International Journal of Advanced Nuclear Reactor Design and Technology (Jan 2020)
Numerical investigation of the thermal-hydraulic characteristics of AP1000 steam generator U-tubes
Abstract
Steam generators (SGs) are vital heat exchangers that connect the primary and secondary sides in power plant systems. Based on the AP1000 SG, a numerical model of SG U-tubes is developed. The interior flow and heat transfer behaviors of the SG are simulated using CFX thermal phase change model. The numerical model reasonably predicts the distributions of the thermal-hydraulic behaviors, including the velocity, temperature, steam quality, void fraction and heat transfer coefficient. The slip-ratio of the secondary side increases and then decreases slowly along the axial direction. The simulated heat transfer coefficient agrees with the calculation of the Rohsenow formula. The most serious flow-induced vibration (FIV) damage is expected at the angles of θ = 60° in cold leg and θ = 110° in hot leg according to the fluid density and velocity of the secondary side in U-bend region, and the simulated results agree with the drift-flux model. The current simulation results may provide useful technical information for the optimal structural design of SGs.