Influence of geometric parameters of nacelle pressure relief door on flow characteristics
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摘要:
运用CFD仿真计算了不同倒圆角、铰链、长宽比的泄压门排放系数,并从流动层面深入剖析了以上几何参数对流动特性的影响机理,其结果可供短舱泄压工程设计参考。研究显示,倒圆角仅略增大排放系数。此外,不同铰链泄压门的排放特性不同,鹅颈式优于枢轴式和合页式,原因是铰链安装形式导致外侧迎流面的流动及出流通道变化。鹅颈式出流通道最大,部分气流从安装缝隙流出,故出流能力最强;合页式外部来流冲击门板后向两侧绕流而阻挡出流,故排放能力最弱;枢轴式外侧来流对出流引射作用较合页式强,但因出流通道较鹅颈式小,故出流能力小于鹅颈式。长宽比大时排放系数大,原因是长宽比大时外侧来流向门板两侧绕流减弱,出流处易形成卷吸涡而增强出流。
Abstract:A method of CFD simulation was used to calculate the discharge flow ratio of different fillets, hinge forms, and aspect ratios. Impact mechanism of different pressure relief flow was also researched. These results could support the engineering design of nacelle pressure relief door. The research showed that the fillet only increased the discharge flow ratio slightly. In addition, pressure relief doors of different hinges had different discharge flow ratios, the goose neck type was superior to the pivot hinge type and the page hinge type, due to the hinge installation which caused the changes of the outside heading flow and the exhaust channel. Specifically, the pressure relief door with goose neck hinge had the strongest discharge capacity owing to the largest exhaust channel, and some air flowed from the installation slot. However, the external flow hit the page hinge type and then blocked the flow from both sides, which caused the weakest discharge capacity. The external flow of the pivot hinge type had stronger ejection effect on the discharge flow, causing stronger discharge capacity than the page hinge type. However, the discharge capacity of the pivot hinge type was weaker than the goose neck type because of the smaller exhaust channel. The pressure relief door with larger aspect ratio had larger discharge flow ratio, due to the reduced winding flow of the external air and the increased exhaust flow owing to the coiled vortex.
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Key words:
- nacelle /
- pressure relief door /
- fillet /
- aspect ratio /
- hinge /
- discharge flow ratio
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表 1 不同铰链形式泄压门的排放系数(θ =38.6°)
Table 1. Discharge coefficient of pressure relief door with different hinge lines (θ =38.6°)
铰链形式 排放系数 鹅颈式 0.6817 合页式 0.4487 枢轴式 0.5002 表 2 不同长宽比的泄压门的排放系数(θ =30°)
Table 2. Discharge coefficient of pressure relief door with different length ratios (θ =30°)
长宽比 排放系数 0.5 0.588 1.0 0.682 1.5 0.826 -
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