港作拖船全回转推进器防护格栅设计

针对港作拖船在复杂水域作业时推进器极易遭遇杂物碰撞与吸附,损坏推进系统,影响推进效率等问题,设计一套类翼型截面式推进器防护格栅装置。对不同的格栅环肋与来流方向的夹角(攻角)进行分析计算,将格栅对推进器效率的影响等效为推进器在流场中的总阻力变化,确定一组最合理的攻角,在提供最大防护性能的前提下,将格栅对推进效率的影响降到最低。结果表明,当内、外环肋攻角分别取6.5°、10°时,阻力增加率较小,流场变化平稳,符合设计指标要求,并能对推进器进行有效防护。

Design of port tug Z propeller protection gird

The port tug propeller working in complex waters is easy to encounter debris collision or adsorption so as to damage the propulsion system and affect the propulsion efficiency. For the above problem, a propeller protection gird is designed with wing type section. The angles (attack angles) between different grid ring ribs and the incoming flow direction are analyzed and calculated, and the effect of the gird on the propeller efficiency is equivalent to the total resistance change of the propeller in the flow field. A set of the most reasonable attack angles is determined to minimize the effect of the grid on the propeller efficiency while providing maximum protection. The results show that when attack angles of inner and outer ring ribs take 6.5° and 10°, respectively, the resistance increase rate is small, and the flow field changes smoothly, which meets the requirements of the design index, and can effectively protect the propeller.