Sharif Digital Repository

The performance of an MHD generator utilizing plasma as working fluid has been assessed from the viewpoint of the second law of thermodynamics. The plasma flow in the generator linear duct has been solved by dividing the channel cross-section to an inviscid core region and the viscous boundary layers in the vicinity of the walls. The Hall effect has been taken into account and equilibrium ionization has been assumed. The dependence of the plasma properties such as Hall parameter, the coefficients of thermal and electrical conductivity, and viscosity on the plasma state has also been considered. Using the information obtained on the plasma behaviour in the generator, the entropy generation... 

Three-dimensional, transient turbulent particulate flow in an FCC riser is modeled using an Eulerian/Granular approach. The turbulence in the gas phase is described by a modified realizable (kg-g) closure model and the kinetic theory of granular flow (KTGF) is employed for the particulate phase. Separate simulations are conducted for a rectangular and a cylindrical riser with similar dimensions. The model predictions are validated against experimental data of Sommerfeld et al (2002) and also compared with the previously reported LES-KTGF simulations of Hansen et al (2003) for the rectangular riser. The (kg-g)-KTGF model does not perform as well as the LES-KTGF model for the riser with a... 

An improved phenomenological model is presented for numerical simulation of a Dielectric Barrier Discharge (DBD) plasma actuator for separation control of high angle of attack flow over a wind turbine airfoil. Based on existing numerical models and experimental measurements, a new model is proposed for prediction of the length of a plasma extent which is more consistent with previous observations. The electrical and hydrodynamic solvers used in the present study are validated against published experimental data. Then the applicability of a DBD actuator, mounted on a DU 91-W2-250 airfoil is extensively analyzed for a wide range of operating voltages and frequencies. The analysis is completely...