Powertrain assessment of wind and hydrokinetic turbines with diffusers
| Autor: | Taygoara Felamingo de Oliveira, Alexandre Luiz Amarante Mesquita, André Luiz Amarante Mesquita, Antonio Cesar Pinho Brasil Junior, Jerson Rogério Pinheiro Vaz |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Small wind turbine
Renewable Energy Sustainability and the Environment Rotor (electric) Powertrain 020209 energy Energy Engineering and Power Technology Rotational speed 02 engineering and technology Mechanics Turbine law.invention Diffuser (thermodynamics) Physics::Fluid Dynamics Fuel Technology 020401 chemical engineering Nuclear Energy and Engineering law 0202 electrical engineering electronic engineering information engineering Environmental science Torque 0204 chemical engineering Friction torque |
| Zdroj: | Energy Conversion and Management. 195:1012-1021 |
| ISSN: | 0196-8904 |
| DOI: | 10.1016/j.enconman.2019.05.050 |
| Popis: | A growing interest has been devoted to turbines with diffusers, which induce a pressure drop downstream of the turbine to accelerate the fluid in the axial direction. This effect increases the axial aero- or hydrodynamic load on the turbine powertrain, such that frictional torque presents a challenge to turbine starting. Hence, this work is concentrated on how a diffuser can affect the dissipative torque of a wind or hydrokinetic turbine, in which the increased axial load and starting torque need to be considered. The approach uses a quasi-steady Blade Element Momentum model, adapted to consider the action of a diffuser, to predict instantaneous aerodynamic torque and power. The mass-moment of inertia of the entire system is taken into account, as well as the frictional losses in the bearings. As the diffuser affects the axial load on the rotor blades, the dissipative torque can undergo relevant variations. The Stribeck effect on the starting behavior of a small wind turbine is analyzed in order to evaluate the influence of the diffuser on the minimal flow velocity necessary to start rotating the turbine. The rotational speed and power output of a shrouded hydrokinetic turbine with a 10 m diameter are computed and compared to those of a bare turbine; at steady-state, a rotational speed 20% higher than that of the bare turbine is achieved, generating about 40% more net energy despite increased powertrain losses. |
| Databáze: | OpenAIRE |
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