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为解决使用CFD方法研究翼尖涡流场时存在的传统湍流模式难以准确计算翼尖涡的强旋流场的问题,本文使用添加旋转修正的SST-RC模式计算了光滑机翼的翼尖涡流场,并通过与实验结果进行对比,验证了该模式对于翼尖涡流场的有效性。然后使用该模式计算了翼梢小翼后的翼尖涡流场,发现翼梢小翼作为一种涡扩散器能够将原来强度集中的翼尖涡破碎分解成两个旋涡,这两个旋涡互相作用,加速了翼尖涡的粘性耗散。通过改变小翼的三个几何参数:根弦长Cr、倾斜角θ、外撇角,计算了不同外形翼梢小翼后的翼尖涡流场,同时引入一个翼尖涡的强度尺度S,考察S在尾缘下游的分布,发现添加小翼后S普遍下降了10%~20%。改变小翼根弦长对S的衰减影响不太明显,不同根弦长对应的S值相差2%~4%,Cr=0.7c时效果最佳;改变小翼倾斜角θ对S的影响在初始时差别较大,不同倾斜角对应的S相差约9%,在下游后期S差别较小,相差约3%,θ=20°时效果最佳;与倾斜角θ类似,改变小翼外撇角对S的影响在初始时差别较大,不同外撇角对应的S相差约10%,在下游后期S差别较小,相差约1%,=5°时效果最佳。
In order to solve the problem that it is difficult to accurately calculate the strong vortex flow field of the tip vortex with the traditional turbulence model when the CFD method is used to study the tip vortex field, the tip-vortex field of the smooth wing is calculated using the SST- , And compared with the experimental results to verify the effectiveness of the model for wing tip eddy current field. Then the vortex field of wingtip was calculated by using this model. It was found that the winglets, as a vortex diffuser, could disintegrate the original concentrated wingtip vortex into two vortices, and the two vortices interact with each other , Accelerated the viscous dissipation of wingtip vortex. By changing three geometric parameters of winglet, such as root chord length Cr, inclination angle θ, and external skimming angle, the wing tip vortex field with different shape winglets is calculated, and the strength scale S of a wing tip vortex is introduced S distribution in the downstream of the trailing edge, we found that after adding a small wing S generally declined by 10% to 20%. The effect of changing the root chord of small winglets on the attenuation of S is not obvious. The S values corresponding to different root chord differ by 2% ~ 4%, and the effect is best when Cr = 0.7c; The initial difference is larger, the difference between S corresponding to different tilt angles is about 9%, and the difference is small at the later stage, with a difference of about 3%. When θ = 20 °, the effect is the best. Similar to the tilt angle θ, The influence of angle on S is larger at the beginning. The difference of S corresponding to different write-off angles is about 10%, and the difference is small at the later stage. The difference is about 1%, and the effect is best at = 5 °.