| Autor: |
Minko, K. B., Yan'kov, G. G., Artemov, V. I., Krylov, V. S., Klementiev, A. A. |
| Zdroj: |
Thermal Engineering; Sep2021, Vol. 68 Issue 9, p705-716, 12p |
| Abstrakt: |
Based on an analysis of modern approaches to the calculation of heat-and-mass transfer processes in water-cooled condensers, an engineering model of steam condensation from a flowing steam-gas mixture (SGM) on a bundle made of smooth horizontal tubes is proposed. This model was verified against available experimental data and predictions by the detailed CFD-model described in our previous publications. The engineering model adequately describes the experimental data. Local characteristics of heat-and-mass transfer processes were studied in small-scale condenser tube bundles with a constant or variable cross-section fed with SGM having a volume fraction of air from 0 to 15%. For the case with an air volume fraction of 10% at the condenser inlet, the distributions of heat-transfer coefficient, heat flux, and total removed power removed along the SGM flow, as well as the distribution of heat flux density among the tubes of the first, fifth, and ninth rows are presented. A comparative analysis revealed that, despite almost the same average characteristics, the distribution of local heat-transfer coefficients is more uniform in a tube bundle with a decreasing cross-section along the SGM flow. The distributions of local heat-and-mass transfer characteristics calculated by the engineering model agree quite well with the predictions by the detailed CFD-model. Some qualitative disagreement can be explained by the fact that the engineering model uses characteristics averaged over the cross section of a row, and the detailed CFD model takes into account the nonuniformity in the velocity field and composition of the SGM flowing over the tube bundle. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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