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1.
A redesign of a highly loaded fan stage by using high-turning bowed compressor stator was conducted. The original tandem stator was replaced by the highly loaded bowed stator which was applicable to highly subsonic flow conditions. 3D contouring technique and local modification of blade were applied to the design of the bowed blade in order to improve the aerodynamic performance and the matching of the rotor and stator blade rows. Performance curves at different rotating speeds and performances at different operating points for both the original fan stage and redesigned fan stage were obtained by numerical simulations. The results show that the highly loaded bowed stator can be used not only to improve the structure and the aerodynamic performances at various operating points of the compressor stage but also to provide high performances at off-design conditions. It is believed that the highly loaded bowed stator can advance the design of high-performance compressor. 相似文献
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Shaowen CHEN Fu CHEN Keli WANG Jun GU Zhongqi WANG 《Frontiers of Energy and Power Engineering in China》2008,2(3):306-312
The effects of a positively bowed blade on the aerodynamic performance of annular compressor cascades with different camber
angles were experimentally investigated. The distributions of the exit total pressure loss and secondary flow vectors of the
compressor cascades were analyzed. The static pressure was measured by tapping on the cascade surfaces, and the ink-trace
flow visualizations were conducted. The results show that the value of the optimum bowed angle and optimum bowed height decrease
because of the increased losses at the midspan with the increase of the camber angle. The C-shape static pressure distribution
along the radial direction exists on the suction surface of the straight cascade with larger camber angles. When bowed blade
is applied, the larger bowed angle and larger bowed height will further enhance the accumulation of the low-energy fluid at
the mid-span, thus causing the flow behavior to deteriorate. Under 60° camber angle, flow behavior near the end-wall region
of some bowed cascades even deteriorates instead of improving because the blockage of the separated flow near the mid-span
keeps the low-energy fluid near the endwalls from moving towards the mid-span region. As a result, a rapid augmentation of
the total loss can easily take place under a large bowed angle.
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Translated from Journal of Propulsion Technology, 2007, 28(2): 170–175 [译自: 推进技术] 相似文献
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采用数值模拟和试验相结合的方法对某十级高负荷高压压气机末级总温分布规律及产生机理进行了详细的分析和阐述。结果表明:压气机末级静叶出口总温在径向和周向的分布均呈现出较明显的非均匀分布,在径向上表现为叶根和叶尖区域总温高而叶中区域总温低的分布特征,在周向上表现为主流区总温低而尾迹区总温高的分布特征;径向总温分散度沿压气机末级静叶往下游发展过程中呈现逐渐降低的变化趋势,而周向总温分散度则呈现先增加后减小的变化趋势;压气机末级静叶入口总温径向不均匀分布及大弓形静叶设计产生的“C”型径向压力分布特征是导致压气机出口总温周向不均匀分布的根本原因。 相似文献
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An axial-type fan that operates at a relative total pressure of 671Pa and a static pressure of 560Pa with a flowrate of 416.6m3/min is developed using an optimization technique based on the gradient method. Prior to the optimization of the fan blade, a three-dimensional axial-type fan blade is designed based on the free-vortex method along the radial direction. Twelve design variables are applied to the optimization of the rotor blade, and one design variable is selected for optimizing a stator which is located behind the rotor to support a fan-driving motor. The total and static pressure are applied to the restriction condition with the operating flowrate on the design point, and the efficiency is chosen as the response variable to be maximized. Through these procedures, an initial axial-fan blade designed by the free vortex method is modified to increase the efficiency with a satisfactory operating condition. The optimized fan is tested and compared with the performance obtained with the same class fan to figure out the optimization effect. The test results show that the optimized fan not only satisfies the restriction conditions but also operates at the same efficiency even though the tip clearance of the optimized fan is greater than 30%. The experimental and numerical tests show that this optimization method can improve the efficiency and operating pressures on axial-type fans. 相似文献
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Hamzeh Eshraghi Masoud Boroomand Abolghasem M. Tousi Mohammad Toude Fallah Ali Mohammadi 《热科学学报(英文版)》2016,25(3):223-230
Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds.Considering the high aerodynamic load effects and structural concerns in the design process,it is possible to obtain higher pressure ratios compared to conventional compressors.However,it must be noted that imposing higher aerodynamic loads results in higher loss coefficients and deteriorates the overall performance.To avoid the loss increase,the boundary layer quality must be studied carefully over the blade suction surface.Employment of advanced shaped airfoils (like CDAs),slotted blades or other boundary layer control methods has helped the designers to use higher aerodynamic loads on compressor blades.Tandem cascade is a passive boundary layer control method,which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads.In fact,the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade's suction side.Also,in comparison to the single blade stators,tandem variable stators have more degrees of freedom,and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance.In the current study,a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage.Following,this design is numerically investigated using a CFD code and the stage characteristic map is reported.Also,the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed.To validate the CFD method,another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results. 相似文献
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研究了某轴流式压气机节流试验中的气动不稳定问题。运用非线性的相关积分方法对压气机机匣壁面沿程静压信号进行了分析。结果表明,压气机静叶通道机匣壁面给定点静压信号的相关积分值随着发动机工作状态的不同有规律的发生变化,反映了对应位置的流动分离状况;压气机沿程各级静叶通道机匣壁面静压的相关积分值可以反映不同工况时压气机各级叶尖的流动匹配情况;压气机第一级静子机匣壁面静压信号的相关积分值可以反映中低转速工况下放气带开关状态对转子端壁流态的影响。研究还表明,压气机静子机匣壁面沿程静压信号的相关积分分析是进行压气机气动稳定性监控诊断的一种有效手段。 相似文献
8.
