The Efficiency of Closed-Cycle Gas Turbines Controlled by Different Methods and Programs

Closed-cycle gas turbine units can be used as power plants for advanced nuclear power stations, spacecraft, ground, surface and underwater vehicles. The purpose and power capacity of closed gas turbine units (CGTU) determine their specific design schemes, taking into account efficient operation of the units both in the nominal (design) mode and in partial power modes. Control methods of both closed and open gas turbine units depend on the scheme and design of the installation but the former differ from the latter mainly in their ability to change gas pressure at the entrance to the low-pressure compressor. This pressure can be changed by controlling the mass circulating in the CGTU circuit, adding or releasing part of the working fluid from the closed system as well as by internal bypassing of the working fluid. At a constant circulating mass in the single-shaft CGTU, the temperature of the gas before the turbines and the shaft speed can be adjusted depending on the type of load. The rotational speed of the turbine shaft, blocked with the compressor, can be adjusted in specific ways, such as changing the cross sections of the flow of the impellers. At a constant mass of the working fluid, the pressure at the entrance to the low-pressure compressor varies depending on the control program. The efficiency of the CGTU in partial power modes depends on the installation scheme, control method and program. The most economical control method is changing the pressure in the circuit. Extraction of the working fluid into special receivers while maintaining the same temperature in all sections of the unit leads to a proportional decrease in the density of the working fluid in all sections and the preservation of gas-dynamic similarity in the nodes (compressors, turbines and pipelines). Specific heat flux rates, and therefore, temperatures change slightly in heat exchangers. As the density decreases, heat fluxes change, as the heat transfer coefficient decreases more slowly than the density of the working fluid. With a decrease in power, this leads to a slight increase in the degree of regeneration and cooling in the heat exchangers. The underestimation of these phenomena in the calculations can be compensated by the underestimation of the growth of losses in partial power modes.

References

[1] Arbekov A.N., Ivanov V.L., Manushin E.A., Mikhal’tsev V.E., Molyakov V.D., Osipov M.I., Surovtsev I.G., Troitskiy N.I. Teoriya i proyektirovaniye gazoturbinnykh i kombinirovannykh ustanovok [Theory and design of gas turbine and combined installations.]. Moscow, Bauman Press, 2017. 678 p.

[2] Molyakov V.D., Osipov M.I., Syromyatnikova L.I., Tumashev R.Z. Calculation Method and Operation Mode Analysis of Multishaft Gas Turbine Engines with Modernized Cycles. Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, 2008, no. 4(73), pp. 3–24 (in Russ.).

[3] Loshchakov I.I., Romakhova G.A., Komolov I.A. Modelirovaniye gazoturbinnoy ustanovki dlya raboty na gelii [Modeling a gas turbine installation for working on helium]. Available at: http://www.pmz.ru/upload/pages/5914/sbornik_111-115.pdf (accessed 15 September 2019).

[4] Khrustalev V.A., Naumov A.S. Issues of combining schemes of gas turbines and nuclear power plants and their effectiveness. Vestnik SGTU, 2011, no. 1(54), iss. 3, pp. 142–149 (in Russ.).

[5] Babayev I.N. Upgrading the Control Systems of Turbines of K-160-12.8 Type Produced by PAO Turboatom. Thermal Engineering, 2018, no. 5, pp. 59–64 (in Russ.).

[6] Bilenko V.A., Zhigunov V.V. Comparative Analysis of the Dynamic Properties of Variants of Automatic Frequency and Power Control Systems for Steam Power Plants Equipped with Once-Through Boilers. Thermal Engineering, 2018, no. 4, pp. 5–20 (in Russ.).

[7] Ucharova A.U., Marchenko G.I., Druzhinin G.I., Petrushenko Yu.Ya. Features of work of gasturbine installations of the closed cycle on variable modes. Izvestiya vysshikh uchebnykh zavedeniy. Problemy energetiki, 2009, no. 1–2, pp. 92–96 (in Russ.).

[8] Hervol D.S., Briggs M., Owen А.К., Lavelle Т.A. Experimental and analytical performance of a Dual Brayton Power Conversion System. 6th International Energy Conversion Engineering Conference, 2008, no. 2008-5735.

[9] Manushin E.A., Beknev B.C., Osipov M.I., Surovtsev I.G. Yadernyye gazoturbinnyye i kombinirovannyye ustanovki [Nuclear gas turbine and combined installations]. Moscow, Energoatomizdat publ., 1993. 272 p.

[10] Ivanov V.L., Leont’yev A.I., Manushin E.A., Osipov M.I. Teploobmennyye apparaty i sistemy okhlazhdeniya gazoturbinnykh i kombinirovannykh ustanovok [Heat exchangers and cooling systems for gas turbine and combined installations]. Moscow, Bauman Press, 2004. 592 p.

[11] Efimov N.N., Shestachenko I.Ya., Povetkin V.G. Optimization processes and problems of regulation of gas turbine power plants. University news. North-Caucasian region. Technical sciences series, 2005, no. 1, pp. 39–41 (in Russ.).

[12] Sultanov R.F., Senyushkin N.S. Cycle main parameter effect on promising gtp performance indicators. Vestnik IrGTU, 2014, no. 8(91), pp. 41–44 (in Russ.).

[13] Dudkin Yu.P., Gladkikh V.A., Fomin G.V. Sposob upravleniya gazoturbinnym dvigatelem [The method of controlling a gas turbine engine]. Patent no. 2436978 RF, 2011.

[14] Dudkin Yu.P., Gladkikh V.A., Fomin G.V. Ustroystvo dlya upravleniya gazoturbinnym dvigatelem [Device for controlling a gas turbine engine]. Patent no. 2425238 RF, 2011.

[15] Dobryanskiy G.V., Abramov V.A., Timoshin S.A., Guminskiy A.A., Minin O.P. Sistema avtomaticheskogo upravleniya gazoturbinnym dvigatelem [Gas turbine engine automatic control system]. Patent no. 2378521 RF, 2010.

[16] Dudkin Yu.P., Gladkikh V.A., Fomin G.V. Sposob upravleniya gazoturbinnym dvigatelem [The method of controlling a gas turbine engine]. Patent no. 2418182 RF, 2011. nomer byulletenya?

[17] Murav’yev I.K. Improving the control systems of gas turbine plants to ensure the efficiency of combined cycle power plants taking into account the changing regime and climatic factors. Matematicheskiye metody v tekhnike i tekhnologiyakh — MMTT, 2016, no. 5(87), pp. 99–100 (in Russ.).

[18] Gol’berg F.D., Gurevich O.S., Petukhov A.A. Using the “virtual engine” software in automatic control system of gas turbine engine. Vestnik Samarskogo universiteta. Aerokosmicheskaya tekhnika, tekhnologii i mashinostroyeniye, 2016, vol. 15, no. 4, pp. 47–56 (in Russ.), doi: 10.18287/2541-7533-2016-15-4-47-56