A thermo-hydraulic model for calculating capacity, heat transfer coefficient and void fraction of an inclined aircooled steam condenser is presented. The condenser tube has an elongated-slot cross-section, with inner dimensions of 214 × 16 mm. The tube is 10.7 m long. The model is for downward inclination angles from 0-90°, with co-current vapor and condensate flow. The cooling air is in cross flow. This model is developed based on existing models for inclined, stratified-flow condensation. These have been adapted to the flattened-tube air-cooled condenser geometry and conditions. The model couples both air- and steamside behavior in order to accurately resolve the variation in heat transfer coefficients, temperature difference, and heat flux. On the steam side, the model is for stratified flow, and separates the flow into two sections: a falling film along the wall, and an axially-flowing condensate river along the tube bottom. The axially-flowing condensate river is modeled using open-channel-flow theory. On the air side, heat transfer coefficient is determined from a combination of empirical correlation and CFD. The model and experimental results show agreement within 5% in capacity and overall heat transfer coefficient for all tube inclinations.
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