Performance of the Bond Graph Approach for the Detection and Localization of Faults of a Refrigerator Compartment Containing an Ice Quantity

2018 ◽  
Vol 26 (03) ◽  
pp. 1850028 ◽  
Author(s):  
Abderrahmene Sellami ◽  
Emna Aridhi ◽  
Dhia Mzoughi ◽  
Abdelkader Mami
Keyword(s):  
Bond Graph ◽  
Heat Fluxes ◽  
Point Of View ◽  
Internal Cooling ◽  
Linear Fractional Transformations ◽  
Insulation Failure ◽  
Water Container ◽  
Simulation Results ◽  
Heat Transfers ◽  
Detection And Localization

In this paper, a robust fault diagnosis for a refrigerator compartment containing a quantity of ice using the bond graph (BG) approach is performed by linear fractional transformations (LFTs). The BG model describes heat transfers supported by the amount of ice placed in the refrigerator compartment, as well as a water container. The LFT modeling of BG elements offers advantages from the point of view of structural analysis and data processing implementation. We have introduced four faults, which consist of ice temperature rise, water leakage, insulation failure at the hot walls of the refrigerator and an increase of the internal temperature due to poor door sealing. The faults are in the form of additional heat fluxes. The simulation results show the effectiveness of the proposed method for detecting and localizing faults. In addition, the lack of door sealing has the most influence on the temperatures in the internal cooling space, water, and ice compared to the other faults.

scholarly journals Approximation of Linearized Systems to a Class of Nonlinear Systems Based on Dynamic Linearization

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 854
Author(s):  
Raquel S. Rodríguez ◽  
Gilberto Gonzalez Avalos ◽  
Noe Barrera Gallegos ◽  
Gerardo Ayala-Jaimes ◽  
Aaron Padilla Garcia
Keyword(s):  
Nonlinear System ◽  
Nonlinear Systems ◽  
Nonlinear Dynamic ◽  
Bond Graph ◽  
Physical Domain ◽  
Graph Models ◽  
Simple Task ◽  
Analysis And Synthesis ◽  
Simulation Results

An alternative method to analyze a class of nonlinear systems in a bond graph approach is proposed. It is well known that the analysis and synthesis of nonlinear systems is not a simple task. Hence, a first step can be to linearize this nonlinear system on an operation point. A methodology to obtain linearization for consecutive points along a trajectory in the physical domain is proposed. This type of linearization determines a group of linearized systems, which is an approximation close enough to original nonlinear dynamic and in this paper is called dynamic linearization. Dynamic linearization through a lemma and a procedure is established. Therefore, linearized bond graph models can be considered symmetric with respect to nonlinear system models. The proposed methodology is applied to a DC motor as a case study. In order to show the effectiveness of the dynamic linearization, simulation results are shown.

scholarly journals Departamento de Ecología Funcional y Aplicada, Instituto de Ecología, Universidad Nacional Autónoma de México

2017 ◽  
pp. 83
Author(s):  
Victor L. Barradas
Keyword(s):  
Energy Balance ◽  
Control Systems ◽  
Environmental Changes ◽  
Heat Fluxes ◽  
Point Of View ◽  
Net Energy ◽  
Sensible Heat ◽  
Species Establishment ◽  
Physical Barriers ◽  
A Site

<p>The deforestation of a site for agriculture and/ or cattle raising purposes changes either microclimate and soil properties. These environmental changes can act as physical barriers which drastically limits tree species establishment in reforestation . From microclimatic point of view, the study of the energy balance plays a key role when the original environment is severely changed. The net energy in a site is mainly dissipated by latent and sensible heat fluxes which are associated to evapotranspiration and thermal regimes,<br />respectively. The analyses of these fluxes allow to design control systems to reduce the high evaporation rates and high temperatures registered in a deforested site. Energy balance, latent and sensible heat fluxes and other components are analysed, and some techniques to manipulate energy balance are also presented.</p>

The effects of thermal conditions on the cell sizes of two-dimensional convection

1994 ◽  
Vol 281 ◽  
pp. 33-50 ◽  
Author(s):  
Masaki Ishiwatari ◽  
Shin-Ichi Takehiro ◽  
Yoshi-Yuki Hayashi
Keyword(s):  
Heat Flux ◽  
Lower Boundary ◽  
Thermal Conditions ◽  
Heat Fluxes ◽  
Internal Cooling ◽  
Two Dimensional ◽  
Numerical Integrations ◽  
The Difference ◽  
Convective Cells ◽  
Upper Boundary

The effects of thermal conditions on the patterns of two-dimensional Boussinesq convection are studied by numerical integration. The adopted thermal conditions are (i) the heat fluxes through both upper and lower boundaries are fixed, (ii) the same as (i) but with internal cooling, (iii) the temperature on the lower boundary and the heat flux through the upper boundary are fixed, (iv) the same as (iii) but with internal cooling, and (v) the temperatures on both upper and lower boundaries are fixed. The numerical integrations are performed with Ra = 104 and Pr = 1 over the region whose horizontal and vertical lengths are 8 and 1, respectively.The results confirm that convective cells with the larger horizontal sizes tend to form under the conditions where the temperature is not fixed on any boundaries. Regardless of the existence of internal cooling, one pair of cells spreading all over the region forms in the equilibrium states. On the other hand, three pairs of cells form and remain when the temperature on at least one boundary is fixed. The formation of single pairs of cells appearing under the fixed heat flux conditions shows different features with and without internal cooling. The difference emerges as the appearance of a phase change, whose existence can be suggested by the weak nonlinear equation derived by Chapman & Proctor (1980).