A parametric method for the axial compressor 2D blade profiles is proposed in which the blade geometries are defined with
the parameters commonly used for blade definition, which ensures that the geometric significance is clear and an unreasonable
blade profile is not generated. Several illustrations are presented to show the fitting precision of the method. A novel response
surface model is proposed which regards the objective distribution function in the vicinity of a sample as normal school,
and then generates the response surface function in the whole design space by a linear combination of distribution functions
of all the samples. Based on this model, a numerical aerodynamic optimization platform for the axial compressor 2D blade profiles
is developed, by which aerodynamic optimization of two compressor blade profiles are presented.
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Translated from Acta Aeronautica et Astronautica Sinica, 2007, 28(4): 813–820 [译自: 航空学报] 相似文献
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目的是讨论弯扭叶片在大功率汽轮机低压缸末级的工程应用工程。弯扭叶片的通流设计采用全三元设计系统进行。通过对1m级叶片的气动分析,表明弯扭成型可以有效地调整等压线的分布形状,同时也应注意不同弯曲度所带来的负面效应,在设计中优化选取适当的弯曲度。 相似文献
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Jian JIANG Bo LIU Yangang WANG Xiangyi NAN 《Frontiers of Energy and Power Engineering in China》2008,2(3):320-325
Numerical simulation of three-dimensional turbulent flow in a multistage axial compressor blade row is conducted. A high resolution,
third-order ENN scheme is adopted to catch the shockwave and simulate the turbulent flow correctly, while an LU-SGS implicit
method is chosen to improve computation rate. A detailed and highly efficient numerical simulation system is thus constructed.
The investigation is focused on the grid connecting methods between the rotor and the stator and the corresponding treatment
of rotor-stator interactional surface. The final results of a three-stage axial compressor with inlet guide vanes conform
well to the experimental data.
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Translated from Chinese Journal of Applied Mechanics, 2007, 24(1): 21–25 [译自: 应用力学学报] 相似文献
14.
The S2 flow path design method of the transonic compressor is used to design the one stage fan in order to replace the original designed blade cascade which has two-stage transonic fan rotors. In the modification design, the camber line is parameterized by a quartic polynomial curve and the thickness distribution of the blade profile is controlled by the double-thrice polynomial Therefore, the inlet flow has been pre-compressed and the location and intensity of the shock wave at supersonic area have been controlled in order to let the new blade profiles have better aerodynamic performance. The computational results show that the new single stage fan rotor increases the efficiency by two percent at the design condition and the total pressure ratio is slightly higher than that of the original design. At the same time, it also meets the mass flow rate and the geometrical size requirements for the modification design. 相似文献
15.
Due to corner separation and other complex three-dimensional flows existing in the highly loaded stator, which influences the fan performance significantly, highly loaded stator blades of a transonic fan with a maximum camber angle of 57° were studied in this paper and sector cascade experiment was adopted. In order to get the stator aerodynamic parameters as realistic as possible and conduct the experiment without the existence of rotor, an adjustable guide vane was designed to simulate the velocity magnitude and direction of the stator inlet flow. Results show that the adjustable guide vane can simulate the rotor outlet velocity direction and magnitude in most span range. The deviation angle is positive and the maximum value is nearly 21° because the severe separation is at 27% span. Corner separation exists on both pressure side and suction side and the location of separation initiation is determined. Finally, the stator blades were redesigned with some suction slots on the suction side. Experiment results show that the suction slots change the flow field structure, increase the capability of flow turning, and decrease the flow loss. 相似文献
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提出了一种基于自然样条思想的弯叶片生成方法,推导了其积迭线的解析表达式.通过控制"弯度"参数可获得不同角度的弯叶片.将该弯叶片生成方法运用于某型冷却风扇,通过数值模拟研究了叶片各种弯曲形式对风扇气动性能的影响.结果表明:叶片前弯能有效抑制叶顶旋涡,降低叶顶区域的能量损失,扩大叶轮稳定工况范围;圆弧型弯叶片的风压略大于自然样条型弯叶片,但后者对降低叶顶区域能量损失更具明显优势. 相似文献
17.
