翼型风帆助推船舶EEDI计算方法研究

Study on EEDI Calculation Method for Wing Sails Assisted Ship

针对新实施的指南文件计算加装风帆的船舶能效设计指数(EEDI)主机负荷可能超限等情况,采用以固定航速为主、固定功率为辅的思路,研究一种基于4自由度直航操纵运动数学模型和全球主要海运航线的风况概率统计数据,考虑螺旋桨推力、扭矩及推进效率等随进速的变化以及主机油耗随负荷的变化,得到船舶加装翼型风帆后的EEDI计算方法。结合风洞、水池试验结果以及构建的与有义波高、周期相关的波浪漂移力数据库,考虑辅机和操帆功耗,计算翼型风帆组的EEDI贡献度,并与采用指南方法的计算结果进行对比。结果表明指南方法会高估翼型风帆组的EEDI贡献度。该研究可为加装风力助推系统的船舶进行EEDI计算分析提供参考。

Calculation method of EEDI for a ship with wing sails was developed in steady sailing with fixed speed and fixed power,which is based on the mathematical model of four degrees of freedom and probability statistics.EEDI calculation method,provided in the newly implemented guidance document,is applied with considering change of propeller thrust,torque,propulsion efficiency,fuel consumption coefficient and possible overload of the main engine.Wind forces and hydrodynamic forces of the wing sails assisted ship were obtained by the wind tunnel and water tank model test respectively.Wave drift forces in the model were constructed as a database related to the wave height and the period.EEDI contribution of the wing sails was calculated by taking into account the power consumption of the auxiliary engine and sails handling respectively.The results were also compared with the results based on the method provided by guidance document.The results show that the method provided in guidance document will overestimate the EEDI contribution of wing sails.The research work can be used for calculation and analysis of EEDI of ships equipped with wind propulsion system.