Abstract In this study, a detailed analysis of hydrodynamic performance of a pumpjet propulsor (PJP) in different oblique inflow angles (β=0⁰, 5⁰, 10⁰, 15⁰, 20⁰, 25⁰, 30⁰, 40⁰) and different rotational speeds (n=3000rpm, 3600rpm, 4200rpm) is investigated numerically. The SST k-ω turbulence model and sliding mesh technology based on the Reynolds Averaged Navier-Stokes (RANS) method are employed. The structured grids are adopted to the whole computational domain. The grid independent inspection is carried out and verified. A ducted propeller (the Ka4-70 propeller in 19A duct) is selected to validate the numerical method by comparison of its results with experimental data. Based on the numerical method, it can be found that the propulsor efficiency decreased with the increasing of different β. The propulsor efficiency changes tinily in little oblique angle and decreases significantly when the oblique angle is larger than 20⁰. The thrust coefficient and torque coefficient of PJP are obtained. The increase of β has a negative impact on the balance performance of PJP. The pressure distributions of pressure and suction side of rotor blade with different β are analyzed. Owing to the influence of β, the pressure of the upper left region of rotor blade drops significantly. The enlargement of the local load on pressure side and the appearance and expansion of the low-pressure region on suction side occour at the bottom right region of rotor blade. The radial distributions of the axial velocity (Vz) and the tangential velocity (Vt) with different Span and β along the axial direction are investigated. The increase of β resultes in a severe oscillatory behavior of the flow velocity, which easily induces the occurrence of cavitation phenomenon and mechanical vibration. The velocity contours of the axial cross section with different β are presented. Due to the change of β, the flows are blocked by the flow-guide and duct, there are obvious high-velocity and low-velocity regions of the flows.

中文翻译：

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斜入流泵喷推进器流动特性的数值研究

摘要 本研究详细分析了泵喷推进器（PJP）在不同倾斜入流角（β=0⁰、5⁰、10⁰、15⁰、20⁰、25⁰、30⁰、40⁰）和不同转速（n=3000rpm）下的水动力性能。 , 3600rpm, 4200rpm) 进行了数值研究。采用基于雷诺平均纳维-斯托克斯 (RANS) 方法的 SST k-ω 湍流模型和滑动网格技术。整个计算域采用结构化网格。进行并验证了电网独立检查。选择管道螺旋桨（19A 管道中的 Ka4-70 螺旋桨）通过将其结果与实验数据进行比较来验证数值方法。基于数值方法可以发现，随着不同β的增加，推进器效率降低。推进器效率在小斜角时变化很小，当斜角大于20⁰时，推进器效率显着下降。得到了PJP的推力系数和扭矩系数。β 的增加对 PJP 的平衡性能有负面影响。分析了不同β下转子叶片压力侧和吸力侧的压力分布。由于β的影响，转子叶片左上区域的压力显着下降。压力侧局部载荷的增大和吸力侧低压区的出现和扩大发生在转子叶片的右下方区域。研究了不同跨度和β沿轴向的轴向速度(Vz)和切向速度(Vt)的径向分布。β 的增加导致流速的剧烈振荡行为，这容易诱发空化现象和机械振动的发生。给出了具有不同 β 的轴向截面的速度等值线。由于β的变化，流动被导流器和管道阻塞，流动存在明显的高速区和低速区。