Constant speed horizontal axis wind turbines operate at power coefficients different than its maximum due to operation at different tip speed ratios (TSRs). Whereas rotational speed and the site wind speed distribution determine the TSR range of the operation, the pitch angle is significant for the aerodynamic performance of the wind turbine. In this paper, a blade element momentum approach is used to study the power production effects of pitch angle and rotational speed of NREL Phase VI wind turbine at different site wind distributions (characterized by Weibull distributions). It is shown that the best combination of rotational speed and pitch angle always occurs at the same pitch angle, but for different rotational speeds (other than the best one) the best pitch angle may vary. The best rotational speed is found to be dependent on both form and scale factors of Weibull wind speed distribution. Improvements in turbine pitch angle and rotational speed are found to increase generated energy up to four times, but the increasing factor is highly dependent on wind speed distribution: For the studied turbine, high-wind-speeds sites can benefit more from the adjustment of these parameters than low-speed ones. Keywords Wind turbine • BEM model • Pitch angle • Rotational speed • Wind distribution Greek symbols Pitch angle (°) Gamma function Turbine rotational speed (rad/s) Local flow angle (°) Solidity (-) Air density (kg/m 3)

No abstract

This study had the general objective to analyze the resulting values of hinge moment in the elevator for the PM-03 project, of an unmanned aerial vehicle, dedicated for participation in the SAE Aero Design 2020 Competition. From 2D CAD modeling of surfaces using Solidworks, the hinge moment was analyzed in Ansys Fluent after generating an appropriate mesh and adjusting the initial flow settings. The validation of the CFD analysis was performed by comparing experimental results from another study and using USAF Datcom data and correlations. The results obtained by CFD and USAF DATCOM diverge, however, those allows to correctly estimate the order of magnitude of the hinge moment, allowing an optimized selection of the servo motor for the project.

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Resumo: O uso de sistemas energia solar fotovoltaica cresce consideravelmente em todo o mundo. Pesquisas mostram que os módulos fotovoltaicos (FV) são consideravelmente afetados pela existência de poeira e sua deposição nas superfícies dos módulos, levando à redução da eficiência do sistema. Este trabalho tem como objetivo desenvolver um estudo, utilizando a Dinâmica dos Fluidos Computacional (CFD), sobre o uso de jatos de ar para promover o arrasto das partículas de poeira, removendo-as da superfície de módulos. Um modelo foi desenvolvido utilizando uma análise Euleriana, baseada em parâmetros físicos, a fim de descobrir a velocidade do ar para promover o arraste da poeira. Através do uso do software ANSYS CFX 17.1, foi possível realizar a montagem e simulação do modelo e adquirir dados importantes.

O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais. Conselho Editorial Ciências Humanas e Sociais Aplicadas Ciência, Tecnologia e Inovação: Desafio para um Mundo Global Capítulo 1

No abstract

The transmission of SARS-CoV-2 through contact with contaminated surfaces or objects is an important form of transmissibility. Thus, in this study, we evaluated the performance of a disinfection chamber designed for instantaneous dispersion of the biocidal agent solution, in order to characterize a new device that can be used to protect individuals by reducing the transmissibility of the disease through contaminated surfaces. We proposed the necessary adjustments in the configuration to improve the dispersion on surfaces and the effectiveness of the developed equipment. Computational Fluid Dynamics (CFD) simulations of the present technology with a chamber having six nebulizer nozzles were performed and validated through qualitative and quantitative comparisons, and experimental tests were conducted using the method Water-Sensitive Paper (WSP), with an exposure to the biocidal agent for 10 and 30 s. After evaluation, a new passage procedure for the chamber with six nozzles and a new configuration of the disinfection chamber were proposed. In the chamber with six nozzles, a deficiency was identified in its central region, where the suspended droplet concentration was close to zero. However, with the new passage procedure, there was a significant increase in wettability of the surface. With the proposition of the chamber with 12 nozzles, the suspended droplet concentration in different regions increased, with an average increase of 266%. The experimental results of the new configuration proved that there was an increase in wettability at all times of exposure, and it was more significant for an exposure of 30 s. Additionally, even in different passage procedures, there were no significant differences in the results for an exposure of 10 s, thereby showing the effectiveness of the new configuration or improved spraying and wettability by the biocidal agent, as well as in minimizing the impact caused by human factor in the performance of the disinfection technology.