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The present work is about the stall margin enhancement ability of a kind of stall precursor-suppressed (SPS) casing treatment when fan/compressor suffers from a radial total pres-sure inlet distortion. Experimental researches are conducted on a low-speed compressor with and without SPS casing treatment under radial distorted inlet flow of different levels as well as uniform inlet flow. The distorted flow fields of different levels are generated by annular distortion flow gen-erators of different heights. The characteristic curves under these conditions are measured and ana-lyzed. The results show that the radial inlet distortion could cause a stall margin loss from 2% to 30% under different distorted levels. The SPS casing treatment could remedy this stall margin loss under small distortion level and only partly make up the stall margin loss caused by distortion in large level without leading to perceptible additional efficiency loss and obvious change of charac-teristic curves. The pre-stall behavior of the compressor is investigated to reveal the mechanism of this stall margin improvement ability of the SPS casing treatment. The results do show that this casing treatment delays the occurrence of rotating stall by weakening the pressure perturbations and suppressing the nonlinear amplification of the stall precursor waves in the compression system. 相似文献
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《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(10):2263-2275
Optomechanical systems are very complex requiring a high degree of accuracy. The carrier structure of an optical system is required to maintain the position of the optical components with respect to each other within the design tolerances. The most common loads on optical systems are self-weight, due to gravity orientations, and temperature ranges, due to exposure to rapidly changing temperatures from very cold to very hot and during launch. The fixing should ensure mechanical stability and thus accurate positioning in various gravity orientations.In order to ensure reliability during a space flight mission, the optomechanical engineer must understand the requirements of the space flight environment as well as the physics of failure of the optical components themselves; this can minimize the risks of on-orbit failure.This paper focuses on the optomechanical optimal design lens mounting using glue pads bonding. The main idea of this research study is to obtain an optimal choice of the position of the glue to fix the lenses on the barrel in such a way that we obtain a configuration of the optical assembly performance with less stress.In this paper, an investigation was performed using several methods including (thermo-elastic analysis, the margin of safety and lens distortion analysis). The results show that the position with six contacts glue pads is the best configuration compared to other configurations. This solution can be very helpful for decision-makers and optical engineers during the development phases of space optomechanical systems. 相似文献
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45°周向压力畸变对轴流压气机影响的实验研究和机理分析 总被引:1,自引:0,他引:1
设计了一种45°周向压力畸变模拟发生器, 并在某高速轴流压气机实验台进行了实验研究.在中等转速下, 详细研究了45°周向压力畸变对该轴流压气机级的转子的性能影响, 以及整个轴流压气机级(转子进口、转子出口和静子出口)的压力周向分布.研究结果表明, 在中等转速下, 畸变区的范围在转子出口转移和扩大并不明显, 但是在静子出口扩大了近100%;在转子出口畸变强度明显增强, 而在静子出口强度衰减;与均匀进气的情况相比, 压气机转子压比提高了1.8%, 近失速点换算质量流量减小了2.5%. 相似文献
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通过有限元数值模拟和工艺试验相结合的方法对板料厚度为0.96mm的TA2M钛板的扩孔成形过程及结果进行了研究.运用PAM-STAMP有限元数值模拟分析软件对成型过程及卸载回弹结果进行预测.发现TA2M在成型卸载回弹后存在明显的形状畸变现象:孔口非圆化,孔口边缘厚度非均匀减薄以及凸缘非圆化.模拟预测结果与工艺试验结果比较吻合. 相似文献
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