Method of thermodynamic functions for the research of the Magnetic Suspension and Balance System for wind tunnel aircraft models

Аuthors

Vyshkov Y. D.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: yuvyshkov@mail.ru

Abstract

The paper considers the application of the thermodynamic functions method for the research of the Magnetic Suspension and Balance Systems (MSBS) for wind tunnel models with six degrees of freedom.
Electromagnetic suspension system includes subsystems of different physical nature — electrical and mechanical.
Interdependencies and interaction between mechanical and electrical variables in the electromechanical systems are defined by the equations of mechanics and electromagnetic field. The difficulty of establishing relationships between the variables on the basis of these equations is conditioned by the fact that the electromagnetic characteristics of the materials (magnetic permeability and dielectric permittivity, conductivity), which are included in the equations, depend on the energy density in the matter. It is also necessary to note that these dependencies are not amenable to theoretical calculation while the experimental characteristics can only be obtained in the simplest cases (which are quite far from the considered Magnetic Suspension and Balance System for wind tunnel). Complexity of the configuration of the electromagnetic system of a real Magnetic Suspension and Balance System for wind tunnel aircraft models also leads to serious mathematical complexities in obtaining the equation solutions.
In this paper, the relationships between mechanical and electrical variables are established on the basis of the general energy principles. This allowed to establish a number of new common relationships between the state variables and functions of the energy state of the electromechanical systems, and, in particular, for the suspension system for wind tunnel aircraft models.
The method of analysis of electromechanical systems, which is also called the «method of the energy state functions», is based on the energy conservation law. This law is expressed in the form of differential input functions, which describe the energy state of the electromechanical systems. The general relations between the changes of the state variables and the energy functions values are established based on the condition of existence of the total differentials of these energy functions.
The developed method was used to create a model of the electromagnetic suspension system for wind tunnel aircraft models. There are n electromagnetic forces in this electromagnetic suspension system, which are applied to the aircraft model with six variable spatial coordinates.
The relations, which were derived from the developed method, allow us to express some system characteristics in terms of the others. This result can be used during the design and study of the electromagnetic suspension system. The adduced research helps to deal with the fact that while the electromagnetic force depends on the current values of the spatial coordinates, which are available for measurement, the measurement of the magnetic flux is very difficult. This is especially true for the multicomponent electromagnetic suspension with several electromagnets, which are situated in the magnetic field with a complex configuration such as the one that exists in the suspension system for wind tunnel aircraft models.

Keywords:

wind tunnel , magnetic suspension, wind tunnel aircraft model, method of thermodynamic functions

References

1. Vyshkov Ju.D., Kovalnogov S.A., Usachev V.N., Shapovalov G.K. Uchenye zapiski CAGI, 1986, vol. XVII, no. 4, pp. 94-97.
2. Sivuchin D.V. Termodinamika i molekularnaya phizika (Thermodynamics and molecular physics), Мoscow, Nauka, 1978, 552 p.
3. Lenk A. Elektromechanicheskye sistemy (Electromechanical systems), Moscow, Мir, 1978, 285 p.

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