Development of a qualified nodalization for small-break LOCA transient analysis in PSB-VVER integral test facility by RELAP5 system code

This paper deals with development and qualification of a nodalization for modeling of the PSB-VVER integral test facility (ITF) by RELAP5/MOD3.2 code and prediction of its primary and secondary systems behaviors at steady state and transient conditions. The PSB-VVER is a full-height, 1/300 volume and power scale representation of a VVER-1000 NPP. A RELAP5 nodalization has been developed for PSBVVER modeling and a nodalization qualification process has been applied for the developed nodalization at steady state and transient levels and a qualified nodalization has been proposed for modeling of the PSB ITF. The 11% small-break loss-of-coolant-accident (SBLOCA), i.e. rupture of one of the hydroaccumulators (HA) injection lines in the upper plenum (UP) region of reactor pressure vessel (RPV) below the hot legs (HL), inlets has been considered for nodalization qualification process. The influence of the different steam generator (SG) nodalizations on the RELAP5 results and on the nodalization qualification process has been examined. The “steady state” qualification level includes checking the correctness of the initial and boundary conditions and geometrical fidelity. In the “transient” qualification level, the time dependent results of the code calculation are compared with the experimental time trends from both the qualitative and quantitative point of view. For quantitative assessment of the results, a Fast Fourier Transform Based Method (FFTBM) has been used. The FFTBM was used to establish a range in which the steam generators nodalizations can vary

Aerodynamic Analysis of Backward Swept in HAWT Rotor Blades Using CFD

The aerodynamical design of backward swept for a horizontal axis wind turbine blade has been carried out to produce more power at higher wind velocities. The backward sweep is added by tilting the blade toward the air flow direction. Computational Fluid Dynamics (CFD) calculations were used for solving the conservation equations in one outer stationary reference frame and one inner rotating reference frame, where the blades and grids were fixed in reference to the rotating frame. The blade structure was validated using Reynolds Averaged Navier-Stokes (RANS) solver in a test case by the National Renewable Energy Laboratory (NREL) VI blades results. Simulation results show considerable agreement with the NREL measurements. Standard K-ε turbulence model was chosen for simulations and for the backward swept design process. A sample backward sweep design was applied to the blades of a Horizontal Axis Wind Turbine (HAWT) rotor, and it is obtained that although at the lower wind velocities the output power and the axial thrust of the rotor decrease, at the higher wind velocities the output power increases while the axial thrust decreases. The swept blades have shown about 30 percent increase in output power and about 12 percent decrease in thrust at the wind speed of 14 m/s

Gis Based Multi-criteria Decision Analysis for the Streamlining of the Italian Network of Minor Airports

Alongside the general growth of air traffic in Primary-level airports of each country, since the 1990s the popularity of “individual” (private), General Aviation, non-scheduled “point to point” flights all over the world and in Italy increased. They have proved to be a valid alternative to rail and road transport for short-medium-distance journeys (for different classes of business and tourist passengers). Taking into consideration the national and international airport system development scenarios, the paper illustrates the results of in- depth analyses carried out aiming to build up a full integrated GIS-based Multi-criteria Decision Analysis evaluation methodology. This is geared towards formulating strategies for the development and streamlining of the 51 existing Italian minor airport network and for the identification of the right locations for new hubs that could be required for the construction of an efficient second-level air transport network (the “Highway in the Sky”). The methodology is implemented according to different evaluation levels that verify: the suitability of air- port services and infrastructure (status quo) and the attractiveness of airport hubs given the territorial facilities found in their catchment areas