The performance of fan stage in a small turbofan engines is significantly affected at high-altitude low Reynolds number. In order to examine the effect of low Reynolds number on the fan stage, 3D numerical simulation method was employed to analyse the performance variations and the underlying flow structure in the fan stage. For the sake of decreasing the influence of low Reynolds number, the different bowed stator airfoils were redesigned and the effect of the modified design was evaluated. 相似文献
18.
The effects of a positively bowed blade on the aerodynamic performance of annular compressor cascades with different camber angles were experimentally investigated. The distributions of the exit total pressure loss and secondary flow vectors of the compressor cascades were analyzed. The static pressure was measured by tapping on the cascade surfaces, and the ink-trace flow visualizations were conducted. The results show that the value of the optimum bowed angle and optimum bowed height decrease because of the increased losses at the mid-span with the increase of the camber angle. The C-shape static pressure distribution along the radial direction exists on the suction surface of the straight cascade with larger camber angles. When bowed blade is applied, the larger bowed angle and larger bowed height will further enhance the accumulation of the low-energy fluid at the mid-span, thus causing the flow behavior to deteriorate. Under 60° camber angle, flow behavior near the end-wall region of some bowed cascades even deteriorates instead of improving because the blockage of the separated flow near the mid-span keeps the low-energy fluid near the end-walls from moving towards the mid-span region. As a result, a rapid augmentation of the total loss can easily take place under a large bowed angle. 相似文献
19.
T. Korakianitis I.A. HamakhanM.A. Rezaienia A.P.S. WheelerE.J. Avital J.J.R. Williams 《Applied Energy》2012,89(1):215-227
The purpose of this paper is to present the advantages of the direct presCrIbed suRface Curvature distribution bLade dEsign (CIRCLE) method for the design of high-efficiency turbomachinery blades. These advantages are illustrated by redesigning several examples of axial turbomachinery blades of interest to energy conversion devices, and discussing in detail the aerodynamic performance and efficiency improvements of the redesigned blades over the original geometries. The two-dimensional (2D) method, originally proposed for turbine blades, has been extended for use with 2D and three-dimensional (3D) turbine, compressor and fan blades, and isolated airfoils. By specification, the method allows joining line segments between the leading edge (LE) and trailing edge (TE) circles or ellipses so that the streamwise distribution of surface curvature and slope of curvature are continuous everywhere from the LE stagnation point to the TE stagnation point. The form of the line segments to prevent the “wiggles” of higher order lines is presented. Also by specification, the CIRCLE method can be integrated with multi-objective heuristic or evolutionary-algorithm optimization methods. The efficacy of the method is examined by: redesigning two 2D turbine blades, one 2D compressor blade, and one 2D isolated airfoil; and by designing one 3D compressor blade row and one 3D turbine blade row. The aerodynamic performance improvements between the original and the sample redesigned blades are discussed in detail, resulting in higher-efficiency blades than the original geometries. Further extension of the method for centrifugal and mixed-flow impeller geometries is a coordinate transformation. It is concluded that the CIRCLE method is a new design environment enabling the original design (or redesign) of high-efficiency 2D and 3D turbomachine blades, with direct applications in a variety of energy conversion devices. 相似文献
20.
Chong-hyun Cho Soo-yong Cho Chaesil Kim 《Frontiers of Energy and Power Engineering in China》2009,3(4):414-422
An axial-type fan that operates at a relative total pressure of 671 Pa and a static pressure of 560 Pa with a flowrate of
416.6 m3/min is developed using an optimization technique based on the gradient method. Prior to the optimization of the fan blade,
a three-dimensional axial-type fan blade is designed based on the free-vortex method along the radial direction. Twelve design
variables are applied to the optimization of the rotor blade, and one design variable is selected for optimizing a stator
which is located behind the rotor to support a fandriving motor. The total and static pressure are applied to the restriction
condition with the operating flowrate on the design point, and the efficiency is chosen as the response variable to be maximized.
Through these procedures, an initial axial-fan blade designed by the free vortex method is modified to increase the efficiency
with a satisfactory operating condition. The optimized fan is tested and compared with the performance obtained with the same
class fan to figure out the optimization effect. The test results show that the optimized fan not only satisfies the restriction
conditions but also operates at the same efficiency even though the tip clearance of the optimized fan is greater than 30%.
The experimental and numerical tests show that this optimization method can improve the efficiency and operating pressures
on axial-type fans. 相似文献