90°弯管的三段弯曲式管形优化设计

Optimal Design of a Three-section-bending 90° Elbow Pipe

90°弯曲导管是航空管路系统的常见形式,但是传统一段弯曲方式,在高压高速流体流经时,会产生较大的涡流区,易引发流体噪音和管道结构振动。本文以肘形导管为例,研究了三段弯曲式管形优化设计。首先,根据涡流区和二次流的产生位置,提出三段弯曲方式的两种肘形导管设计方案。然后,以减小弯曲段和出口段涡流平均值为目标,采用线性近似约束优化算法(COBYLA),对三段弯曲肘形导管对应的4个管形参数进行尺寸优化。优化结果表明,三段弯曲方式涡流减少6.29%,截面二次流最大速率降低51.97%,流经弯曲段的压力损失降低12.64%。最后,讨论了管径、压力、流速等因素对优化结果的影响,给出最优管形参数的取值范围。该设计为航空管路的弯管设计和消脉减振提供了技术手段。

The 90°elbow pipe is commonly used for pipeline system.However,the traditional one-section bending produces large turbulence in high-pressure flow and high-velocity fluid,which can cause noise and vibration of pipeline structure.This paper takes an elbow pipe as example to study the optimal design of three-section-bending elbow pipe.Firstly,two pipe shape schemes are proposed according to the vortex generation zone and the secondary flow in curved pipe.In order to minimize the mean value of eddy currents at bend and exit sections,the constrained optimization and linear approximation algorithm is adopted to optimize the4parameters of the bending pipe that correspond to the three-section elbow bending catheter.The optimization results show that the three-section bending method reduces the eddy current by6.29%,the maximum velocity of the secondary flow decreases by51.97%,and that the pressure loss through the bending section decreases by12.64%.Finally,the influence of the factors such as diameter,pressure and flow velocity on the optimization results are discussed,and the range of the optimal pipe shape parameter is given.The design provides a theoretical basis for the design of bending section and pulse vibration elimination of an engine pipeline.