Effect of the heat-transfer agent flow nonstationarity in the matrix channel of a rotating heat exchanger on its thermal parameters with the laminar flow

The paper studies influence of the non-stationarity process of the laminar gas flow in the band flat matrix channel of the rotating heat exchanger on its thermal characteristics. Conjugate heat transfer was mathematically simulated with the airflow along the steel walls forming the channel under study. In view of peculiarities of the rotating heat exchanger operation and to obtain parameters of the conjugate heat transfer in the nominal mode, mathematical simulation was performed many times using the results previously obtained as the initial conditions for the following calculations. It was established that gas flow in the investigated matrix channel of the heat exchanger became cyclically repetitive after the sixty cycles. Distribution curves of Nusselt criterion local values along the channel length at all time steps of the gas flow process, as well as the Nusselt criterion values averaged over the channel length were obtained. It was shown that the length-averaged Nusselt criterion value was smoothly increasing with time. The time-averaged Nusselt criterion value was determined, and it was somewhat exceeding the values obtained in the stationary setting.

References

[1] Grachev L.P., Bulat P.V., Esakov I.I. et al. Method for burning super-poor fuel mixtures in the combustion chamber of the energy microturbine by means of the streamer discharge. Problemy regionalnoy energetiki [Problems of the Regional Energetics], 2018, no. 2, doi: https://doi.org/10.5281/zenodo.1343414 (in Russ.).

[2] Kostyukov A.V., Kosach L.A., Gornovskiy A.S. et al. Multi-purpose highly efficient microturbines with a capacity of 50 kW. Naukograd, 2016, no. 2, pp. 23–26. (In Russ.).

[3] Shevelev D.V., Somkin S.A. Choosing optimal parameters of the thermodynamic cycle of gas microturbine with cogeneration. Inzhenernyy zhurnal: nauka i innovatsii [Engineering Journal: Science and Innovation], 2014, no. 9, doi: http://dx.doi.org/10.18698/2308-6033-2014-9-1277 (in Russ.).

[4] Shah R. Compact heat exchangers for microturbines. URL: https://www.sto.nato.int/publications/STO%20Educational%20Notes/RTO-EN-AVT-131/EN-AVT-131-02.pdf (accessed: 15.02.2022).

[5] Safonov E.V., Bromer K.A., Shults A.O. et al. Design features of effective recuperator of microturbine. Vestnik YuUrGU. Ser. Mashinostroenie [Bulletin of the South Ural State University. Ser. Mechanical Engineering Industry], 2013, no. 2, pp. 63–67. (In Russ.).

[6] Kostyukov A.V., Alekseev R.A. Increase of effectiveness of a rotary heat exchanger of a small-size gas turbine engine. Izvestiya MGTU MAMI, 2012, no. 1, pp. 52–58. (In Russ.).

[7] Kilkovský B., Jegla Z. Preliminary design and analysis of regenerative heat exchanger. Chem. Eng. Trans., 2016, vol. 52, pp. 655–660, doi: https://doi.org/10.3303/CET1652110

[8] Melian E., Klein H., Thißen N. Improvement of a nusselt-based simulation model for heat transfer in rotary heat exchangers. Energies, 2021, vol. 14, no. 1, art. 10, doi: https://dx.doi.org/10.3390/en14010010

[9] Kostukov A.V., Kosach L.A., Dementievet A.A. Experimental study of a rotary heat exchanger with a metal mesh matrix. J. Phys.: Conf. Ser., 2021, vol. 2096, art. 012205, doi: https://doi.org/10.1088/1742-6596/2096/1/012205

[10] Konecna E., Masa V. Review of gas microturbine application in industry. Chem. Eng. Trans., 2019, vol. 76, pp. 355–360, doi: http://dx.doi.org/10.3303/CET1976060

[11] Wołowicz M., Kolasi´nski P., Badyda K. Modern small and microcogeneration systems-a review. Energies, 2021, vol. 14, no. 3, art. 785, doi: https://doi.org/10.3390/en14030785

[12] Neale A., Derome D., Blocken B. et al Jan. Determination of surface convective heat transfer coefficients by CFD. Proc. 11th NBEC Canadian Building Sci. Technol. Conf., 2007. URL: https://www.researchgate.net/publication/267426300_Determination_of_Surface_Convective_Heat_Transfer_Coefficients_by_CFD (accessed: 15.02.2022).

[13] Reis M.C., Sphaier L.A. Analysis of angular heat conduction in rotary heat regenerators. In: 13th Brazilian Congress of Thermal Sciences and Engineering (ENCIT), 2010. URL: https://www.abcm.org.br/anais/encit/2010/PDF/ENC10-0178.pdf (accessed: 15.02.2022).

[14] Kulinchenko V.R. Spravochnik po teploobmennym raschetam [Handbook on heat transfer calculations]. Kiev, Tekhnika Publ., 1990. 163 p. (In Russ.).

[15] Matyushenko A.A., Stabnikov A.S., Garbaruk A.V. Criteria of computational grid generation for turbulence models taking into account laminar-turbulent transition. J. Phys.: Conf. Ser., 2019, vol. 1400, art. 077047, doi: https://doi.org/10.1088/1742-6596/1400/7/077047

[16] Efremov V.R., Kurulin V.V., Kozelkov A.S. The use of wall functions for simulating the turbulent thermal boundary layer. Zhurnal vychislitelnoy matematiki i matematicheskoy fiziki, 2019, vol. 59, no. 6, pp. 1037–1046, doi: https://doi.org/10.1134/S004446691906005X (in Russ.). (Eng. version: Comput. Math. and Math. Phys., 2019, vol. 59, no. 6, pp. 1006–1014 (2019). https://doi.org/10.1134/S0965542519060058)