导管桨内部流场的数值计算

Inner flow field calculations for ducted propellers

为研究导管螺旋桨的内流场特征,用面元法计算了导管桨中螺旋桨和导管的诱导速度.导管上采用余弦布置轴向面元、均匀布置周向面元;螺旋桨叶片上径向和弦向均采用余弦布置方法.由于导管和螺旋桨之间存在相互干扰,在研究中采用了迭代计算方法.当迭代计算结果收敛后,可以求出导管及螺旋桨表面的速度势和源汇强度,进而根据蒙瑞诺解析公式计算导管桨的内部流场.在研究导管桨内部流场的过程中,计算了导管桨的水动力性能.对桨前后不同位置导管桨的内部流场进行分析,并将其和敞水情况作了比较.计算结果表明,导管的存在使得螺旋桨的诱导流场变小,螺旋桨的存在使得导管的诱导流场变大.

The velocities induced by propellers and ducts were calculated in order to study the inner flow fields of ducted propellers. On the duct surface, panels along the axial direction were arranged by the cosine method and along the circumferential direction by the mean method. On the surface of the blade, panels along the span direction and the chord direction were both arranged by the cosine method. An iterative calculation method was used to derive the interaction between the duct and the propeller. The strength of the dipole and vortexes on the surface of the duct and the propeller were obtained when the calculation converged, then the inner flow fields of the ducted propellers were calculated by the Morino Method. The hydrodynamic performance of the ducted propellers was then established in the process of calculating the inner flow field.＂ The induced velocities at the back or front of the propeller were analyzed and compared with open water conditions. The results indicated that the velocity induced by the duct is smaller because of the influence of the propeller, while the velocity induced by the propeller is larger because of the influence of the duct.