Thermostructural Analyses Supporting the Design of the HYPROB Heat Sink Subscale Breadboard

2014 ◽  
Author(s):  
M. Ferraiuolo ◽  
A. Martucci ◽  
F. Battista ◽  
D. Ricci
Keyword(s):  
Heat Sink ◽  
Structural Integrity ◽  
Specific Impulse ◽  
Thermal Analyses ◽  
High Energy ◽  
Life Cycles ◽  
Heat Fluxes ◽  
Point Of View ◽  
Rocket Engines ◽  
Combustion Enthalpy

Today’s rocket engines regeneratively cooled using high energy cryogenic propellants (e.g. LOX and LH2, LOX and LCH4) play a major role due to the high combustion enthalpy (10–13.4 kJ/kg) and the high specific impulse of these propellants. In the frame of the HYPROB/Bread project, whose main goal is to design build and test a 30 kN regeneratively cooled thrust chamber, a breadboard has been conceived in order to: • investigate the behavior of the injector that will be employed in the full scale final demonstrator, • to obtain a first estimate of the heat flux on the combustion chamber for models validation, • to implement a “battleship” chamber for a first verification of the stability of the combustion The breadboard is called HS (Heat Sink) and it is made of CuCrZr (Copper Chromium Zirconium alloy), Inconel 718 and TZM (Titanium Zirconium Molybdenum alloy). The aim of the present paper is to illustrate the thermostructural design conducted on the breadboard by means of a Finite Element Method code taking into account the viscoplastic behavior of the adopted materials. An optimization process has been carried out in order to keep the structural integrity of the breadboard maximizing the life cycles of the component. Heat fluxes generated by combustion gases have been evaluated by means of CFD quick analyses, while convection and radiation with the external environment have not been considered in order to be as conservative as possible from a thermostructural point of view. Transient thermal analyses and static structural analyses have been performed by means of ANSYS code adopting an axisymmetric model of the chamber. These analyses have demonstrated that the Breadboard can withstand the design goal of 3 thermo-mechanical cycles with a safety factor equal to 4 considering a firing time equal to 3 seconds.

Multiple Leakage Detection and Localization Method Based on Bayesian Theory and Genetic Algorithm

2014 ◽  
Vol 635-637 ◽  
pp. 924-927
Author(s):  
Tao Jin ◽  
Ze Yuan Zhou
Keyword(s):  
Genetic Algorithm ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Bayesian Theory ◽  
Leakage Detection ◽  
Localization Method ◽  
Simulation Results ◽  
Detection And Localization ◽  
Leakage Location

To detect and locate the leakage of the pipe correctly, genetic algorithm is combined with Bayesian theory to determine the leaked pipes. Leakage detection and leakage location are carried out separately. Leakage detection is conducted based on the assumption that there is only one leaked pipe, and the simulation result demonstrates its feasibility. When the leakage detection demonstrates there is leaked pipe in the water distribution system, leakage location starts. Based on the information gathered by the manometers, leakage probability in different combinations of the virtual nodal demand can be fixed according to calculating the pressure of the monitored node, then GA is applied to search the maximum Bayesian value, the pipes with maximum Bayesian leakage possibility are believed to be leaked pipes. Optimization programme was made with combination of Matlab and Epanet, numerical simulation results demonstrate the feasibility and effectiveness of the proposed method.

NEW REALIZATIONS OF VOLTAGE-MODE QUADRATURE OSCILLATORS USING CURRENT DIFFERENCING BUFFERED AMPLIFIERS

2010 ◽  
Vol 19 (05) ◽  
pp. 1069-1076 ◽  
Author(s):  
ABHIRUP LAHIRI
Keyword(s):  
Point Of View ◽  
Passive Components ◽  
Voltage Mode ◽  
Sinusoidal Oscillators ◽  
Integration Point ◽  
Condition Of Oscillation ◽  
Simulation Results ◽  
Quadrature Oscillators

A number of sinusoidal oscillators using current differencing buffered amplifiers (CDBAs) have been reported in the literature. However, only three of them are canonic quadrature oscillators (i.e., requiring two capacitors). The aim of this letter is to present additional realizations of single/dual-resistance-controlled quadrature oscillators using CDBAs. Four voltage-mode quadrature oscillators are proposed, which provide the following advantageous features: (i) use of reduced and canonic component count, viz. two CDBAs, three/four resistors and two capacitors, (ii) all passive components are grounded or virtually grounded, which is favorable from integration point of view and (iii) independent and non-interactive resistor control of the condition of oscillation (CO) and the frequency of oscillation (FO). Simulation results verifying the workability of the proposed circuits have been included.

