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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。
Based on the Navier-Stokes equations, the forced mixed exhaust system of the turbofan engine lobe was numerically simulated, and the cross-sectional area of the inner and outer culverts at the trailing edge of the lobe was the same as that at the inlet of the outer and outer culverts Effect of Lobe Aspect Ratio on Performance Parameters and Structure Parameters of Lobe Hybrid Exhaust System. Based on this, an approximate model of the variation of the performance parameters of the lobe with the aspect ratio was established by using the polynomial response surface model with different orders. Compared with the second-order and third-order polynomial response surface models, the fourth-order polynomial response surface model can better reflect the thermal mixing efficiency, the total pressure recovery coefficient, the exhaust system relative thrust, wave The change rule of the relative mass of the petal mixer with the lobe aspect ratio, the fitting result and the numerical simulation result are very similar. In the aspect of the effect of lobe aspect ratio on the performance of the hybrid exhaust system, at the exit section of the hybrid exhaust system, as the lobe aspect ratio increases, the overall efficiency of the thermal mixing in the “wavy” variation The total pressure recovery coefficient shows a complex trend of “slow increase-rapid decrease-increase-rapid decrease”; in the relative thrust of the exhaust system, when the width When the ratio is greater than 3, the relative mass of the lobe mixer gradually increases with the increase of aspect ratio, although the relative thrust shows a wavy trend.