基于响应面模型的波瓣混合排气系统近似模型研究

发布时间：2018-01-23 05:32

本文关键词： 波瓣混合排气系统波瓣高宽比多项式响应面模型波瓣性能参数波瓣结构参数　出处：《推进技术》2016年06期 　论文类型：期刊论文

【摘要】：基于Navier-Stokes方程组对涡扇发动机波瓣强迫混合排气系统进行了数值模拟,获得了波瓣尾缘位置内、外涵流通面积与内、外涵入口位置流道截面积相等时,不同波瓣高宽比对波瓣混合排气系统性能参数以及结构参数的影响规律。并以此为基础,采用不同阶数的多项式响应面模型建立了波瓣性能参数随高宽比变化的近似模型。在多项式响应面模型拟合精度方面,相对于二阶、三阶多项式响应面模型,四阶多项式响应面模型能够较好地反映出热混合效率、总压恢复系数、排气系统相对推力、波瓣混合器相对质量随波瓣高宽比的变化规律,其拟合结果与数值仿真结果也相差极小。在波瓣高宽比对混合排气系统性能影响方面,在混合排气系统出口截面处,随着波瓣高宽比的增加,热混合效率在"波浪状"的变化规律中整体呈现出"增大-减小"发展趋势,总压恢复系数则呈现出"缓慢增加-迅速降低-增加-迅速下降"的复杂变化趋势;在排气系统相对推力方面,当高宽比大于3时,虽然相对推力呈现出波浪形的变化趋势,但变化值极小;对于波瓣混合器的相对质量,随着高宽比的增加,波瓣混合器的相对质量逐渐增大。
[Abstract]:Based on the Navier-Stokes equations, the forced hybrid exhaust system of turbofan engine is numerically simulated, and the flow area and flow area of the culvert in the trailing edge of the lobe are obtained. When the cross section area of the passage at the entrance position of the culvert is equal, the performance parameters and the structural parameters of the mixed exhaust system with different lobe height / width ratio are affected. An approximate model of lobe performance parameters varying with aspect ratio is established by using polynomial response surface models of different orders. In terms of fitting accuracy of polynomial response surface models, the second order and third order polynomial response surface models are compared to the second order polynomial response surface models. The fourth order polynomial response surface model can well reflect the variation of heat mixing efficiency, total pressure recovery coefficient, relative thrust of exhaust system and relative mass of wave lobe mixer with the ratio of wave lobe height to width. In the aspect of the effect of the ratio of wave lobe height to width on the performance of the hybrid exhaust system, at the exit section of the mixed exhaust system, the ratio of wave lobe height to width increases with the increase of the ratio of wave lobe height to width. The heat mixing efficiency shows the trend of "increase-decrease" in the variation law of "wave shape" as a whole. The total pressure recovery coefficient shows a complex trend of "slowly increasing-rapidly decreasing-increasing-rapidly decreasing". In the aspect of relative thrust of exhaust system, when the aspect ratio of aspect to width is greater than 3:00, the relative thrust presents a wave shape change trend, but the change value is very small. For the relative mass of the lobe mixer, the relative mass of the lobe mixer increases with the increase of the aspect ratio.
【作者单位】：重庆大学机械传动国家重点实验室;重庆大学汽车工程学院;中航工业沈阳发动机设计研究所;
【基金】：国家自然科学基金青年基金(51405045) 重庆市基础与前沿研究计划(cstc2013jcyj A00020) 中央高校基本科研业务费(106112013CDJZR13110005)
【分类号】：V235.13
【正文快照】： 1引言波瓣混合器由于其特殊的几何结构,能够在其流场中形成大尺度的流向涡结构,从而强化内、外涵流体间的混合,达到增加发动机推力,降低排气噪声,减小发动机耗油率的目的[1,2]。目前为止,关于波瓣混合器的研究主要包括三个方面:(I)波瓣混合器的混合机理;(II)波瓣形状对混合排

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