Influence of wall temperature on condensation rate in duct flow of humid air : a comprehensive computational study
DOI:
https://doi.org/10.24425/ather.2024.151229Abstract
In engineering phase-change phenomena are found in a multitude of applications, ranging from refrigeration and air conditioning to steam turbines and petroleum refining. This study investigates the flow of moist air in a circular duct where water vapour condenses in contact with the cold wall of the duct. The investigation delves into the relationship between the condensation mass transfer rate, the heat transfer between the bulk flow and the wall, and the temperature of the wall. The volume of fluid model coupled with the Lee evaporation-condensation model was employed. Five simulations were carried out, involving different wall temperatures while maintaining the same inlet conditions. Condensation was more pronounced at lower wall temperatures, which aligns with the expectations. The heat transfer between the bulk flow and the wall decreased with the decreasing temperature difference. Interestingly, the findings revealed that the surface heat transfer coefficient increased as the wall temperature approached the temperature of the bulk flow. The success of the study suggests potential applications in optimising thermal management systems, with implications for industries where accurate predictions of moisture behaviour and heat transfer are crucial.References
[1] Cengel, Y.A. (2002). Heat Transfer: A practical approach. McGraw-Hill.
[2] Cengel, Y.A., Boles, M A., & Kanoğlu, M. (2011). Thermodynamics: An engineering approach. McGraw-Hill.
[3] Ganapathy, H., Shooshtari, A., Choo, K., Dessiatoun, S., Alshehhi, M.M.M.O., & Ohadi, M. (2013). Volume of fluidbased numerical modeling of condensation heat transfer and fluid flow characteristics in microchannels. International Journal of Heat and Mass Transfer, 65, 62‒72. doi: 10.1016/j.ijheatmasstransfer.2013.05.044
[4] Phan, T.H., Won, S.S., & Park, W.G. (2018). Numerical simulation of air-steam mixture condensation flows in a vertical tube. International Journal of Heat and Mass Transfer, 127,568‒578. doi: 10.1016/j.ijheatmasstransfer.2018.08.043
[5] El Baamrani, H., Bammou, L., Aharoune, A., & Boukhris, A. (2021). Volume of fluid (VOF) modeling of liquid film evaporation in mixed convection flow through a vertical channel. Mathematical Problems in Engineering, 2021, 9934593.doi:10.1155/2021/9934593
[6] Kumar, G.V., Cammiade, L.M., Kelm, S., Prakash, K.A., Groß, E.M., Allelein, H.J., & Rohlfs, W. (2021). Implementation of a CFD model for wall condensation in the presence of non-condensable gas mixtures. Applied Thermal Engineering, 187,116546. doi: 10.1016/j.applthermaleng.2021.116546
[7] Pele, C., Baudoin, B., & Barrand, J.P. (1994). Effect of humid air flow rate on the filmwise condensation inside a vertical cooled pipe: numerical and experimental study. International Journal of Heat and Mass Transfer, 37(13), 1829‒1837. doi:10.1016/0017-9310(94)90323-9
[8] Szijártó, R., Badillo, A., Ničeno, B., & Prasser, H.M. (2017). Condensation models for the water–steam interface and the volume of fluid method. International Journal of Multiphase Flow, 93, 63‒70. doi: 10.1016/j.ijmultiphaseflow.2017.04.002
[9] Ansys Inc. (2022). Ansys Fluent theory guide.
[10] https://www.engineersedge.com/physics/viscosity_of_air_dynamic_and_kinematic_14483.htm [accessed 25 Dec. 2023].
[11] https://www.engineeringtoolbox.com/air-diffusion-coefficient-gas-mixture-temperature-d_2010.html [accessed 25 Dec.2023].
[12] https://www.engineeringtoolbox.com/water-properties-d_1573.html [accessed 20 Nov. 2023].
[13] https://www.engineersedge.com/physics/water__density_viscosity_specific_weight_13146.htm [accessed 25 Dec. 2023].
[14] https://wiki.anton-paar.com/en/water/ [accessed 25 Dec. 2023].
[15] Widiawaty, C.D., Siswantara, A.I., Gunadi, G.G.R., Pujowidodo, H., & Syafei, M.H G. (2020). A CFD simulation and experimental study: predicting heat transfer performance using SST k-ω turbulence model. IOP Conference Series: Materials Science and Engineering, 909(1), 012004. IOP Publishing.
[16] Močnik, U., Blagojevič, B., & Muhič, S. (2020). Numerical analysis with experimental validation of single-phase fluid flow in a dimple pattern heat exchanger channel. Journal of Mechanical Engineering/Strojniški Vestnik, 66(9), 544‒553. doi:10.5545/sv-jme.2020.6776
[17] Pawłucki, M., & Kryś, M. (2020). CFD for engineers, Gliwice: Helion (in Polish).
[18] Ansys Inc. (2015). Multiphase modeling using ANSYS Fluent.
[19] Ansys Inc. (2022). Ansys Fluent user's guide.
[20] https://www.nuclear-power.com/nuclear-engineering/fluid-dynamics/turbulent-flow/power-law-velocity-profile-turbulentflow/ [accessed 21 Nov. 2023].
[21] https://www.cfd-online.com/Wiki/Turbulence_intensity [accessed 21 Nov. 2023].
[22] Lee, W.H. (1980). A pressure iteration scheme for two-phase flow modeling. In Multiphase Transport Fundamentals, Reactor Safety, Applications (T.N. Veziroglu, ed.), (pp. 407‒431). Hemisphere.
[23] Antoine, M.C. (1888). Nouvelle relation entre les tensions et les temperatures. C. r. held Seanc. Acad. Sci. Paris, 107, 681‒684.
[24] Poling, B.E., Prausnitz, J.M., & O'connell, J.P. (2001). The properties of gases and liquids: Vol. 5. Mcgraw-Hill.
[25] Welty, J., Rorrer, G.L., & Foster, D.G. (2020). Fundamentals of momentum, heat, and mass transfer. John Wiley & Sons.
