Simplified method for thermal mode computing of a panel-type refrigerator-radiator

Аuthors

Cherkasov S. G.^*, Laptev I. V.^**

Keldysh Research Centre, 8, Onezhskaya str., Moscow, 125438, Russia

*e-mail: sgcherkasov@yandex.ru
**e-mail: laptev@kerc.msk.ru

Abstract

The authors proposes a simplified method for stationary thermal mode computing of a panel-type refrigerator-radiator with account for longitudinal and lateral temperature non-uniformities in the coolant tube and radiating fins and corresponding non-uniformities in radiant heat flux distribution. A typical panel-type refrigerator-radiator in the form of curved coolant tube with radiating fins, through which a gas or liquid coolant is forcibly pumped, is represented as a straight-line tube with fins uniformly fixed by angle. While moving through the tube, the coolant releases heat into surrounding structure, from where this heat radiates to the outer space. The coolant temperature at the outlet of the panel-type refrigerator is less than at the inlet, and this temperature difference determines the integral radiated heat flux. A heat exchange coefficient was introduced for accounting for the heat exchange process between the coolant and the tube wall. This coefficient is a user-defined parameter of the problem. The conjugation condition of thermal flux and temperature at the tube and fin coupling point, and the coolant thermal balance considering allow reduce this problem to an ordinary differential equation, describing temperature changing dynamics of the coolant along the tube. The proposed method may be employed for determining the linear size of panel-type refrigerator-radiator with specified characteristics and requirements on thermal power dumping. The performed computations of panel-type refrigerator-radiator thermal mode of the prospective spacecraft with nuclear power plant onboard demonstrated the workability of the proposed method. It was demonstrated, that temperature differences in the wall material were insignificant, and the main temperature non-uniformities are realized at the fin. The temperature deviation at the place of the tube and fin coupling from the coolant temperature in every section are insignificant either, which confirms the linearization validity. The impact of various approximations while estimation of the state of the panel-type refrigerator-radiator was considered. It was demonstrated, that simplified calculations with no accounting for temperature non-uniformities inside the structure of the panel-type refrigerator-radiator might lead to significant errors in determining the structure sizes.

Keywords:

plane radiator, coolant, temperature non-uniformity, heat radiation, cooling fin

References

1. Favorskij O.N., Kadaner Ya.S. Voprosy teploobmena v kosmose [The problems of heat exchange in space]. Moscow, Vysshaya shkola, 1967. 240 p. In Russ.

2. Rojzen L.I., Dul’kin I.N. Teplovoj raschet orebrennykh poverkhnostej. Pod red. V.G. Fastovskogo [Thermal calculation of finned surfaces, ed. by V.G. Fastovsky.]. Moscow, Energiya, 1977. 256 p. In Russ.

3. Samarskij А.А., Vabishhevich P.N. Vychislitel’naya teploperedacha [Computational heat transfer]. Moscow, Editorial URSS, 2003. 784 p. In Russ.

4. Cherkasov S.G. Asymptotic solutions in the problem of a heat-conducting radiating rib. High Temperature, 2011, vol. 49, no. 6, pp. 924–926.

5. Cherkasov S.G., Laptev I.V. Approximate analytical solution of a 2D problem for a heat conducting emitting plate. High Temperature, 2017, vol. 55, no. 1, pp. 75–78.

6. Formalev V.F., Reviznikov D.L. Chislennye metody [Numerical methods]. Moscow, FIZMАTLIT, 2004. 400 p. In Russ.

7. Ferziger J.H., Peric M. Computational methods for fluid dynamics. Springer, 2002. 423 p.

8. Jansen F., Bauer W., Masson F., Ruault J.-M., Worms J.-C., Detsis E., Lassoudiere F., Granjon R., Gaia E., Ferraris S., Tosi M.C., Koroteev A.S., Semenkin A.V., Solodukhin A., Tinsley T., Hodgson Z., Guimaraes L.N.F. Step-by-step realization of the international nuclear power and propulsion system (INPPS) mission. Proceedings of 66th International Astronautical Congress 2015 (IAC 2015): Space – The Gateway for Mankind’s Future, IAF, 2015, pp. 7716–7724.

9. Koroteev А.S., Oshev Yu.А., Popov S.А., Karevskij А.V., Solodukhin А.E., Zakharenkov L.E., Semenkin А.V. Yadernaya ehnergodvigatel’naya ustanovka kosmicheskogo apparata [The nuclear power propulsion system for the spacecraft] Izvestiya Rossijskoj akademii nauk. Energetika – Proceedings of the Russian Academy of Sciences. Power Engineerin . 2015, no. 5,. pp. 45–59. In Russ.

10. Koroteev A.S., Oshev Y.A., Popov S.A., Karevsky A.V., Solodukhin A.Y., Zakharenkov L.E., Semenkin A.V. Nuclear power propulsion system for spacecraft. Thermal Engineering, 2015, vol. 62, no. 13, pp. 971–980.