Study of Mach Number Effect for 3D Co-Flow Jet Wings at Cruise Conditions
Study of Mach Number Effect for 3D Co-Flow Jet Wings at Cruise Conditions
复制标题
巡航工况下3D同流喷气机翼马赫数效应研究
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Gecheng Zha
中科院分区：
文献类型：
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作者：
Yang Wang;Gecheng Zha
本文数值研究了自由飞行马赫数为0.15、0.30、0.35、0.40、0.46和0.50时，马赫数对三维同向射流机翼巡航性能的影响。以CFJ-NACA-6421翼型为基础，研究了展弦比为5、10和20的非后掠机翼。数值模拟采用经过严格验证的内部FASIP CFD代码，该代码采用Spalart-Allmaras（S-A）湍流模型的3D RANS求解器，无粘通量采用三阶韦诺格式，粘性项采用二阶中心差分。与以前的二维研究类似，由于压缩性效应，三维升力系数随马赫数增加。然而，由于诱导阻力和CFJ功率系数的增加，从2D到3D，总体气动效率和生产率大幅下降。随着纵横比的减小，惩罚进一步增加。在相同展弦比下，与具有NACA-6421翼型的基线三维机翼相比，巡航升力系数在AR为5时平均增加约30%，在AR为20时平均增加约60%。当AR为20时，纯气动升阻比CL/CD也增加了约30%。考虑CFJ泵功率消耗后，等效气动效率（CL/CD）c与基准机翼相当。由于升力系数的增加，生产效率（C L/CD）c增加了约30%。当AR为5时，即使保持高巡航升力系数，也不会获得效率优势。研究表明，CFJ机翼采用厚翼型有利于亚音速巡航，尤其是大展弦比机翼，巡航马赫数可达0.50。
This paper numerically studies the Mach number effect on cruise performance of 3D Co-Flow Jet (CFJ) wings at freestream Mach number of 0.15, 0.30, 0.35, 0.40, 0.46 and 0.50. The non-swept wing with three aspect ratios (AR) of 5, 10 and 20 based on CFJ-NACA-6421 airfoil are investigated. The numerical simulations employ the intensively validated in house FASIP CFD code, which utilizes a 3D RANS solver with Spalart-Allmaras (S-A) turbulence model, 3rd order WENO scheme for the inviscid fluxes, and 2nd order central differencing for the viscous terms. Similar to the previous 2D study, the 3D lift coefficient is increased with the Mach number due to compressibility effect. However, the overall aerodynamic efficiency and productivity are substantially dropped from 2D to 3D due to increased induced drag and the CFJ power coefficient. The penalty is further increased with the decreased aspect ratio. Compared with the baseline 3D wing with NACA-6421 airfoil at the same aspect ratio, the cruise lift coefficient is increased on the average by about 30% for AR of 5 and 60% for AR of 20. For the AR of 20, the pure aerodynamic lift to drag ratio CL/CD is also increased by about 30%. Considering the CFJ pumping power consumption, the equivalent aerodynamic efficiency (CL/CD)c is about the same as the baseline wing. The productivity efficiency (C L/CD)c are increased by about 30% due to the increased lift coefficient. For AR of 5, no efficiency advantage is obtained even though the high cruise lift coefficient remains. The study indicates that the CFJ wing with a thick airfoil is advantageous for cruise at subsonic speed up to Mach number of 0.50, in particular for high aspect ratio wing.