叶片内部蒸汽冷却的数值模拟

在某燃气轮机第二级导向叶片的基础上,对叶片内部进行了设计并采用内部蒸汽冷却方式.采用非结构化网格和Realizable k-ε紊流模型,对同时带15°,30°和45°肋的叶片内外流场以及叶片本身进行了三维热耦合的定常数值模拟.热耦合采用在流固耦合面的热对流和固体导热来实现.内部冷却介质选用比空气热容大,粘度低的水蒸汽.结果表明:带肋的通道流场非常复杂,扰流肋的存在使各壁面的换热都得到了增强,相对于光滑通道换热显著,有明显的冷却痕迹,冷却效果明显;采用蒸汽冷却比用空气冷却效果要好;压力面温度普遍低于吸力面温度. 

Numerical simulation of a steam-cooled vane

The steam cooling method was applied in this paper to study the design and characteristics of cooling structure for a vane of gas turbine.The unstructured meshes and realizable k-ε turbulence model were used to study the flow behaviors both inside and outside the grid-ribbed rectangular channel with 15°,30° and 45° rib-roughened wall through 3-Dcoupled numerical simulation.Coupling heat exchange was achieved by heat transfer and solid conduction on the coupled-side of fluid and solid.The cooling medium was steam which had greater Cp and lower viscidity than air.Results show that the flow of the passage is very complex.Heat transfer is enhanced because of the ribs.Ribbed wall has better heat transfer effect than the no rib wall and the cooling effect is obvious.Cooling effect is better by using the steam than by using the air.The numerical result shows the temperature on pressure surface is lower than suction surface.