【作者】 陈朝辉；

【导师】 刘艳；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2009， 硕士

【摘要】 船体、螺旋桨、主机三者匹配合理时,船舶的推进效率高,能耗低。这是船舶设计者和船舶营运者应该追求的目标。对于运营多年的旧船,由于船体出现污损、螺旋桨表面受到腐蚀及主机因磨损而导致功率下降等原因,螺旋桨会出现负荷过重现象,进而导致船—机—桨三者的匹配点偏离设计工况时的最佳匹配点。为了使主机能在额定工况附近工作,需要调整船—机—桨三者的匹配情况。在船、机已定的情况下,可通过改造螺旋桨的方法实现。改造螺旋桨既简单又可行的办法是边缘修割,通过切割螺旋桨边缘改变其负荷进而改善其推进性能。本论文采取切割桨叶直径和随边的方法,通过试验和理论研究改造后的螺旋桨的敞水性能,为实际螺旋桨改造提供技术支持。本论文通过对系列切割叶梢后的MAU4-50型螺旋桨的敞水试验,获得了该桨的水动力性能参数。结果表明在相同的进速系数下,随着切割量增大,推力系数和转矩系数也随着增大,但是在小于最佳效率的范围内,敞水效率却随着切割量增大而减小。同时得到了直径相对切割量与螺旋桨转速相对改变量的关系图谱。根据系列切割随边后的KMM4-66桨敞水试验数据,得出了和理论分析一致的结果即在相同的进速系数下,推力系数、转矩系数和敞水效率η随着盘面比的降低而降低。同时给出了盘面积相对切割量与转速相对改变量的关系图谱。为了探索理论预报螺旋桨敞水性能的准确程度和可靠程度,论文采用了升力面理论计算不同切割情况下的螺旋桨的水动力性能。与试验结果比较表明升力面理论预报的敞水特性曲线的变化规律与试验得到的一致。同时也采用CFD方法对MAU型螺旋桨进行数值模拟,探讨升力面与CFD两种方法在预报螺旋桨精度问题。通过比较看出,CFD方法预报螺旋桨敞水性能比升力面理论要精确。这固然是因为粘流理论处理的是实际流体,而升力面是基于势流理论。同时也可能是升力面在边界条件和尾涡模型等方面简化所致。总体来看,升力面理论和CFD方法都能很好的应用于螺旋桨的削边改造。更多还原

【Abstract】 It will be of high propulsive efficiency and low energy consumption for a ship when the hull, engine and propeller match well. This should be what naval architects and ship operators go in for. After many years of operation, the propeller may be overloaded due to some reasons such as fouling of the hull, ageing of the engine and corrosion of the propeller. As a result, the designed optimal matching point between the hull, engine and the propeller will be offset. When the hull and engine are fixed, it is the only optional solution to modify the propeller in order to make the engine work near the rated condition.It is an easy and feasible solution to modify the propeller by cutting its edge. In this paper, it is carried out to study on the two propellers which are cut on the blade tip and the trailing edge respectively by tests and theoretical calculations, which offers the technical support for the modification of the propeller in the practice.The open water performance of the MAU4-50 propeller was obtained by carrying out the open water test with the propeller being cut on the blade tip at different diameters in this paper. The results from the tests show that the thrust coefficient and torque coefficient are increasing with the increase of the cutting amount at the same advance coefficient, while the open water efficiency is decreasing. As a result, the relationship between the relative cutting amount of the diameter and the relative variation of the MAU propeller speed in form of charts are derived from the experimental data. The results from the tests of the KMM4-46 propeller which was cut on trailing edge at different chord lengths show that the thrust coefficient, the torque coefficient and the open water efficiency are decreasing with the decrease of the impeller solidity ratio, and the relationship between the relative variation of KMM propeller speed and the relative cutting amount in the form of charts are also derived from the results.The lifting surface theory is carried out to calculate the open water performance of the two propellers under different circumstances in order to study the accuracy and the feasibility of predicting the open water performance of the propeller in theoretical way. The same changes of open water performance of the two propellers occur in two theoretical ways versus the tests. Meanwhile, the computational fluid dynamics method is also used to predict the open water performance of MAU propeller. Comparison results show that predictive accuracy of numerical simulation study is higher than that of the lifting surface theory. The reason is that the viscous flow is dealt with the real flow while the lifting surface theory is based on the potential flow. It may be due to the simplification of boundary conditions and wake model. On the whole, the two methods are well used to predict open water performance of propellers.更多还原