Numerical Simulations of Laminar Film Condensation of H₂O/Air or H₂O/CO₂ on a Vertical Plate

Abstract

The liquid film thickness seriously affects the distribution of temperature, velocity, and components near the interface for steam condensation in the presence of small concentration noncondensable gas. The liquid film thickness for H₂O/CO₂ forced convection condensation separation on vertical plate has not been studied numerically. Thus, volume of fluid model and a phase change model were used to study steam condensation in the presence of noncondensable gases. The calculations studied the effects of velocity, surface subcooling, and noncondensable gas mole fraction on the heat transfer for H₂O/air or H₂O/CO₂ mixtures. The results show that the predicted heat transfer coefficients agree well with previous experimental data. The gas and liquid film thicknesses controlling the condensation heat transfer in the presence of a noncondensable gas become thicker as the mixture flows along the cooled wall. The condensate mass flow rate and the heat transfer coefficient are both seriously reduced by the noncondensable gas. The condensate heat transfer in the presence of noncondensable gases is mainly determined by the diffusion coefficient and the thermal conductivities of the components in the gas film layer.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Key Research and Development Program of China (No. 2016YFB0600105), the Beijing Scholars Program (2015 No. 022), Beijing Postdoctoral Research Foundation (2021-ZZ-112), and the Fundamental Research Funds for Beijing University of Civil Engineering and Architecture(X21016).

Notes on contributors

Junhui Lu

Junhui Lu is a lecture in the School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture (BUCEA). He received his Ph.D. in 2020 from Department of Energy and Power Engineering, Tsinghua University. He has been working at BUCEA since 2020. He is currently working on heat and mass transfer of condensation and adsorption.

Kexin Ren

Kexin Ren is currently a master’s student at the School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, under the supervision of Professor Suilin Wang. She received B.E. degree in 2019 from Nanjing Tech University. She is currently working on heat and transfer of condensation and adsorption.

JinJing Tang

JinJing Tang is currently a master’s student at the School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture (BUCEA), under the supervision of Professor Suilin Wang. She received B.E. degree in 2019 from BUCEA. She is currently working on heat transfer of condensation and adsorption.

Suilin Wang

Suilin Wang is a professor in the School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture. She received her Ph.D. in 2006 from Beijing University of Science and Technology. She is currently working on energy-saving and energy-efficient use of building energy systems, and deep recovery and utilization of waste heat.