钙质生物污损对船舶阻力和能效的影响

Effect of the ship frictional resistance and performance due to the calcareous biofouling

采用Schultz对钙质生物污损状况的粗糙度量化和分级,确定了钙质生物污损导致的船舶表面粗糙度函数。基于边界层相似定律,根据相应的船舶表面钙质生物污损粗糙度函数,采用自编的程序,计算和分析了5艘实例船舶在不同钙质生物污损下的阻力增加与船舶长度及速度之间的关系,绘制了相应的实际阻力增加速度曲线。利用实际的阻力增加-速度曲线预测了实例船舶在不同钙质生物污损状况对船舶的摩擦阻力增加和能效增加的影响。结果表明,在重度钙质生物污损下,5艘实例船舶的阻力系数增加为161%~235%,其中的商船,集装箱船和油轮的有效功率增加分别为109%和82%。

According to Schultz′s rough quantification and classification of the biofouling conditions,the roughness functions of a range of fouling conditions were determined.Based on the boundary layer similarity law analysis,following the roughness functions and u sing an in-house code,the resistance increases of the five example ships for varying ship lengths,ship speeds and fouling conditions were analyzed and calculated.The corresponding actual added resistance-speed relationship curves were obtained.The increasing impact on the ship frictional resistance and performance of the example ships with the different calcareous biofouling conditions were investigated and predicted using the obtained actual added resistance-speed relationship curves.The results showed that the percentage increases in the frictional resistance for the five example ships due to heavy calcareous fouling were in the range of 161%~235% and the increases in the effective power due to the surface conditions for the container ship and the oil tank were predicted to be up to 109%,and 82%,respectively,under heavy calcareous fouling condition.