基于面元法的分布式涵道推进系统进气道优化设计

Optimization Design of Inlet for Distributed Ducted Fan Propulsion System Based on Panel Method

关键词:  面元法  分布式推进  进气道  优化  畸变

Key words:  Panel method  Distributed propulsion  Inlet  Optimization  Distortion

摘要:

分布式涵道推进系统被认为是一种高效率的动力布局形式，其中进气道如何使气流低损失地快速过渡到数个圆形截面的涵道风扇进口是一个亟需探索的设计问题。以分布式涵道推进系统进气道过渡段为研究对象，基于面元计算方法，发展了一种进气道内流动的快速数值预测手段。应用所发展面元法数值方法结合进气道的超椭圆参数化方法、自适应优化算法，建立了分布式涵道推进系统进气道的无经验优化设计方法。以某型悬停状态的分布式涵道推进垂直起降飞行器为例，使用该设计方法实现了从无圆滑过渡的简单初始几何到气动指标符合优化预期的光顺几何的优化设计。基于RANS的三维数值分析表明：所优化设计的进气道相比于初始几何总压畸变系数（DC）从0.0086降低到0.0067，低于基于经验设计的参考几何（DC=0.0073），且流场无明显分离及旋涡，确认了这种具有高时间效率的无经验设计方法的有效性。

Abstract:

The distributed ducted propulsion system is considered to be a kind of high-efficiency aerodynamic layout. How the intake makes the flow quickly transfer to several circular cross-sections for ducted fans is a design problem that needs to explore urgently. Taking the transition section of the inlet of the distributed ducted propulsion system as the research object， a fast-numerical flow prediction method for the inlet is developed based on the panel method. Combined with the hyperelliptic parameterization method and adaptive optimization algorithm， a nonempirical optimization design method for the inlet of distributed ducted propulsion system is established. In the case of designing a distributed ducted fan propulsion used in a vertical take-off and landing aircraft， this method is used to achieve an optimal design changing simple initial geometry to a smooth geometry that meets the optimization expectations. The numerical solver based on RANS is used to verify the aerodynamic properties of the optimized geometry. Compared with the initial geometry， the optimized inlet’s total pressure distortion coefficient （DC） is reduced from 0.0086 to 0.0067， which is lower than the baseline geometry based on empirical design （DC=0.0073）， and there are no obvious separation and vortex in the flow field， which confirm the effectiveness of the nonempirical design method with high time efficiency.