一体化节能推进装置定常水动力性能的数值模拟分析

Steady hydrodynamic performance simulation of integrative energy-saving propulsion system

为了对比和分析一体化节能推进装置的节能效果,采用粘流计算流体力学方法计算了普通桨舵系统和一体化推进系统的定常水动力性能.采用分区域划分网格方案,将计算域分解为2个区域,内区包含螺旋桨,整个区域采用结构网格,螺旋桨表面及近后方流场网格局部加密.通过将桨舵系统的推力、扭矩、效率计算值与势流计算结果及试验值进行对比验证了数值方法的可靠性.同时,研究了2个推进系统下水动力性能及桨舵表面受力分布的变化规律,通过分析认为:一体化节能推进装置通过增大螺旋桨推力,减小舵的阻力,提高了桨舵系统的效率,效率增值约为3%～8%;同时与普通舵压力比较,设计舵导边位置的压力集中区面积减小,舵中部压力分布更加均匀,舵剖面压力系数分布平缓,使得舵的水动力性能改善.

In order to effectively study energy saving efficient integrative energy？saving propulsion systems, the com？putational fluid dynamics （CFD） method was used. The CFD method allows the numerical simulation of the steady hydrodynamic performance of the common propeller？rudder system and integrative energy？saving propulsion system. A sub？domains mesh partition method was adopted, and the computation domain was separated into two sub？do？mains, in which screw propeller was included and hexahedral elements were used in all domains. The mesh was lo？cally refined on the propeller surface and near the wake flow field. Hydrodynamic performance parameters such as thrust coefficients, torque coefficients and efficiency were calculated and compared with the results of potential flow methods and experimental data. The results showed that numerical results agreed well with the other two results, which validated the reliability of the numerical method. At the same time, the hydrodynamic performance and sur？face pressure distribution of the two propulsion systems were examined. It can be concluded that the efficiency of integrative energy？saving propulsion systems which had 3%~8% increment was improved through increasing propel？ler thrust and reducing rudder drag. In comparison with the pressure distribution of common rudder, the area of pressure focus domain was reduced in leading side of design rudder, the pressure distribution of rudder center was changed with more uniformity, and the pressure coefficient of the rudder section was more flat, thus, making the hydrodynamic performance of design rudder more ameliorated.