Gibbs Systems Dynamics: A Simple But Powerful Tool for Process Analysis, Design and Optimization

2002 ◽  
Author(s):  
Pierre Neveu ◽  
Nathalie Mazet
Keyword(s):  
Process Analysis ◽  
Irreversible Processes ◽  
Systems Dynamics ◽  
Vapor Compression ◽  
Technical Data ◽  
Design And Optimization ◽  
The Mean ◽  
Analysis Design ◽  
Phenomenological Coefficients ◽  
Condensing Pressure

Dynamic process modeling by the mean of Equivalent Gibbs systems is described here. It allows to model a large number of processes and only requires standard engineering knowledge. This method is issued from thermodynamics of irreversible processes, initiated by I. Prigogine, but applied here to process engineering. First, an Equivalent Gibbs System (EGS) is defined for each component involved in the process. In such system, mass, energy and entropy are linked through Gibbs equation and entropy production can easily be expressed according to fluxes and their related forces. Assuming linear phenomenological laws, phenomenological coefficients can be calculated from common engineering correlations, or evaluated from technical data if available. As an example, a conventional vapor compression chiller is simulated. Three control modes are analyzed on an exergy basis: on/off control with constant or floating condensing pressure, PID control with variable compressor speed.

scholarly journals Using the SWEPT Methodology for a Preliminary Wind Potential Estimation

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Jean-Luc Menet
Keyword(s):  
Wind Turbine ◽  
Characteristic Curve ◽  
Rayleigh Distribution ◽  
Mean Velocity ◽  
Technical Data ◽  
Wind Potential ◽  
Order Of Magnitude ◽  
General Data ◽  
The Mean ◽  
A Site

The implantation of wind turbines generally follows a wind potential study which is made using specific numerical tools; the generated expenses are only acceptable for great projects. The purpose of the present paper is to propose a simplified methodology for the evaluation of the wind potential, following three successive steps for the determination of (i) the mean velocity, either directly or by the use of the most occurrence velocity (MOV); (ii) the velocity distribution coming from the single knowledge of the mean velocity by the use of a Rayleigh distribution and a Davenport-Harris law; (iii) an appropriate approximation of the characteristic curve of the turbine, coming from only two technical data. These last two steps allow calculating directly the electric delivered energy for the considered wind turbine. This methodology, called the SWEPT approach, can be easily implemented in a single worksheet. The results returned by the SWEPT tool are of the same order of magnitude than those given by the classical commercial tools. Moreover, everybody, even a “neophyte,” can use this methodology to obtain a first estimation of the wind potential of a site considering a given wind turbine, on the basis of very few general data.

Modeling time-temperature history and sterilization value of mango puree under conventional and microwave assisted pasteurization

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tamires K. Oishi ◽  
Jorge A. W. Gut
Keyword(s):  
Microwave Heating ◽  
Process Analysis ◽  
Residual Activity ◽  
High Energy ◽  
Temperature History ◽  
Design And Optimization ◽  
Nutritional Characteristics ◽  
Mass Dispersion ◽  
Flow Heat ◽  
Helical Tubes

Abstract Continuous pasteurization of liquid foods has to provide the desired lethality level to guarantee food safety with minimum degradation of quality attributes (sensorial and nutritional characteristics) and high energy efficiency. To optimize quality and cost, a thermal process should be modeled considering flow, heat transfer and mass dispersion principles; however, flow through helical tubes and microwave heating require a complex 3D multiphysics approach. Herein a simplified 2D approach is presented to model a hybrid pasteurization unit with conventional and microwave heating under laminar flow to predict axial and radial distributions of temperature and residual activity of a microorganism or enzyme. A study case of 20 °Brix mango puree (power law fluid) processing is used to test the model based on an existing pilot plant unit. Results were useful to compare conventional and microwave heating regarding the process sterilization value and model can be used for process analysis, design and optimization.

scholarly journals The Development and Validation of a Module on Enhancing Students' Critical Thinking, Collaboration and Writing Skills

2020 ◽  
pp. 166-177
Author(s):  
Moustafa Mohamed Abdelmohsen
Keyword(s):  
Critical Thinking ◽  
Writing Skills ◽  
Design Development ◽  
Validity And Reliability ◽  
Paired Samples ◽  
Foundation Program ◽  
The Mean ◽  
Analysis Design ◽  
Addie Model ◽  
Development And Validation

This study aims to develop and test the validity of a module on enhancing students' collaboration, critical thinking (2Cs) and writing skills. To develop the module, the researcher used ADDIE model which incorporates five primary phases, namely Analysis, Design, Development, Implementation and Evaluation. The study used a tryout group which incorporated 20 participants who studied English at The General Foundation Program at a private college in Oman. The study employed a pretest-posttest quasiexperimental design. Paired Samples t-Test was used to compare the mean scores of both tests. Apropos of module validity, a total of 5 experts validated the module. The findings revealed that there is a statistically significant mean difference between the participants' scores in both the pretest and posttest. Further, it was found that the module has good validity and reliability.

Analysis, Design, and Optimization of Thermal In-Plane Microactuator—Chevron Type

2011 ◽  
Vol 8 (3) ◽  
pp. 102-109
Author(s):  
K.B. Puneeth ◽  
K.N. Seetharamu
Keyword(s):  
Neural Network ◽  
Mechanical Response ◽  
Thermal Response ◽  
Structural Response ◽  
Design Tool ◽  
Thermal Actuator ◽  
Coupled Models ◽  
Element Analysis ◽  
Design And Optimization ◽  
Analysis Design

A predictive model of thermal actuator behavior has been developed and validated that can be used as a design tool to customize the performance of an actuator to a specific application. Modeling thermal actuator behavior requires the use of two sequentially or directly coupled models, the first to predict the temperature increase of the actuator due to the applied voltage and the second to model the mechanical response of the structure due to the increase in temperature. These models have been developed using ANSYS for both thermal response and structural response. Consolidation of FEA (finite element analysis) results has been carried out using an ANN (artificial neural network) in MATLAB. It is seen that an ANN can be successfully employed to interpolate and predict FEA results, thus avoiding necessity of running FEA code for every new case. Furtheroptimization of geometry for maximum actuation length has been carried out using a GA (genetic algorithm) in MATLAB. The results of the GA were verified against the ANN and FEA results.

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