Computer Modelling of Non-Stationary Flows with Phase Transitions in Countercurrent Heat Exchangers

The problems of mathematical and numerical modeling of non-stationary processes of heat and mass transfer in countercurrent heat exchangers with phase transitions in heat carriers are discussed. A one-dimensional problem statement with spatially distributed flow parameters (temperature, density, velocity, heat transfer coefficient) is considered. A method for determining the two-phase zone of the vapor-liquid state and a method for calculating its parameters is proposed. Examples of numerical simulation for a specific heat exchanger with heat carriers in the form of air and liquid oxygen, which boils during the flow are given. The influence of the heat transfer coefficient on the length of the boiling zone is shown, which in turn has a significant effect on the heat transfer process and, accordingly, on the temperature distribution in the coolant flows. In the end, this significantly affects the operation of the heat exchanger.

Keywords

mathematical modelling; numerical simulation; phase transition counterflow heat exchanger; heat transfer coefficient.

References

1. Minenko A.S., Radevich E.V. [Approximate Analysis of the Convective Stefan Problem]. Informatics and Cybernetics, 2017, no. 3 (9), pp. 100-105. (in Russian)
2. Kot V.A. [A New Approach to Approximate Solution of the Stefan Problem with a Convective Boundary Condition]. Doklady of the National Academy of Sciences of Belarus, 2020, vol. 64, no. 4, pp. 495-505. (in Russian)
3. Tolstykh V.K., Pshenychnyi K.A. [Mathematical Modelling of Unsteady Heat Processes in Countercurrent Heat Exchangers]. Vestnik Tomskogo Gosudarstvennogo Universiteta. Upravlenie, Vychislitel'naya Tekhnika i Informatika. [Tomsk State University Jounal of Control and Computer Science], 2020, no. 1, pp. 55-62. (in Russian)
4. Butterwoth D., Hewitt G.F. Two-phase and Heat Transfer. Oxford, New York, Oxford University Press, 1977.
5. Kutateladze S.S. Teploperedacha pri kondensatsii i kipenii [Heat Transfer During Condensation and Boiling]. Moscow, Meshgiz, 1952.
6. Grigir'ev V.A., Krokhin Yu.I. Teplo- i massoobmennye apparaty kriogennoy tekhniki [Heat and Mass Transfer Devices of Cryogenic Equipment]. Moscow, 1982.
7. Alekseev V.P. Raschet i modelirovanie apparatov kriogennykh ustanovok [Calculation and Modeling of Cryogenic Plant Apparatuses]. Leningrad, Energoatomizdat, Leningradskoe otdelenie, 1987.
8. Kreith F., Black W.Z. Basic Heat Transfer. New York; Cambridge; Hagerstown; Philadelphia; San Francisco; London; Mexico; Sao Paulo; Sydney, Harper and Row, 1983.
9. Baskakov A.P., Berg B.V., Vitt O.K. Teplotekhnika [Heat Engineering]. Moscow, Energoatomizdat, 1991.
10. Volkov M.G. [Oil-Water-Gas Flow Calculations in Vertical Wells]. Problemy sbora, podgotovki i transporta nefti i nefteproduktov [Problems of Collecting, Preparing and Transporting Oil and Petroleum Products], 2017, no. 3, pp. 9-42. (in Russian)
11. Ivashnev O.E. About the Features of Modeling the Flows of a Boiling Liquid. Fluid Dynamics, 2008, vol. 43, no. 3, pp. 64-76. DOI: 10.1134/S0015462808030071
12. Samarskii A.A. Teoriya raznostnykh skhem [Theory of Difference Schemes]. Moscow, Nauka, 1977.
13. Bakhvalov N.S., Zhidkov N.P., Kobel'kov G.M. Chislennye metody [Numerical Methods]. Moscow, Fizmatlit, Laboratoriya bazovykh znaniy, 2002.
14. Sychev V.V., Vasserman A.A., Kozlov A.D., Spiridonov G.A., Tsymarnyi V.A. Termodinamicheskie svoistva kisloroda [Oxygen Thermodynamic Properties]. Moscow, Izdatel'stvo standartov, 1981.
15. Vargaftik N.B. Spravochnik po teplofizicheskim svoistvam gazov i zhidkostei [Handbook on Thermophysical Properties of Gases And Liquids]. Moscow, Nauka, 1972.