With Time Varying Parameters

2010 ◽  
Author(s):  
Hamed Moradi ◽  
Firooz Bakhtiari-Nejad ◽  
Majid Saffar-Avval ◽  
Aria Alasty
Keyword(s):  
Water Level ◽  
Transfer Functions ◽  
Sliding Mode ◽  
Operating Conditions ◽  
Model Parameters ◽  
Feed Water ◽  
Time Varying ◽  
Boiler Unit ◽  
Varying Parameters ◽  
Time Varying Parameters

Stable control of water level of drum is of great importance for economic operation of power plant steam generator systems. In this paper, a linear model of the boiler unit with time varying parameters is used for simulation. Two transfer functions between drum water level (output variable) and feed-water and steam mass rates (input variables) are considered. Variation of model parameters may be arisen from disturbances affecting water level of drum, model uncertainties and parameter mismatch due to the variant operating conditions. To achieve a perfect tracking of the desired drum water level, two sliding mode controllers are designed separately. Results show that the designed controllers result in bounded values of control signals, satisfying the actuators constraints.

A multibody dynamic model for predicting operational load spectra of dual clutch transmissions

2021 ◽  
Vol 263 (2) ◽  
pp. 4132-4143
Author(s):  
Murat Inalpolat ◽  
Enes Timur Ozdemir ◽  
Bahadir Sarikaya ◽  
Hyun Ku Lee
Keyword(s):  
Steady State ◽  
Dynamic Model ◽  
Forced Vibration ◽  
Linear Time ◽  
Vibration Response ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Time Step ◽  
Gear Mesh ◽  
Multibody Dynamic

In this paper, a generalized nonlinear time-varying multibody dynamic model of dual clutch transmissions (DCT) is presented. The model consists of clutches, shafts, gears and synchronizers, and can be used to model any DCT architecture. A nonlinear clutch model is used to determine the transmitted power to the transmission at any speed and clutch temperature. The clutch can be a single- or multi-plate clutch and can operate in a wet or dry-clutch configuration. A combined kinematic and powerflow simulation enables calculation of gear, shaft, bearing and clutch quasi-static loads as well as gear mesh frequencies following a duty cycle as the input. For the corresponding Linear-Time-Invariant (LTI) system model, natural frequencies and mode shapes are obtained by solving the eigenvalue problem. The modal summation technique is used to determine the steady state forced vibration response of the system. For the corresponding NTV system, Newmark's time-step marching based integration is used to determine both the steady state and transient forced vibration response of the system. The DCT model is exercised using a common transmission architecture operating at several different operating conditions. The resulting impact of changing operational conditions on gear and bearing loads as well as dynamic transmission error spectra are demonstrated.

scholarly journals A System Dynamics Model of Fire-Tube Shell Boiler

1994 ◽  
Vol 116 (4) ◽  
pp. 745-754 ◽  
Author(s):  
B. J. Huang ◽  
P. Y. Ko
Keyword(s):  
System Dynamics ◽  
Linear Time ◽  
Estimation Method ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Wide Range ◽  
Perturbed Model ◽  
Tube Shell

A system dynamics model of fire-tube shell boiler was developed. The derivation of the dynamics model started with a nonlinear time-variant dynamic modeling based on the transport phenomena in the fire-tube boiler. A linear time-invariant perturbed model around steady-state operating points was then derived. The identifiable parameters τmw, τwa, K, β, and τd were identified by using field test data and least-squares estimation method; the coefficients C’s were, meanwhile, directly predicted by using the small-perturbation relations. Empirical correlations of the identifiable parameters were further derived to account for the variation of parameters with operating conditions. The present perturbed model is thus semi-empirical and can describe the dynamic behaviour of fire-tube boilers over a wide range of operating conditions. The predictions of dynamic responses using the present model were shown to agree very well with the test results.

scholarly journals Fitting mathematical models of biochemical pathways to steady state perturbation response data without simulating perturbation experiments

