基于CFD的船舶自流冷却系统进水口形式优化

Optimization of the Types of Water Inlets in Marine Scoop Cooling Systems Based on CFD(Computational Fluid Dynamics)

船舶自流冷却系统进水口的结构对船舶航行和凝汽器冷却效果具有显著影响。本文利用软件Fluent采用标准k-ε模型对船舶自流冷却系统不同形式进水口进行了数值模拟,从流量、航行阻力以及对尾流场的影响等方面分析了不同进水口形式的流动特性。结果表明:相同管径时,直管口能获得较大的流量并且对外流场的影响最小,同时进水口的外伸长度直接影响流量和航行阻力的大小,但是对尾流的影响却是与出水口相耦合,因此进水口的设计应该结合出水口进行。

The structure of water inlets of a marine scoop cooling system has a significant effect on the navigation of ships and the cooling efficiency of condensers.A numerical calculation is conducted for different types of water inlets of marine scoop cooling systems by the use of software Fluent and through the adoption of a standard k-ε model.The flow characteristics of different types of water inlets are analyzed from such aspects as flow rate,navigation drags and the impact of wake flow fields.The results show that with a same tube diameter,the straight tube inlet can provide a relatively large flow rate and cause a minimal effect to the external flow field.Meanwhile,the extended length of the water inlets can directly influence the flow rate and the magnitude of navigation drags.However,the impact to the wake flow is closely related to water outlets.Hence the design of water inlets should be conducted in conjunction with that of water outlets.