scholarly journals Causality in Models of Thermal Processes in Ship Engine Rooms with the Use of Bond Graph (BG) Method

2017 ◽  
Vol 24 (s1) ◽  
pp. 32-37 ◽  
Author(s):  
Marian Cichy ◽  
Zbigniew Kneba ◽  
Jacek Kropiwnicki

AbstractWith a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented [2] new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality in models of thermal processes created by the said concept were given. The analysis of causality makes it possible to demonstrate the model conflicts that prevent the placement of state equations which allows for the direct conduct of simulation experiments. Attention has been drawn to the link between the energy systems models of thermal processes with models of elements of different physical nature. Two examples of determining causality in models of complex energy systems of thermal elements have been presented. The firs relates to the electrical system associated with the process of heat exchange. The second is a model of the mechanical system associated with the thermodynamic process.

Author(s):  
Darina Hroncová

Urgency of the research. The bond graphs theory aim for to formulate general class physical systems over power interactions. The factors of power are effort and flow. They have different interpretations in different physical domains. Yet, power can always be used as a generalized resource to model coupled systems residing in several energy domains. Target setting. Formalism of power graphs enables to describe different physical systems and their interactions in a uniform, algorithmizable way and transform them into state space description. This is useful when analyzing mechatronic systems transforming various forms of energy (electrical, fluid, mechanical) by means of information signals to the resulting mechanical energy. Actual scientific researches and issues analysis. Over the past two decades the theory of Bond Graphs has been paying attention to universities around the world, and bond graphs have been part of study programs at an ever-increasing number of universities. In the last decade, their industrial use is becoming increasingly important. The Bond Graphs method was introduced by Henry M. Paynter (1923-2002), a professor at MIT & UT Austin, who started publishing his works since 1959 and gradually worked out the terminology and formalism known today as Bond Graphs translated as binding graphs or performance graphs. Uninvestigated parts of general matters defining. The electrical system model is solved with the help of the above mentioned bond graphs formalism. Gradually, the theory of power graphs in the above example is explained up to the construction of state equations of the electrical system. The state equations are then solved in Matlab / Simulink. The statement of basic materials. Using bond graphs theory to simulate electrical system and verify its suitability for simulating electrical models. In various versions of the parameters of model we can monitor its behavior under different operating conditions. The language of bond graphs aspires to express general class physical systems through power interactions. The factors of power i.e., effort and flow, have different interpretations in different physical domains. Yet, power can always be used as a generalized coordinate to model coupled systems residing in several energy domains. Conclusions. We introduced a method of systematically constructing a bond graph of an electrical system model using Bond graphs. A practical example of an electrical model is given as an application of this methodology. Causal analysis also provides information about the correctness of the model. Differential equations describing the dynamics of the system in terms of system states were derived from a simple electrical system coupling graph. The results correspond to the equations obtained by the classical manual method, where first the equations for individual components are created and then a simulation scheme is derived based on them. The presented methodology uses the reverse procedure. However, manually deriving equations for more complex systems is not so simple. Bond charts prove to be a suitable means of analysis, among other systems and electrical systems.


2021 ◽  
Vol 35 ◽  
pp. 100657
Author(s):  
Sofia G. Simoes ◽  
Filipa Amorim ◽  
Gildas Siggini ◽  
Valentina Sessa ◽  
Yves-Marie Saint-Drenan ◽  
...  

2021 ◽  
Vol 2061 (1) ◽  
pp. 012131
Author(s):  
O N Litskevich ◽  
A P Litskevich

Abstract This article solves the problem of a quantitative assessment of the occurrence of destruction in the intersystem interactions of the transport system and the electrical system of the seaport, in the conditions of the technological process in the seaport, which indicates its significant impact on the electrical system, as a result of which the reliability of the berthing power line is significantly reduced. The intersystem interactions that occur during the implementation of the technological process, as experience shows, are the causes of critical situations that occur at the border of areas of different physical nature, and the consequences are recorded, in the case under consideration, in the electrical system. A mathematical model describing intersystem destruction in quantitative form is presented in this paper using a logical-probabilistic model that reflects internal and external relationships. In the object under study, the destructive cause (collision) and the consequence (accumulation of electrical damage in the insulation of the cable line) are in the same object (the mooring power supply unit), and this is limited to the effects of intersystem destruction. In such a statement, the object of power supply of the technological process and equipment is considered as a composite object containing a cable line and an electric contact column. The problem being formulated is an important and relevant scientific task, which includes not only the question of identifying the causes of increased electrical wear of the power line, but also the development of methods for obtaining quantitative results, and in practical terms also involves the diagnosis of the technical condition of electrical equipment and timely preventive maintenance.


Author(s):  
S. Rech ◽  
A. Lazzaretto

A common approach for simulation of energy systems at design and off-design conditions is presented, which uses the same concepts and terminology independently of system dimension, complexity and detail. The paper shows that the higher the dimension of the system, the simpler is the model of each part of the system, but concepts and approach to built the model remain the same, being those commonly used in the literature. The approach consists in organizing energy systems models according to some criteria, which help enhance system models comprehension, and build them more easily. For any dimension and level of detail of the system these criteria consist in identifying the design specification from the environment surrounding the system, choosing the independent variables depending on the nature of the model, organizing them into categories, defining performance curves (characteristic maps) of each part of the system and organizing mass and energy balances into categories. Particular emphasis is given on modeling of system units behavior, which is generally described by the mathematical functions (characteristic maps) linking outflow to inflow variables. Examples of characteristic maps of the system units at each level of detail are shown, and models are then completed by mass, energy and momentum balances linking the behavior of all system units.


Author(s):  
Majid Habibi ◽  
Alireza B. Novinzadeh

Satellite state control has always been an important topic in aerospace technology. Because it is required that when the satellite is stationary in orbit, it would be directed to a special object and this task should be performed in a situation where there isn’t access to the satellite. This task is performed using various technologies and one of these is the use of magnetic actuators. Magnetic actuators use mechanical torque that is resulted by interaction of electrical current of coils in the satellite and the earth’s magnetic field. The satellite is subjected to such disturbance torques, thus corrupting the direction of the satellite. This method has its advantages and disadvantages. Its drawback is that the magnetic torque is produced only perpendicular to the direction of the magnetic field and the axis of the coil. This paper models a satellite having magnetic actuators using bond graph, and finds out its state equations, and then constructs the control logic that is needed for its control. A model of three dimensional attitude maneuvers and magnetic systems using bond graph is described. The actuators are tuned using the method of particle swarm optimization (PSO). It is observed that using this method a small satellite reaches to the desired angle in a short time and becomes stationary.


2000 ◽  
Vol 122 (3) ◽  
pp. 461-469 ◽  
Author(s):  
Jongbaeg Kim ◽  
Michael D. Bryant

An existing bond graph of a squirrel cage induction motor was modified to make the bond graph physically more representative. The intent was to form a one-to-one correspondence between motor components and bond graph elements. Components explicitly represented include the stator coils, the squirrel cage rotor bars, and the magnetic flux routing section. The final bond graph spans electrical, magnetic, and mechanical energy domains, and contains common motor faults. From this bond graph. state equations were extracted and simulations performed. Simulated were the response of healthy motors, and motors with shorted stator coils and broken rotor bars. [S0022-0434(00)01203-X]


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