2017 ◽  
Author(s):  
Tapesh Santra
Keyword(s):  
Steady State ◽  
Kinetic Models ◽  
Jacobian Matrix ◽  
Molecular Level ◽  
Mitogen Activated Protein Kinase ◽  
Response Analysis ◽  
Model Parameters ◽  
Source Codes ◽  
Mitogen Activated Protein ◽  
Modular Response Analysis

AbstractA common experimental approach for studying signal transduction networks (STNs) is to measure the steady state concentrations of their components following perturbations to individual components. Such data is frequently used to reconstruct topological models of STNs, but, are rarely used for calibrating kinetic models of these networks. This is because, existing calibration algorithms operate by assigning different sets of values to the parameters of the kinetic models, and for each set of values simulating all perturbations performed in the biochemical experiments. This process is highly computation intensive and may be infeasible when molecular level information of the perturbation experiments is unavailable. Here, I propose an algorithm which can calibrate ordinary differential equation (ODE) based kinetic models of STNs using steady-state perturbation responses (SSPRs) without simulating perturbation experiments. The proposed algorithm uses modular response analysis (MRA) to calculate the scaled Jacobian matrix of the ODE model of an STN using SSPR data. The model parameters are then calibrated to fit the scaled Jacobian matrix calculated in the above step. This procedure does not require simulating the perturbation experiments. Therefore, it is significantly less computation intensive than existing algorithms and can be implemented without molecular level knowledge of the mechanism of perturbations. It is also parallelizable, i.e. can explore multiple sets of parameter values simultaneously, and therefore is scalable. The capabilities and shortcomings of the proposed algorithm are demonstrated using both simulated and real perturbation responses of Mitogen Activated Protein Kinase (MAPK) STN.AvailabilityAll source codes and data needed to replicate the results in this manuscript are available from https://github.com/SBIUCD/MRA_SMC_ABC1

Distributed Modeling Of Building Systems Through Cyber-Physical Integration

2019 ◽  
pp. 12-17
Keyword(s):  
Data Structure ◽  
Operating Conditions ◽  
Physical Models ◽  
Distributed Model ◽  
Physical Processes ◽  
Distributed Modeling ◽  
Distributed Models ◽  
Operating Modes ◽  
Building Systems ◽  
Important Practical Application

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

Steady-state Security Assessment Based on K-Means Clustering Algorithm and Phasor Measurement Units

2020 ◽  
Vol 13 (4) ◽  
pp. 559-570
Author(s):  
Bassam A. Hemade ◽  
Hamed A. Ibrahim ◽  
Hossam E.A. Talaat
Keyword(s):  
Steady State ◽  
Clustering Algorithm ◽  
System Security ◽  
Phasor Measurement Units ◽  
Operating Conditions ◽  
Security Assessment ◽  
State Security ◽  
Phasor Measurement ◽  
Measurement Units ◽  
Silhouette Analysis

Background: The security assessment plays a crucial role in the operation of the modern interconnected power system network. Methods: Hence, this paper addresses the application of k-means clustering algorithm equipped with Principal Component Analysis (PCA) and silhouette analysis for the classification of system security states. The proposed technique works on three principal axes; the first stage involves contingency quantification based on developed insecurity indices, the second stage includes dataset preparation to enhance the overall performance of the proposed method using PCA and silhouette analysis, and finally the application of the clustering algorithm over data. Results: The proposed composite insecurity index uses available synchronized measurements from Phasor Measurement Units (PMUs) to assess the development of cascading outages. Considering different operational scenarios and multiple levels of contingencies (up to N-3), Fast Decoupled Power Flow (FDPF) have been used for contingency replications. The developed technique applied to IEEE 14-bus and 57-bus standard test system for steady-state security evaluation. Conclusion: The obtained results ensure the robustness and effectiveness of the established procedure in the assessment of the system security irrespective of the network size or operating conditions.

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