Fault Detection in a Cracked Pipeline Embedded with Piezoelectric Sensors/Actuators Employing Bond Graph Approach

2012 ◽  
Vol 476-478 ◽  
pp. 1015-1019 ◽  
Author(s):  
M. Kolbadi Nejad ◽  
A. Selk Ghafari ◽  
A. Zabihollah
Keyword(s):  
Power Flow ◽  
Active Vibration Control ◽  
Bond Graph ◽  
Piezoelectric Sensors ◽  
Graph Structure ◽  
Sensors And Actuators ◽  
Piezoelectric Sensors And Actuators ◽  
Equivalent Impedance ◽  
Active Vibration ◽  
Simulation Results

The main scope of this article is to simulate a cracked pipeline embedded with piezoelectric sensors and actuators utilizing bond graph approach. Piezoelectric sensors/actuators are becoming very popular in various applications such as health monitoring, active vibration control or noise reduction, and as a part of the systems called smart structures. The proposed bond graph structure in this study, graphically illustrates the power flow between the electrical and mechanical frameworks included in the system. In addition, the proposed framework makes it possible to utilize a modular structure for separately representing the electrical polarization of the material and its macroscopic electrical and mechanical effects. Simulation results illustrate that at the location of the crack the equivalent impedance is increased and the capacitance is decreased in comparison with the intact region.

Numerical investigation of high-pressure turbine blade tip flows: analysis of aerodynamics

2011 ◽  
Vol 225 (7) ◽  
pp. 940-953 ◽  
Author(s):  
P Vass ◽  
T Arts
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Suction Side ◽  
Point Of View ◽  
Internal Cooling ◽  
High Pressure Turbine ◽  
Blade Tip ◽  
Design Solutions ◽  
Exit Mach Number

The current contribution reports on the validation and analysis of three-dimensional computational results of the flow around four distinct high-pressure turbine blade tip geometries (TG1, 2, 3, and 4 hereinafter), taking into account the effect of the entire internal cooling setup inside the blade, at design exit Mach number: M = 0.8, and high exit Reynolds number: Re C = 900 000. Three of the four geometries represent different tip design solutions – TG1: full squealer rim; TG2: single squealer on the suction side; TG3: partial suction and pressure side squealer, and one (TG4) models TG1 in worn condition. This article provides a comparison between the different geometries from the aerodynamic point of view, analyses the losses, and evaluates the distinct design solutions. An assessment of the effect of the uneven rubbing of the blade tip was performed as well. TG1 was found to be the top performer followed by TG3 and TG2. According to the investigations, the effect of rubbing increased the kinetic loss coefficient by 10–15 per cent.

scholarly journals Analytical Solution of Stationary Coupled Thermoelasticity Problem for Inhomogeneous Structures

Mathematics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 90
Author(s):  
Sergey A. Lurie ◽  
Dmitrii B. Volkov-Bogorodskii ◽  
Petr A. Belov
Keyword(s):  
Positive Definiteness ◽  
Heat Fluxes ◽  
Point Of View ◽  
Temperature Fields ◽  
Contact Boundary ◽  
Model Parameters ◽  
Additional Parameter ◽  
Phase Contact ◽  
Inhomogeneous Materials ◽  
Coupled Thermoelasticity

A mathematical statement for the coupled stationary thermoelasticity is given on the basis of a variational approach and the contact boundary problem is formulated to consider inhomogeneous materials. The structure of general representation of the solution from the set of the auxiliary potentials is established. The potentials are analyzed depending on the parameters of the model, taking into account the restrictions associated with additional requirements for the positive definiteness of the potential energy density for the coupled problem in the one-dimensional case. The novelty of this work lies in the fact that it attempts to take into account the effects of higher order coupling between the gradients of the temperature fields and the gradients of the deformation fields. From a mathematical point of view, this leads to a change in the roots of the characteristic equation and affects the structure of the solution. Contact boundary value problems are formulated for modeling inhomogeneous materials and a solution for a layered structure is constructed. The analysis of the influence of the model parameters on the structure of the solution is given. The features of the distribution of mechanical and thermal fields in the region of phase contact with a change in the parameters, which are characteristic only for gradient theories of coupled thermoelasticity and stationary thermal conductivity, are discussed. It is shown, for example, that taking into account the additional parameter of connectivity of gradient fields of deformations and temperatures predicts the appearance of rapidly changing temperature fields and significant localization of heat fluxes in the vicinity of phase contact in inhomogeneous materials.

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