基于舵机能力验证要求的舵系优化设计

Optimization design of rudder unit based on requirements of steering gear capacity verification

在IACS统一解释文件UI SC246 Rev.1提出根据非满载试航船舶操舵试验结果对满载航行状态船舶舵机能力进行验证的换算方法之后,相当一部分采用半悬挂舵的船舶出现了无法按该方法通过舵机能力验证的状况。为解决上述问题,本文基于常规船型半悬挂舵的3种典型布置方案,通过设计相同的舵面积和不同的几何外形,得到3个计算模型,利用计算流体力学(CFD)方法对各方案的全浸没和部分浸没状态分别进行计算分析。计算结果表明,舵叶平衡比对舵杆水动力扭矩存在直接影响,适当大的舵叶平衡比设计可以显著降低舵叶全浸没状态和部分浸没状态的舵杆水动力扭矩。基于此结论,对某型未能通过换算验证的船舶舵系进行优化设计,适当增大了舵叶平衡比。后续船试航结果表明,舵机能力验证满足UI SC246 Rev.1的要求,确认了CFD计算结论的正确性,为以降低舵杆水动力扭矩为目标的舵系优化设计提供了理论和实践依据。

In the IACS Unified Interpretation Document UI SC246 Rev.1,the verification of the steering gear capacity with the ship at the full load condition is proposed,which based on the results of the steering test with the vessel not at the deepest sea going draught.A considerable number of ships using the semi-balanced rudder appeared to be unable to comply with the requirements.In order to solve this problem,three typical layout schemes of the conventional semi-balanced rudder are obtained by designing the different geometrical shapes with the same rudder area,and the computational fluid dynamic(CFD)method is used for each scheme.Full immersion and partial immersion rudder are calculated and analyzed separately.The calculation results show that the balance ratio of the rudder as a direct effect on the hydrodynamic torque of the rudder stock.The appropriate rudder blade balance ratio can significantly reduce the hydrodynamic torque of the rudder stock when the rudder blade at full immersion state and partial immersion state.Based on conclusions above,an optimized design for rudder unit which failed to meet the requirements is performed,and the rudder blade balance ratio is appropriately increased.The trial result of subsequent sister ship shows that the steering gear capability verification meets the requirement of UI SC246 Rev.1,which confirmed the correctness of the CFD calculation conclusion,and provided theoretical and practical basis to the rudder system optimization design aimed at reducing the rudder hydrodynamic torque.