Investigation of the process of cooling cryogenic pipelines with liquid hydrogen to optimize firing tests of rocket engines

Purpose. Development of a mathematical model that adequately describes the non-stationary process of cooling long cryogenic pipelines with liquid hydrogen and makes it possible to determine optimal operating parameters that ensure minimal refrigerant consumption in preparation for firing tests of liquid rocket engines.
Methods. A vacuum-insulated pipe made of cryogenic steel with a total length of 272.5 m, with a bore diameter of 96 mm and a wall thickness of 2 mm was used as the modeling object. The total weight of the shut-off equipment located on the main line is 246 kg. Liquid supercooled hydrogen with an inlet temperature of 19 K is supplied to the pipeline under an excess pressure of 0.2 MPa. The ambient temperature is 293 K.
Results. In this paper, we propose a model for cooling long insulated pipelines when liquid water flows through them, which makes it possible to determine the flow parameters at various points in time and estimate the time when the main line enters operating mode. Based on the proposed model, an automated algorithm was developed for calculating the cooling process of a long pipeline with cryogenic components, which makes it possible to obtain data for constructing the temperature fields of the pipeline walls and the flow of transported cryoproducts at various time points, as well as to determine the time when the main line enters operation and the moment of the onset of a stationary single-phase flow. The results of the calculation are in good agreement with the experimental data.
Conclusion. Using this model under various initial and boundary conditions, it is possible to work out the optimal mode of real physical processes and achieve minimal losses of cryogenic components with minimal time spent in preparing bench systems for fire tests, as one of the stages of the production cycle of liquid propellants in mechanical engineering. 

1. Arkharov A.M., Kunis I.D. Cryogenic refueling systems of launch rocket and space complexes. Moscow: MGTU im. H.E. Bauman; 2006. 251 p. (In Russ.)

2. Darr S.R., Hartwig J.W. Development of universal two-phase heat transfer correlations for cryogenic transfer line chilldown. Proceedings of the 2018 AIAA Aerospace Sciences Meeting. Kissimmee: AIAA; 2017. https://doi.org/10.2514/6/2017-0904.

3. Hartwig J.W., Hu H., Styborski J., Chung J.N. Comparison of cryogenic flow boiling in liquid nitrogen and liquid hydrogen chilldown experiments. International Journal of Heat and Mass Transfer. 2015;88;662-673.

4. Yuranev O.A. Research of various methods of cooling cryogenic fuel tanks of rocket and space technology products. Vestnik Moskovskogo gosudarstvennogo tekhnicheskogo universiteta im. N.E. Baumana. Seriya: Mashinostroenie = Bulletin of the Bauman Moscow State Technical University. Series: Mechanical Engineering. 2018;(3):50-57. (In Russ.)

5. Fedyushin V.A. Development of a system for minimizing operational losses of argon in an oxygen shop. In: Energetika. Problemy i perspektivy razvitiya: tezisy dokladov 3-i Vserossiiskoi studencheskoi nauchnoi konferentsii = Energy. Problems and development prospects: abstracts of the 3rd All-Russian Student Scientific Conference. Tambov: TGTU; 2017. P. 137-138. (In Russ.)

6. Kutateladze S.S., Styrikovich M.A. Hydrodynamics of gas-liquid systems. 2nd ed., revised and supplemented. Moscow: Energiya; 1976. 296 p. (In Russ.)

7. Ginzburg I.P. Applied hydro-gas dynamics. Leningrad: Izd-vo LGU; 1958. 338 p. (In Russ.)

8. Antyukhov I.V. Investigation of heat exchange processes in cryogenic mains of rocket engines. In: Materialy XIII Mezhdunarodnoi konferentsii po prikladnoi matematike i mekhanike v aerokosmicheskoi otrasli (AMMAI'2020) = Proceedings of the XIII International Conference on Applied Mathematics and Mechanics in the Aerospace Industry (AMMAI'2020). Moscow: MAI; 2020. P. 118-121. (In Russ.)

9. Koshkin V.K., Kalinin E.K., Dreitser G.A., Yarkho S.A. Unsteady heat transfer. Moscow: Mashinostroenie; 1973. 327 p. (In Russ.)

10. Hartwig J., Vera J. Numerical modeling of the transient chilldown process of a cryogenic propellant transfer line. Journal of Thermophysics and Heat Transfer. 2016;30(2):1-7.

11. Filin N.V., Bulanov A.B. Liquid cryogenic systems. Leningrad: Mashinostroenie, Leningr. otd-nie; 1985. 246 p. (In Russ.)

12. Belyakov V.P. Cryogenic equipment and technology. Moscow: Energoizdat; 1982. 272 р. (In Russ.)

13. Val'tsiferov Yu.V., Polezhaev V.I. Convective heat transfer in a closed axisymmetric vessel with a curved generatrix in the presence of a phase interface and phase transitions. Izvestiya Akademii nauk SSSR. Mekhanika zhidkosti i gaza = Proceedings of the USSR Academy of Sciences. Fluid and Gas Mechanics. 1975;(6):126-134. (In Russ.)

14. Kalyadin O.V., Sergeev A.V. Development of a mathematical model of the process of cooling long pipelines for transportation of liquid hydrogen. In: Al'ternativnaya i intellektual'naya energetika: materialy II Mezhdunarodnoi nauchno-prakticheskoi konferentsii = AIE: materials of the 2nd International scientific and practical conference. Voronezh: Voronezh. gos. tekhn. un-t; 2020. P. 208-209. (In Russ.)

15. Grebennikov A.A., Kalyadin O.V., Sergeev A.V., Sviridov O.P., Golev I.M., Kuryanov S.A. Modeling of technological processes of supercooling of cryogenic liquids. Vestnik Voronezhskogo gosudarstvennogo tekhnicheskogo universiteta = Bulletin of the Voronezh State Technical University. 2016;12(4):85-91. (In Russ.)