<p>We present direct numerical simulations of a novel concept for a microscale wind turbine, inspired in the mechanics of the autorotation of winged seeds. In this nature-inspired concept, the turbine blades have two degrees of freedom: the pitch and the elevation (or coning) angles. These allow the blade to vary its attitude with respect to the incoming velocity seen by the blade (i.e., the tip-speed ratio, <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\lambda \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>λ</mi> </math></EquationSource> </InlineEquation>). In order to validate this new concept, we perform numerical simulations of the coupled fluid–solid problem, solving together the Navier–Stokes equations for the fluid and the Newton equations for the rigid body (i.e., the blade). We characterize a preliminary nature-inspired single-blade rotor over a range of operational conditions (including both uniform and turbulent inflows), demonstrating the ability of the novel rotor to extract power at a very low Reynolds number (i.e., <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\textrm{Re}=240\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mtext>Re</mtext> <mo>=</mo> <mn>240</mn> </mrow> </math></EquationSource> </InlineEquation> based on the blade’s chord and the freestream velocity), significantly changing its attitude in response to different braking torques and tip-speed ratios. The rotor achieves a peak power coefficient of <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(C_{P,\max } = 0.026\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>C</mi> <mrow> <mi>P</mi> <mo>,</mo> <mo movablelimits="true">max</mo> </mrow> </msub> <mo>=</mo> <mn>0.026</mn> </mrow> </math></EquationSource> </InlineEquation> at <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\lambda \approx 2.0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>λ</mi> <mo>≈</mo> <mn>2.0</mn> </mrow> </math></EquationSource> </InlineEquation>. This peak value is unchanged between uniform and turbulence-perturbed inflows, demonstrating the robustness of the nature-inspired design. However, performance remains lower than that of fixed-blade configurations, showing that while the concept is feasible and stable, optimization of blade planform and mass distribution is essential to improve efficiency.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Aerodynamic performance and robustness of a nature-inspired concept for a microscale wind turbine

  • J. M. Catalán,
  • G. Arranz,
  • M. Moriche,
  • M. Guerrero-Hurtado,
  • M. García-Villalba,
  • O. Flores

摘要

We present direct numerical simulations of a novel concept for a microscale wind turbine, inspired in the mechanics of the autorotation of winged seeds. In this nature-inspired concept, the turbine blades have two degrees of freedom: the pitch and the elevation (or coning) angles. These allow the blade to vary its attitude with respect to the incoming velocity seen by the blade (i.e., the tip-speed ratio, \(\lambda \) λ ). In order to validate this new concept, we perform numerical simulations of the coupled fluid–solid problem, solving together the Navier–Stokes equations for the fluid and the Newton equations for the rigid body (i.e., the blade). We characterize a preliminary nature-inspired single-blade rotor over a range of operational conditions (including both uniform and turbulent inflows), demonstrating the ability of the novel rotor to extract power at a very low Reynolds number (i.e., \(\textrm{Re}=240\) Re = 240 based on the blade’s chord and the freestream velocity), significantly changing its attitude in response to different braking torques and tip-speed ratios. The rotor achieves a peak power coefficient of \(C_{P,\max } = 0.026\) C P , max = 0.026 at \(\lambda \approx 2.0\) λ 2.0 . This peak value is unchanged between uniform and turbulence-perturbed inflows, demonstrating the robustness of the nature-inspired design. However, performance remains lower than that of fixed-blade configurations, showing that while the concept is feasible and stable, optimization of blade planform and mass distribution is essential to improve efficiency.