斜流角对半浸桨叶剖面入水的水动力特性分析

Analysis of hydrodynamic characteristics of oblique flow angle to semisubmerged blade profile

为了分析自然通气状态下斜流角对半浸桨的水动力特性的机理问题,本文对无因次半径为0.7处的841-B型半浸桨的杯型剖面进行建模。通过求解RANS方程模拟杯型剖面入水过程的同时,结合标准k-ε湍流模型、流体体积方法以及重叠网格技术,建立可靠的数值方法,并在此基础上研究不同斜流角工况下半浸桨杯型剖面的水动力特性,分析了不同斜流角工况下的半浸桨杯型剖面的自由液面形式、通气腔形式、流场形式以及表面压力分布。研究结果表明:增大半浸桨杯型剖面的斜流角,会对其入水过程的通气现象起到一定的促进作用,此外,由于增大半浸桨杯型剖面的斜流角会间接增大浸深,进而使得半浸桨杯型剖面受到的横向力系数以及垂向力系数有所增大。在半浸桨的工程应用过程中,要着重考虑传动轴以及工况的改变对其斜流角的影响机理。

To analyze the mechanism of the hydrodynamic characteristics of oblique flow angle to surface piercing propeller under natural ventilation,the cup section of an 841-B surface piercing propeller with a dimensionless radius of 0.7 was modeled.A reliable numerical method was established by solving the RANS equation to simulate the water entry process of the cup section combined with standard k-εturbulence model,VOF method,and overlapping grid technique.On this basis,the hydrodynamic characteristics of the surface piercing propeller cup section under different oblique flow angles were studied,and the free liquid surface form,ventilation cavity form,flow field form,and surface pressure distribution of the surface piercing propeller cup section under different oblique flow angles were analyzed.Results show that increasing the oblique flow angle of the surface piercing propeller cup section will promote the ventilation phenomenon in the water entry process.In addition,increasing the oblique flow angle of the surface piercing propeller cup section will indirectly increase the immersion depth.As a result,the transverse force coefficient and vertical force coefficient of the surface piercing propeller cup section will increase further.Therefore,the influence mechanism of the transmission shaft and working condition on its oblique flow angle should be considered in the engineering application of surface piercing propeller.