Choosing an optimal temperature for the current converter in a space power plant

The perspective energy conversion systems of space power plants are considered to be based on using thermionic plasma valves such as grid key elements, high-voltage plasma thermionic diodes, and high-temperature semiconductor valves. The application of such valves can increase the efficiency of electrical propulsion systems for space due to their high operating temperature (T = 700 ... 1 000 K). However, the performance of valves decreases with increasing temperature, and the voltage drop in a conductive state affects the effectiveness of the valves and the energy conversion system as a whole. Therefore, the definition of an optimal temperature corresponding to the maximum efficiency of the current converter in a space power plant is very important for designing new space propulsion systems. This paper is the first to model energy and mass characteristics of energy conversion systems at elevated temperatures up to 800 K. It is suggested that electrical propulsion systems for space should use high-temperature valves, which would reduce the specific mass of the current converter. A relation between the output voltage of the current converter and its electrical power and temperature is established. It is found that one of the promising ways of developing high-temperature energy conversion systems is to use grid key elements and high-voltage plasma thermionic diodes as they provide the required voltage of 1 000 ... 2 500 V at temperatures up to 1 000 K. The results of research can be useful when designing new high-temperature space energy conversion systems for space electric power plants with a capacity of hundreds of kilowatts.

References

[1] Troitskii S.R., Bystrov P.I., Barannikov A.L. Issledovanie i eksperimental’naia otrabotka vysokotemperaturnykh agregatov sistem elektrosnabzheniia iadernoi energeticheskoi ustanovki s termoemissionnym reaktorom-preobrazovatelem [Research and experimental development of high-temperature units power supply systems of nuclear power plant thermionic converter reactor]. Raketno-kosmicheskie dvigateli i energeticheskie ustanovki. Sistemy i sredstva bortovoi energetiki [Space rocket engines and power plants. Systems and facilities onboard energy]. Moscow, NIITP publ., 1993, pt. 2, pp. 106–113.

[2] Onufriev V.V., Marakhtanov M.K., Grishin S.D., Siniavskii V.V. Vybor parametrov system preobrazovaniia toka v kosmicheskikh IaEU bol’shoi moshchnosti [Selection of parameters conversion systems current space NPS high power]. Atomnaia energiia [Atomic Energy]. 2000, vol. 89, issue 1, pp. 78–81.

[3] Onufriev V.V., Marakhtanov M.K., Grishin S.D., Siniavskii V.V. Problemy vybora parametrov sistem preobrazovaniia toka v kosmicheskikh iadernykh energeticheskikh ustanovkakh bol’shoi moshchnosti [The problem of choosing the parameters of systems converting the current to space nuclear power plants of high power]. Kosmicheskaia energetika 21 veka: Tezisy dokladov 2-go Mezhdunarodnogo seminara [Cosmic Energy XXI century: Abstracts 2nd International Workshop]. Obninsk, 2000, pp. 68–69.

[4] Onufriev V.V., Marakhtanov M.K., Siniavskii V.V., Muboiadzhian S.A. O massoenergeticheskikh preimushchestvakh vysokotemperaturnoi elektroraketnoi dvigatel’noi ustanovki [The massenergy advantures of high temperature electrical power propulsion system]. Izvestiia RAN. Energetika [Journal of the Russian Academy of Sciences. Energy]. 2003, no. 3, pp. 53–59.

[5] Onufriev V.V., Marakhtanov M.K., Siniavskii V.V., Muboiadzhian S.A. O vybore optimal’nykh parametrov silovoi kabel’noi seti elektroraketnoi dvigatel’noi ustanovki s nizkovol’tnym istochnikom toka [Characteristics of high cable network electric propulsion system with low-voltage current source]. Izvestiia RAN. Energetika [Journal of the Russian Academy of Sciences. Energy]. 2003, no. 4, pp. 71–77.

[6] Onufriev V.V., Marakhtanov M.K., Grishin S.D., Siniavskii V.V. Parametricheskaia optimizatsiia sistem preobrazovaniia toka IaERDU bol’shoi moshchnosti (rezul’taty raschetnykh i eksperimental’nykh issledovanii ) [Parametric optimization of current conversion YAERDU high power (results calculated and experimental studies)]. Kosmos bez oruzhiia — arena mirnogo sotrudnichestva v 21 veke: Tezisy doklada mezhdunarodnoi konferentsii [Space without weapons — the arena of peaceful cooperation in the twenty-first century: Proceedings of International Conference]. Moscow, 2001, pp. 141–142.

