Abstract
Gradient heat flux measurement (gradient heatmetry) is a modern technology for measuring heat flux per unit area using gradient-type sensors. Since 2015, gradient heatmetry has been used to study heat transfer in film condensation of saturated steam on the inner and outer surface of tubes. This measurement method offers greater information capabilities than the more widely used thermometry when the heat flux is calculated from the temperature measured with thermocouples. The advantage of gradient heatmetry results from abnormally fast response time of sensors which is about 10–8–10–9 s. Therefore, they may be considered almost inertia-less measuring devices. Direct measurement of heat flux per unit area reduces the total uncertainty in calculating local and average heat-transfer coefficients. Heat transfer in film condensation of saturated steam on the outer and inner surfaces of tubes was studied using gradient heatmetry. Gradient heat flux sensors (GHFS) made of single-crystal bismuth were used on the outer surface, while heterogeneous GHFSs made of Grade 12Kh18N9T steel + Ni composition were installed on the inner surface. In both cases, reference tests were performed on vertical tubes. Their results confirmed the excellent information capability of this approach and its applicability for estimating heat flux. A series of experiments was carried out to study heat transfer during film condensation of saturated steam on the outer and inner surfaces of inclined pipes. The highest heat-transfer coefficient of 6.94 kW/(m2 K) in condensation of saturated steam on the outer surface of a tube is observed for the tube inclined at an angle of 20° to the vertical. This value exceeds the heat-transfer coefficient on a vertical tube by 14.9%. The highest heat-transfer rate in condensation on the inner surface was observed for the tube inclined at 60° to the vertical.
Similar content being viewed by others
REFERENCES
G. Fan, P. Tong, Z. Sun, and Y. Chen, “Development of a new empirical correlation for steam condensation rates in the presence of air outside vertical smooth tube,” Ann. Nucl. Energy 113, 139–146 (2018). https://doi.org/10.1016/j.anucene.2017.11.021
Y. G. Lee, Y. J. Jang, and D. J. Choi, “An experimental study of air–steam condensation on the exterior surface of a vertical tube under natural convection conditions,” Int. J. Heat Mass Transfer 104, 1034–1047 (2017). https://doi.org/10.1016/j.ijheatmasstransfer.2016.09.016
J. X. Zhang and L. Wangb, “Experimental study of air accumulation in vapor condensation across horizontal tube,” Int. J. Heat Mass Transfer 111, 860–870 (2017). https://doi.org/10.1016/j.ijheatmasstransfer.2017.04.010
K.-W. Lee, H. C. No, I.-C. Chu, Y. M. Moon, and M. H. Chun, “Local heat transfer during reflux condensation mode in a U-tube with and without noncondensible gases,” Int. J. Heat Massc Transfer 49, 1813–1819 (2006). https://doi.org/10.1016/j.ijheatmasstransfer.2005.11.011
S. A. Nada and M. S. Hussein, “General semi-empirical correlation for condensation of vapor on tubes at different orientations,” Int. J. Therm. Sci. 100, 391–400 (2016). https://doi.org/10.1016/j.ijthermalsci.2015.10.023
J. Havlík and T. Dlouhý, “Condensation of the air–steam mixture in a vertical tube condenser,” EPJ Web Conf. 114, 02037 (2016). https://doi.org/10.1051/epjconf/201611402037
M. Kubín, J. Hirš, and J. Plášek, “Experimental analysis of steam condensation in vertical tube with small diameter,” Int. J. Heat Mass Transfer 94, 403–410 (2016). https://doi.org/10.1016/j.ijheatmasstransfer.2015.11.022
V. V. Lel, F. Al-Sibai, and U. Renz, “Local thickness and wave velocity measurement of wavy films with a chromatic confocal imaging method and a fluorescence intensity technique,” Exp. Fluids 39, 856–864 (2005). https://doi.org/10.1007/s00348-005-0020-x
S. Sapozhnikov, V. Mityakov, and A. Mityakov, Heatmetry: The Science and Practice of Heat Flux Measurement (Springer-Verlag, Cham, 2020). https://doi.org/10.1007/978-3-030-40854-1
V. Mityakov, A. Gusakov, V. Seroshtanov, and M. Grekov, “Investigation of flow and heat transfer at the circular fins,” MATEC Web Conf. 245, 06001 (2018). https://doi.org/10.1051/matecconf/201824506001
S. Z. Sapozhnikov, V. Y. Mityakov, A. V. Mityakov, A. Y. Babich, and E. R. Zainullina, “The study of heat flux measurement for heat transfer during condensation at pipe surfaces,” Tech. Phys. Lett. 45, 321–323 (2019). https://doi.org/10.1134/S1063785019040163
A. Yu. Babich, E. R. Zainullina, V. V. Subbotina, V. Yu. Mityakov, and S. Z. Sapozhnikov, “Investigation of saturated vapor condensation by the gradient heat metering method,” Vestn. Rybinsk. Gos. Aviats. Tekhnol. Akad. im. P. A. Solov’eva, No. 1 (44), 44–49 (2018).
J. Y. Tinevez, N. Perry, and J. Schindelin, “TrackMate: An open and extensible platform for single-particle tracking,” Methods 115, 80–90 (2019). https://doi.org/10.1016/j.ymeth.2016.09.016
M. Jakob, S. Erk, and H. Eck, “Improved measurements and calculations of the heat transfer for flowing steam condensing in a vertical tube,” Phys. Z. 36, 73 (1935).
P. V. Muratov and R. I. Pashkevich, “Reflux condensation of steam inside a short vertical large diameter tube,” Int. J. Heat Mass Transfer 91, 494–501 (2015). https://doi.org/10.1016/j.ijheatmasstransfer.2015.07.075
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated by T. Krasnoshchekova
Rights and permissions
About this article
Cite this article
Sapozhnikov, S.Z., Mityakov, V.Y., Mityakov, A.V. et al. An Investigation into Film Condensation of Saturated Steam on Tube Surfaces by a Gradient Heatmetry. Therm. Eng. 68, 794–801 (2021). https://doi.org/10.1134/S004060152109007X
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S004060152109007X