Use of three-stage decomposition method for simulation of spacecraft thermal control subsystem

Аuthors

Pavlov D. V.^*, Petrov D. S.^**

*e-mail: dmitripavlov@inbox.ru
**e-mail: dmitry.s.petrov@engineer.com

Abstract

The article is devoted to simulation of a spacecraft thermal control system with the use of new simulation paradigm. The paradigm is based on three-stage decomposition method, which has been proposed by the authors. The thermal control system under consideration follows the same principles as the on-board systems of real spacecraft like Soyuz TMA-M and Progress-M.

At the first stage the hierarchical decomposition is made according to the spacecraft dividing circuit. As a result, the system is divided into parts, which models are named components. Components are nested into each other and establish a hierarchy similar to the dividing circuit.

At the second stage the interface decomposition is made when interface entities are picked out in every component prototype. Models of such entities are named simple models (SM).

At the third stage the interactional decomposition is made when each SM prototype is considered as a member of various physical interactions. Each SM is composed of set of fragments that represent the SM prototype involvement in interaction of specific physical domain. Each fragment is an object that contains the SM prototype parameters related to the physical domain. Additionally, the number of subroutines is assigned to each fragment that calculates relations between the parameters.

While modeling the various links between parameters of different fragments of the same SM are taken into account. That links are named cross-fragment links and implemented with particular subroutines each of which corresponds to the unique fragments combination.

Simulation model structure is defined with particular objects bonds. Each bond joins two SMs. Bonds declare copying of parameters between fragments of linked SMs.

In this paper the creation of universal standard elements library is considered. The library includes, firstly, the fragment classes definition, which are used for simulation of fluid flow through spacecraft subsystem pipelines, secondly, subroutines for simulation of relationship between heat and hydrodynamic domains, thirdly, bond definition, and, finally, the description of component classes used for spacecraft thermal control subsystem simulation.

The main feature of the library is a wide use of cross- fragment links that makes the flexibility of designed fragments possible. For instance, any pipeline for gas flow including heat transfer as well as for liquid isothermal flow is simulated with the use of the same fragments that define pipeline geometric properties. The flow of particular substances is simulated using, firstly, special fragments that define substance properties and, secondly, cross-fragment links between fragments of hydrodynamic, thermal and substantial physical domains.

By means of this library the simulation model of a spacecraft thermal control system was designed. The results of the typical processes of simulation have been obtained; the conclusion about the correspondence of the calculations results to the real spaceship telemetry data has been made.

The library can be used for simulation of real spacecraft thermal control system with a similar design and operating principle. The library may also be expanded for simulation of various flow processes of different substances of various states, what allows to simulate another spacecraft onboard subsystems like life support system.

Keywords:

simulation, spacecraft, thermal control system, three-stage decomposition

References

1. Belova V.V. Vestnik FGUP «NPO im. S.A. Lavochkina», 2012, no. 1, pp. 50–58.
2. Duboshin G.N. Spravochnoe rukovodstvo po nebesnoi mekhanike i astrodinamike (Guide on celestial mechanics and astrodynamics), Moscow, Nauka, 1976, 889 p.
3. Gerts E. V., Kreinin G. V. Raschet pnevmoprivodov (Handbook for pneumatic devices calculation), Moscow, Mashinostroenie, 1975, 272 p.
4. Landau L.D., Lifshits E.M. Teoreticheskaya fizika (Course of theoretical physics), Moscow, Nauka, 1986, vol. VI, 736 p.
5. Mukherjee A., Karmakar R. Modelling and simulation of engineering systems through bondgraphs, Pangbourne, UK, Alpha Science Int’l Ltd., 2000, 470 p.
6. Mukherjee A., Samantaray A. K. Bond graph in modeling, simulation and fault identification, New Delhi, India, I.K. International Pvt. Ltd., 2006, 512 p.
7. Paynter H. Analysis and design of engineering systems, Cambridge, Massachusetts, M.I.T. press, 1961, 303 p.
8. Petrov D. S. Vestnik Moskovskogo Aviatsionnogo Instituta, 2014, vol. 21, no. 1, pp. 43–57.
9. Petrov D. S. Materialy konferentsii «Upravlenie v morskikh i aerokosmicheskikh sistemakh» (UMAS-2014), St. Petersburg, 2014, pp. 583–590.
10. Shcherbina O. A. Kratkoe vvedenie v AMPL-sovremennyi algebraicheskii yazyk modelirovaniya, 2012, available at: http://soa7.socionet.ru/files/AMPL.pdf, 29p.
11. Solov’ev V. A., Lysenko L. N.,, Lyubinskii V. E. Upravlenie kosmicheskimi poletami (Space mission control), Moscow, MGTU im. N. E. Baumana, 2009, 902 p.