【摘要】 奇点分布法是计算确定轴流叶轮叶片流面翼型骨线的一种重要方法,此方法要求在骨线上布置一系列连续涡以代替翼型产生一符合给定叶轮外特性的平面诱导速度场,并最终形成满足要求的微弯翼型骨线。确定正确的骨线漩涡密度函数是实现这一目的的基础。通常定义的密度函数实际只适应轴流式转轮翼型骨线的流动特征。提出了与传统密度函数不同的适合叶轮翼型边界条件的漩涡分布函数,以平面势流理论证明了这一新规律的合理性:在涡层上各点法向合成速度为零,体现了由此产生的翼型骨线的不可穿透性;计算所得的涡层前、后缘点分别满足平面均匀流绕流翼型的库达-恰布雷金定理。更多还原

【Abstract】 Singular point distribution method is an important approach in axial blade design for computing and shaping midline of axial impeller airfoils on a developed flow plane. The principle involved in this method is to place continuous vortices along the midline to replace airfoils,to induce a plane velocity field meeting the requirement of specified pump performance,and,finally, to form the required microbending airfoil midline. A proper strength function of vortex sheet is a primary to realize this object.It is found that the commonly defined strength function is only suitable for flow conditions in runner plane airfoils. We presented a new vortex strength function differing from the traditional one and justified the reasonableness of the new theorem by potential flow theories: the resultant velocity normal to the sheet is zero,in compliance with the fact that the flow can’t penetrate the solid airfoil; the computed velocities at the front and rear points of the airfoil in a uniform stream indicate these two points are in agreement with Kutta-Chaplygin conditions. The paper formulates a new way for axial airfoil design.更多还原