风机叶片翼型大攻角下气动性能的数值分析

NUMERICAL ANALYSIS OF WINDMILL BLADE AERODYNAMIC PERFORMANCE AT LARGE ATTACK ANGLE

以NACA早期的翼型Clark Y为研究对象,采用数值模拟方法,对该翼型在20°攻角下的气体绕流情况进行稳态和瞬态计算,得到翼型的气动性能;通过对比分析稳态、瞬态计算结果,得出Clark Y翼型在20°攻角下的气体绕流运动本质上是一种具有涡街形式的准稳态物理现象,如果强制给它一种稳态模型,则计算将会出现收敛不好、结果不准确的问题。强调了在采集翼型大攻角下的升力阻力系数等参数时,必须注意采取非定常结果的合适时间段的平均值。

The steady and the unsteady calculations through simulation were done based on the Clark Y of NACA at 20 attack angle, and the aerodynamics performance of Clark Y airfoil was obtained. Through comparing and analysis the steady and the unsteady results, it is found that the flow along the Clark Y airfoil at 20attack angle is a quasi-steady phenomenon with the wake vortex, and the resuh will not be convergence or wrong if the calculation was done with steady model. At the large attack angle, getting accurate lift and drag coefficient should average the transient result in a proper time range.