[7] Onufriev V.V., Marakhtanov M.K., Muboiadzhian S.A., Siniavskii V.V. O vybore optimal’nogo temperaturnogo rezhima kosmicheskikh iadernykh elektroraketnykh dvigatel’nykh ustanovok (IaERDU) [On the choice of optimal temperature space nuclear electric propulsion systems (YAERDU)]. Nauchnaia sessiia MIFI-2001: Tezisy doklada [Scientific session of the MIFI-2001: Abstracts]. Moscow, 2001, vol. 8, pp. 95–96.

[8] Onufrieva E.V., Onufriev V.V., Iaminskii V.V. Razrabotka vysokovol’tnykh plazmennykh termoemissionnykh diodov vysokotemperaturnogo preobrazovatelia toka energodvigatel’nykh ustanovok [Development of high plasma thermionic diodes high-current converter power and propulsion]. Vestnik MGTU im. N.E. Baumana. Ser. Mashinostroenie [Herald of the Bauman Moscow State Technical University. Mechanical Engineering]. 2011, special issue «Ionnoplazmennye tekhnologii», pp. 70–73.

[9] Onufriev V.V., Onufrieva E.V., Siniavskii V.V. Vysokotemperaturnye sistemy preobrazovaniia toka perspektivnykh kosmicheskikh energodvigatel’nykh ustanovok [High power conversion system prospective space power and propulsion]. Izvestiia RAN. Energetika [Journal of the Russian Academy of Sciences. Energy]. 2009, no. 4, pp. 137–144.

[10] Loshkarev A.I., Onufriev V.V., Siniavskii V.V. Elektroenergeticheskie kharakteristiki termoemissionnogo vysokovol’tnogo dioda dlia kosmicheskikh energodvigatel’nykh ustanovok [Electric-energy characteristics of the thermion high voltage diode for the Space energypropulsion module]. Izvestiia RAN. Energetika [Journal of the Russian Academy of Sciences. Energy]. 2006, no. 1, pp. 87–97.

[11] Kankam M.D., Ribeiro P.F. Energy Loss Analysis of an Integrated Space Power Distribution System. 27th International Energy Conversion Engineering Conference: Proceeding, San Diego (CA), 1994, vol. 2, pp. 189–194.

[12] El-Genk M.S., Kaibyshev V.Z., Murray C. Effect of the Grid Aperture on the Operation of the Cs-Ba Tasitron Inverter. 27th International Energy Conversion Engineering Conference: Proceeding, San Diego (CA), 1994, vol. 2, pp. 343–347.

[13] Onufriev V.V., Siniavskii V.V. Rezul’taty eksperimental’nogo issledovaniia vysokovol’tnogo termoemissionnogo ventilia s teplovym upravleniem [The results of the experimental investigation of the high volt age thermionic switch with heat control]. Izvestiia RAN. Energetika [Journal of the Russian Academy of Sciences. Energy]. 2009, no. 1, pp. 36–42.

[14] Onufriyev V.V. The Results of Investigations of High Temperature High Voltage Thermion Diode. International Energy Conversion Engineering Conference. (IECEC 2000): Proceeding, Las Vegas (NV), 2000, pp. 290–296.

[15] Onufriyev V.V. Experimental Investigation of High Temperature High Voltage Thermionic Diode for the Space Power Nuclear Reactor. Space Technology and Applications International Forum (STAIF-2001): Proceeding, Albuquerque (NM), 2001, pp. 1136–1141.

[16] Onufriev V.V. Sposob vypriamleniia peremennogo toka i ustroistvo dlia ego osushchestvleniia [Method of rectifying the AC current and device for its realization]. Patent RF no. 2111605, 1998.

[17] Onufriev V.V. Sposob vkliucheniia plazmennogo tiristora i ustroistvo dlia ego osushchestvleniia [Way to turn the Plasma thyristor and device for its implementation]. Patent RF no. 2144716, 2000.

[18] Onufriev V.V., Siniavskii V.V. Termoemissionnyi ventil’ sistemy vypriamleniia toka kosmicheskoi energoustanovki [Thermionic valve system rectification space power plant]. Patent RF no. 2195740, 2002.