调距桨锁轴拖带工况最小拖桨阻力和水动力矩

Research on Minimum Additional Drag and Hydrodynamic Moment of Locked Controllable Pitch Propeller

采用计算流体力学方法,对某典型5叶调距桨锁轴工况拖桨阻力以及相应的水动力矩随螺距和进流速度的变化特性进行了数值计算,分析了这些特性的流体力学机理.数值计算基于有限体积法,通过数值求解螺旋桨周围三维黏性不可压缩流场RANS方程来模拟螺旋桨在各种工况下的流动特性.计算结果表明:来流速度相等时该调距桨在最大正车螺距时拖桨阻力最大,其幅值约占同航速下船体阻力的80%,水动力矩也最大;在最大倒车螺距时拖桨阻力最小,其幅值约占同航速下船体阻力的50%,水动力矩比最大正车螺距时显著减小;零螺距时拖桨阻力大小居中,而水动力矩最小,接近为零.上述结论可为船舶动力装置部分桨工况时联控曲线的设计和锁轴机构的设计提供理论参考.

The optimal pitch of a locked controllable pitch propeller corresponding to minimal additional drag and minimal hydrodynamic moment was investigated by means of computational fluid dynamics for a ship that is propelled by part of propellers.A typical five-blade controllable pitch propeller was calculated numerically to gain the characteristics of additional drag and hydrodynamic moment as functions of its pitch and advance velocity.The numerical calculations are based on finite volume method.The RANS equations of the 3D incompressible viscous flows are solved iteratively to simulate the flow behavior around the propeller.The calculation results show： ① The additional drag of the locked propeller is maximal when the propeller is set on maximal ahead pitch,which accounts for about 80% of the hull resistance at the same speed.The value of hydrodynamic moment also reaches maximum;②The additional drag of the locked propeller is minimal when the propeller is set on maximal astern pitch,which accounts for about 50% of the hull resistance at the same speed.The hydrodynamic moment decrease markedly compared with the maximal ahead pitch;③At zero pitch the additional drag lies between maximal ahead pitch and maximal astern pitch,and the hydrodynamic moment is very small which comes close to zero.These conclusions are helpful for marine engineers not only to determine joint control curve of the propulsion plant for the operating condition that the ship is propelled by part of propellers,but also to design the shaft brake rightly.