为有效抑制高负荷压气机内的流动分离，并提高其增压能力，本文研究了一种基于康达喷气的新型主动流动控制方法。叶片采用了扩压因子为0.66的Zierke&Deutsch双圆弧叶型。首先，对康达喷气缝进行参数化建模，研究中保证叶型型线光滑且连续；然后，基于对原叶型流场的分析，提出了前缝、后缝和双缝三种初始康达喷气叶型结构，针对该三种康达喷气叶型的几何参数，采用耦合遗传算法的神经网络模型进行了优化，并结合高精度数值模拟对比分析了三种康达喷气结构对叶型气动性能的影响效果及作用机理。结果表明，基于康达喷气的流动控制方法能够有效改善高负荷叶型的气动性能，且双缝康达喷气叶型的气动性能最佳。同时，相比于原始叶型，当双缝结构前缝和后缝的喷气-主流流量比分别为1.5%和0.5%时，能使叶型总压损失系数降低52.5%且使静压升系数提高25.7%。最后，基于流动控制效果最好的双缝康达喷气叶型，分析了叶型几何设计参数和喷气流量对气动性能的改善机制。结果表明，康达喷气叶型的几何设计参数主要影响叶型厚度和喷气缝的起始位置，从而增加流动速度并抑制流动分离。不同来流冲角条件下，采用不同的前、后缝喷气流量可使康达喷气的流动控制效果最佳。这为基于康达喷气的主动控制奠定了理论基础。
ZHANG Jian
,
DU Juan
,
ZHANG Min
,
CHEN Ze
,
ZHANG Hongwu
,
NIE Chaoqun
. Aerodynamic Performance Improvement of a Highly Loaded Compressor Airfoil with Coanda Jet Flap[J]. 热科学学报, 2022
, 31(1)
: 151
-162
.
DOI: 10.1007/s11630-022-1564-2
Coanda jet flap is an effective flow control technique, which offers pressurized high streamwise velocity to eliminate the boundary layer flow separation and increase the aerodynamic loading of compressor blades. Traditionally, there is only single-jet flap on the blade suction side. A novel Coanda double-jet flap configuration combining the front-jet slot near the blade leading edge and the rear-jet slot near the blade trailing edge is proposed and investigated in this paper. The reference highly loaded compressor profile is the Zierke & Deutsch double-circular-arc airfoil with the diffusion factor of 0.66. Firstly, three types of Coanda jet flap configurations including front-jet, rear-jet and the novel double-jet flaps are designed based on the 2D flow fields in the highly loaded compressor blade passage. The Back Propagation Neural Network (BPNN) combined with the genetic algorithm (GA) is adopted to obtain the optimal geometry for each type of Coanda jet flap configuration. Numerical simulations are then performed to understand the effects of the three optimal Coanda jet flaps on the compressor airfoil performance. Results indicate all the three types of Coanda jet flaps effectively improve the aerodynamic performance of the highly loaded airfoil, and the Coanda double-jet flap behaves best in controlling the boundary layer flow separation. At the inlet flow condition with incidence angle of 5°, the total pressure loss coefficient is reduced by 52.5% and the static pressure rise coefficient is increased by 25.7% with Coanda double-jet flap when the normalized jet mass flow ratio of the front jet and the rear jet is equal to 1.5% and 0.5%, respectively. The impacts of geometric parameters and jet mass flow ratios on the airfoil aerodynamic performance are further analyzed. It is observed that the geometric design parameters of Coanda double-jet flap determine airfoil thickness and jet slot position, which plays the key role in supressing flow separation on the airfoil suction side. Furthermore, there exists an optimal combination of front-jet and rear-jet mass flow ratios to achieve the minimum flow loss at each incidence angle of incoming flow. These results indicate that Coanda double-jet flap combining the adjust of jet mass flow rate varying with the incidence angle of incoming flow would be a promising adaptive flow control technique.
[1] Deutsch S., Zierke W.C., The measurement of boundary layers on a compressor blade in cascade: part 1-a unique experiment facility. Journal of Turbomachinery, 1987, 109(4): 520–526.
[2] Lee N.K.W., Greitzer E.M., Effects of endwall suction and blowing on compressor stability enhancement. Journal of Turbomachinery, 1990, 112(5): 133–144.
[3] Zhou Y., Liu H.X., Zou Z.P., Ye J., Boundary layer separation control on a highly-loaded, low-solidity compressor cascade. Journal of Thermal Science, 2010, 19(2): 97–104.
[4] Zheng X., Li Z., Blade-end treatment to improve the performance of axial compressors: an overview. Progress in Aerospace Sciences, 2017, 88: 1–14.
[5] Li Y.H., Wu Y., Zhou M., Su C.B., Zhang X.W., Zhu J.Q., Control of the corner separation in a compressor cascade by steady and unsteady plasma aerodynamic actuation. Experiments in Fluids, 2010, 48(6): 1015–1023.
[6] Dal M.A., Castelli M., Benini E., A retrospective of high-lift device technology. Engineering and Technology, 2012, 71: 1979–1984.
[7] Edward L., Clark J., An experimental study of jet-flap compressor blades. Journal of the Aerospace Sciences, 1959, 26(11): 698–702.
[8] Landsberg T.J., Krasnoff E., An experimental study of rectilinear jet-flap cascades. Journal of Basic Engineering, 1972, 94(1): 97–104.
[9] Inventions R., Aviation P.I., Constantin C, Gheorghiu, Ed. Albatros, Bucharest, 1979.
[10] Hill H.E., Ng W.F., Vlachos P.P., Guillot S.A., Bailie S.T., 2D parametric study using CFD of a circulation control inlet guide vane. 5th Joint ASME/JSME Fluids Engineering Conference, San Diego, California USA, 2007, FEDSM2007-372294. DOI: 10.1115/fedsm2007-37294.
[11] Fischer S., Saathoff H., Radespiel R., Two-dimensional RANS simulations of the flow through a compressor cascade with jet flaps. Aerospace Science and Technology, 2008, 12(8): 618–626.
[12] Vorreiter A., Fischer S., Radespiel R., Seume J.R., Numerical investigations of the efficiency of circulation control in a compressor stator. Journal of Turbomachinery, 2012, 134(2): 021012.
[13] Fischer S., Müller L., Kožulović D., Three-dimensional flow through a compressor cascade with circulation control. Proceedings of ASME Turbo Expo 2012, Copenhagen, Denmark, 2012, GT2012-68593. DOI: 10.1115/gt2012-68593.
[14] Guendogdu Y., Vorreiter A., Seume J.R., Design of a low solidity flow-controlled stator with Coanda surface in a high-speed compressor. Proceedings of ASME Turbo Expo 2008: Power for Land, Sea and Air, Berlin, Germany, 2008, GT2008-51180. DOI: 10.1115/gt2008-51180.
[15] Schwerdt L., Siemann J., Seume J.R., Active flow control implemented in a multi-stage high-speed axial compressor. PAMM, 2016, 16(1): 645–646.
[16] Zierke W., Deutsch S., The Measurement of boundary layers on a compressor blade in cascade volume 1 experimental technique, analysis and results. NASA Technical Report, CR-185118, 1989.
[17] Li Z., Zheng X., Review of design optimization methods for turbomachinery aerodynamics. Progress in Aerospace Sciences, 2017, 93: 1–23.
