斜流中七叶侧斜螺旋桨水动力及空泡性能研究

为研究七叶大侧斜螺旋桨斜流中的水动力及空化流场特性，基于DDES（延迟分离涡方法）建立了斜流中螺旋桨空化流场数值预报模型。在空化数 =2.024时对三套网格进行了不确定度分析，将斜流中螺旋桨（VP1304）水动力及空泡计算结果与试验结果进行了对比，验证了本文所建立数值模型具有较好的精度，然后对七叶大侧斜螺旋桨斜流中的水动力及空泡特性进行了计算。计算结果表明：斜流中螺旋桨推力和扭矩相对轴向流中均有明显下降，且随着进速系数的增大，下降幅度也逐渐增大，J=1.0时推力下降了82.1%，扭矩下降了47.6%；斜流中螺旋桨桨叶载荷呈周期性变化，随着进速系数的增大桨叶载荷极值变化率逐渐增大，J=1.0时，推力载荷极值变化率为163%，扭矩载荷极值变化率为100%；斜流中螺旋桨桨叶表面空泡形态十分不规则，螺旋桨旋转过程中伴随着严重的空泡融合、溃灭、脱落等现象，是桨叶表面载荷呈现脉动特性的重要原因，同时对螺旋桨的隐身性能十分不利。

Hydrodynamic Performance and Cavitation Characteristics of Seven Blade Propeller with Skew in Oblique Flow

A numerical simulation perdiction model of cavitation field in oblique flow was conducted based on the DDES(delayed detached-eddy simulation) to analyze the hydrodynamic performance and cavitation characteristics of a seven blade propeller with skew in oblique flow. The uncertainty analyzing was conducted through the three sets of grids under the condition of the cavitation number =2.024. The validation studies of the VP1304 propeller for hydrodynamic performance and cavitation in oblique flow were presented, and the calculation results were compared with the experimental results. It was verified that the numerical model established in this paper has good accuracy Then the hydrodynamic performance and cavitation characteristics in oblique flow was simulated. The results indicated that the thrust and torque of the propeller in oblique flow was significantly decreased relative to the axial flow, and as the advance coefficient increased ,the decline gradully increased. As the advance coefficient J=1.0, the thrust dropped by 82.1% and the torque is reduced by 47.6%. The blade load in oblique flow changed periodically, and the change rate of the extreme value of the blade load gradually increased with the increase of the advance coefficient. In light load condition(J=1.0), the extreme thrust load change rate was 163%, and the extreme torque load change rate was 100%. The cavitation on the propeller blade in oblique flow was very irregular. The rotation process of the propeller was accompanied by serious cavitation rusion ,collaspse and shedding which was an important reason for the pulsating characteristics of the blade load and was bad for the stealth performance of the propeller.