影响桨毂帽鳍助推效率的主要参数

Discussion of main parameters influencing assistant thrust efficiency of propeller boss cap fins

为了分析影响毂帽鳍的水动力性能的各种因素,采用计算流体力学软件对粘性流场中毂帽鳍的敞水性能进行了计算研究,模拟了某型毂帽鳍在不同参数和不同进速系数下的效率变化曲线。通过对计算结果的对比分析可以得出:毂帽鳍的半径最好不要大于螺旋桨直径的1/3,否则会产生过大的反向推力,造成附加推力的下降;毂帽鳍要处于合适的安装角度范围内,才能使得它对螺旋桨的综合效率最大;轴向位置也存在一个最佳值,过大则桨对毂帽鳍的诱导速度会随之降低,而过小桨叶和鳍片之间的干扰会造成扰流,导致效率的下降。同时,从整个桨的静平衡和回收效率考虑,选定鳍叶数和桨叶数相同较为合适。

Aiming at various factors that influence hydrodynamic performance of propeller boss cap fins,CFD software was used to calculate the open water performance of fins in viscous flow.The efficiency curves were gained by simulating some types of fins at different parameters or advance coefficients.The compare results show that it would be better that the fin′s radius is not greater than one-third of propeller′s diameter;otherwise,the much bigger reversed thrust would reduce additional thrust.Only in a proper fix angle range,can the propeller boss cap fin have the highest competitive efficiency to screw.There is an optimum in axial position too.If the value is much bigger,the induced velocity from screw would be reduced;whereas,the interference between blades and fin pieces may arouse burble that would reduce the efficiency.Moreover,considering the static balance of whole propeller and recovery efficiency,the number of fin pieces and blades should be the same.