Uncertainty Propagation in Integrated Airframe Propulsion System Analysis for Hypersonic Vehicles
Air{breathing hypersonic vehicles are based on airframe{integrated SCRAMjet engine. The elongated forebody which serves as the inlet of the engine is subject to harsh aerothermodynamic loading which causes it to deform. Unpredicted deformations may produce unstart, combustor chocking or structural failure due to increased loads. This study presents a framework allowing one to assess the impact of aerothermoelastic deformations on the engine performance prediction. Aerothermoelastic deformations are calculated for trajectories and angle of attack and transferred to a SCRAMjet engine analysis. Uncertainty associated with deformation prediction is propagated to the engine performance analysis. The importance of modeling the aerodynamic heating and aerothermoelastic deformations at the cowl of the inlet is noted. The cowl deformation is the main contributor to uncertainty and sensitivity of the propulsion system analysis.
Impact of Aeroelastic-P ropulsive Interactions on Flight Dynamics of a Hypersonic Vehicle
Many air-breathing hypersonic vehicle design concepts utilize the lower surface of an elongated fuselage forebody to provide aerodynamic compression for a supersonic combustion ramjet module, or a scramjet. This highly integrated design approach creates the potential for an unprecedented form of aeroelastic-p ropulsive interaction in which deflections of the vehicle fuselage give rise to propulsive force and moment variations that may impact the vehicle's flight dynamic characteristics. This investigation examines the potential for such interactions using a math model that describes the longitudinal flight dynamics, propulsion system, and first seven elastic modes of a hypersonic vehicle concept. Estimates of the propulsion system sensitivity to angle-ofattack variations and modal fuselage deflections are presented and compared with predictions based on an earlier reference. The combined aeroelastic-propulsive model is used to illustrate a variation in the vehicle's longitudinal flight dynamics with the propulsion system sensitivities. Numerical values for the completed model at flight conditions of Mach 6 and Mach 10 are presented.
Simulation and control of hybrid renewable energy system connected to the grid
This paper presents a control and simulation of hybrid renewable energy system connected to the grid. The studied system includes a photovoltaic panel, synchronous permanent magnet generator based wind turbine, and a battery for storage energy. The PV array and wind systems are connected to the common DC bus by a boost converter. The battery is connected by a bi-directional DC/DC converter, and then integrated into the AC utility grid via a common DC/AC inverter. In order to extract the maximum energy, a simulation study has been carried out according to the meteorological conditions (wind speed and variable solar irradiance) while maintaining power quality at a satisfactory level. In order to capture the maximum power, a MPPT algorithm is applied for both wind turbine and photovoltaic panel. The modeling and simulation of the whole system has been performed under Matlab/Simulink environment. The obtained results show that the current and the voltage of grid side are sinusoidal and alternative forms, and the power injected to the grid is around the power produced by the hybrid system.