Design of Rotor Blades for Vertical Axis Wind Turbine with Wind Flow Modifier for Low Wind Profile Areas

This work focuses on the design and analysis of wind flow modifier (WFM) modeling of a vertical axis wind turbine (VAWT) for low wind profile urban areas. A simulation is carried out to examine the performance of an efficient low aspect ratio C-shaped rotor and a proposed involute-type rotor. Further, the WFM model is adapted with a stack of decreased diameter tubes from wind inlet to outlet. It accelerates the wind velocity, and its effectiveness is examined on the involute turbine. Numerical analysis is performed with a realizable K-ε model to monitor the rotor blade performance in the computational fluid dynamics (CFD) ANSYS Fluent software tool. This viscous model with an optimal three-blade rotor with 0.96 m2 rotor swept area is simulated between the turbine rotational speeds ranging from 50 to 250 rpm. The parameters, such as lift–drag coefficient, lift–drag forces, torque, power coefficient, and power at various turbine speeds, are observed. It results in a maximum power coefficient of 0.071 for the drag force rotor and 0.22 for the lift force involute rotor. Moreover, the proposed WFM with an involute rotor extensively improves the maximum power coefficient to an appreciable value of 0.397 at 5 m/s wind speed, and this facilitates efficient design in the low wind profile area.

Flow modification enhancing the growth rate in top seeded solution growth of SiC crystals

Based on the verified multiphysics simulation, a model describing C transport contributing to crystal growth was suggested. Based on the further understanding of C transport, the growth rate was enhanced by adopting a flow modifier in the melt.

Tensile Properties and Degradability of Polyvinyl Alcohol and Starch Succinate Blend

The purpose of this study was to determine the tensile properties of biodegradable Polyvinyl Alcohol (PVA) impregnated with commercial grade starch succinate (SS). PVA is a hydrophilic and hygroscopic polymer, and inclusion of SS reduces PVA's hygroscopicity and hydrophilicity. The compounding of PVA with SS was prepared by using a twin screw extruder with fixed flow modifier. The ratios of SS were varied between 5% to 20%. Melt flow index, tensile properties, soil burial and sun exposure degradability were investigated in this study. Tensile strength was observed to increase proportionate to the amount of SS incorporated while the blends were found to have greater flexibility as their elongation increases as their modulus dropped. SS was found to have greater flexibility chain which imparted greater elongation during stretching test. Higher content of SS was found to impart better degradation rate as derived from visual observation of the samples exposed to sunlight and soil burial.