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Nuclear steam generator is a critical component of the pressurized-water nuclear power plant that plays an important role in security and efficiency of the nuclear power plant. Therefore, using assured thermo-hydraulic model to simulate the nuclear steam generator has particular importance. In this paper, the numerical solution of void fraction in horizontal nuclear steam generator in the steady state analysis is presented using Drift-Flux Model. For a two phase mixture of a gas or vapor and liquid flowing together in a channel, different internal flow geometries or structure can occur depending on the size or orientation of the flow channel, the magnitudes of the gas and liquid flow parameters, the relative magnitudes of this flow parameter, and on the fluid properties of the two phases. The Drift-Flux Model (DFM) is able to predict the void fraction in different geometries. The drift velocity in various two phase flow regimes for small and big diameter pipes is explained. VVER-1000 nuclear steam generator is simulated by DFM using the FLUENT 6.3.26 code. It is explained that void fraction in horizontal steam generator is strongly affected by using a perforated sheet in the top of the horizontal hot tubes. Validity and superiority of the DFM compared to the other two-phase models is proved. Simulation results are compared with RELAP5 and BAGIRA codes results. The calculated void fraction is in good agreement with measured data. The accuracy of the prediction shows that it is possible to use the DFM for thermal-hydraulic analysis in advanced models in nuclear power plant and other industries. This model can be used for assessment of experimental data and licensing processes. [ABSTRACT FROM AUTHOR]

Design and synthesis of a nonlinear generic supersonic flight vehicle longitudinal dynamics control for angle-of-attack, AOA, output tracking in the atmospheric flight is presented based on sliding mode control. A sliding mode observer is invoked to estimate AOA which is difficult to measure in practice. Large parameter uncertainties accommodation envisaged by designing adaptive mechanisms for both the control and observer and high chattering authority due to large deviations of aerodynamic coefficients arising from wind-tunnel measurements are inhibited. The employed method enables the sliding mode control design to exhibit the desired dynamic properties during the entire output-tracking process. Simulations results are presented to demonstrate the performance, robustness, and stability. [ABSTRACT FROM AUTHOR]