Combined Heat Transfer Models and Dynamic Optimization Method for High-Pressure Feedwater Heat Exchanger in Nuclear Power Plant

In order to establish numerical heat transfer models suitable for high-pressure heaters in nuclear power units and improve calculation accuracy, four heat transfer calculation theories were introduced: the Dittus-Boelter model, Gnielinski model, Shell-side single phase model, and Shell-side horizontal tube condensation model. Four combined models based on different theories were applied to verify the design parameters of a high-pressure feedwater heater under various load conditions. The results indicated that the differences in heat transfer calculations among these model combinations were relatively minor, with a maximum deviation of 3.8% being observed compared to the designed heat transfer capacity of the heater. Through optimization of the established model combinations by the introduction of a dynamic correction coefficient, the maximum deviation of calculated heat transfer was reduced to 0.55%, demonstrating significant improvement in accuracy.