## 1 Introduction  
The carbon dioxide emission from the industrial sector and power plants has contributed significantly to global climate change for several decades [1]. The rise in the average global temperature is one of the known impacts of emissions of greenhouse gases (mainly CO\({}_{2}\)) [2]. In 2021, the Intergovernmental Panel on Climate Change (IPCC) alleged that existing technologies, including Carbon Capture and Storage (CCS), are essential to achieve CO\({}_{2}\) reduction and climate change mitigation [3]. Climate change mitigation and adaptation measures likely need to include technologies that can reduce carbon emissions at fossil fuel production sites, capturing the carbon before it is released into the air. Water vapor and CO\({}_{2}\) are the main components of combustion products (flue gas). [PERSON] et al. [4] proposed a liquefied natural gas (LNG) and O\({}_{2}\) combustion gas-steam mixed cycle (GSMC) power generation scheme in which peak shaving, cold energy storage, and full CO\({}_{2}\) capture are all integrated. In GSMC, steam and CO\({}_{2}\) mixtures are condensed and separated in condensers and low/high-pressure heaters, with the condensation pressure exceeding 10 MPa in vacuum conditions. For the transformation of CO\({}_{2}\) capture in existing coal-fried power plants, [PERSON] et al. [5] studied the efficient power generation model with a high CO\({}_{2}\) capture rate, and the range of its steam-CO\({}_{2}\) mixture condensation and separation pressure also ranges from around 30 kPa to 10 Mpa. In a classical chemical cycle combustion process, fuel is oxidized by metal oxides in a fuel reactor. The exhaust stream, primarily comprising CO2 and H2O, can also be purified to mainly CO2 by condensing the H2O [6]. Thus, steam-CO2 mixture condensation may appear in wide areas and state ranges for component separation and CO2 capture [4; 5; 6]. The condensation of water vapor with air, N2, O2, CH4, H2, He, NH3, or other gases has been widely studied and summarized by scholars. [PERSON] et al. [7] experimentally studied the effect of non-condensable gas (NCG) on the condensation heat transfer of water vapor with a 0.05-0.5 air mass fraction on the isothermal vertical aluminum plate. They also discussed changes in the condensation mode with surface subcooling and air concentration. [PERSON] et al. [8] obtained an extensive database of steam-air mixtures and steam-helium mixtures and investigated the local heat transfer of steam in the presence of NCGs in vertical tubes. [PERSON] [9] measured the heat transfer of film condensation on vertical plate surfaces, and the approximate theoretically based equations were obtained in relation to the mass flux of vapor to the condensing surface (condensation rate) to the free-stream and condensate surface conditions. [PERSON] et al. [10] conducted condensation air and water vapor experiments on vertical and horizontal plates. [PERSON] et al. [11] conducted a vapor condensation experiment with air as an NCG on a horizontal plate. The above experimental results all show that the existence of a small amount of NCG can greatly affect the condensation heat transfer process. In the laminar flow regime, [PERSON] et al. [12] found that a 1.5% volume fraction of air will bring about a 50% decrease in the condensation heat transfer coefficient of steam. The condensation features of a non-azeotropic mixture are different from those of steam-NCG mixtures. [PERSON] et al. [13] analyzed the condensation heat transfer characteristics of a steam/NH3 mixture and considered the effect of gas concentration on condensation. [PERSON] et al. [14; 15] and [PERSON] et al. [16] developed a boundary layer theory for the condensation of a steam-air mixture on horizontal and vertical plate surfaces, which is a predictive model that is easy to both build and compute. The boundary layer theory can reveal the condensation mechanism of a steam-NCG mixture with relative clarity, and several studies based on this theory have been carried out [17; 18].