轴流压气机叶尖间隙影响失速的机理及周向单槽机匣处理扩稳研究

发布时间：2018-01-12 04:05

本文关键词：轴流压气机叶尖间隙影响失速的机理及周向单槽机匣处理扩稳研究　出处：《西北工业大学》2015年博士论文　论文类型：学位论文

【摘要】：结合本课题组国家自然科学基金项目的开展,以西北工业大学孤立转子为研究对象,进行亚声速压气机失速实验研究。在此基础上利用数值模拟方法,对压气机失速机理、叶尖间隙变化对失速的影响以及周向单槽耦机匣处理扩稳研究。就上述问题,本文还对跨声速压气机rotor37进行研究,探讨亚声速和跨声速压气机在上述问题的异同。对亚声速压气机进行了失速实验研究,亚声速压气机实验测量结果表明,叶尖流场具有明显的非定常性。对叶片通过频率进行研究,发现效率峰值工况下叶片通过频率压力脉动幅度最大;而在近失速工况下,通过频率压力脉动幅值急剧下降;失速后,通过频率压力脉动幅度再次被增大。这一特点对于失速监测具有重要意义,可以设置叶片通过频率压力脉动幅度阈值。如果叶片通过频率压力脉动幅度突然小于阈值,意味着压气机进入失速边界。监测通过频率压力脉动幅值,可以有效地监控压气机工作状况,为失速的主动控制提前预警,具有一定的工程应用价值。通过非定常数值仿真计算,发现所研究亚声速压气机,在由近失速到失速过程中,存在明显的前溢后返现象。结合流场分析,认为“前溢后返”是叶尖间隙泄漏流与来流轴向动量相互作用的结果。为了便于定量研究叶尖间隙泄漏流与来流轴向动量的相互作用,提出用单位面积的叶尖间隙泄漏流动量与单位面积的来流动量比(Ba)作为叶尖间隙泄漏流与来流相交面的表征。发现所研究的压气机当Ba小于0.5时,压气机处于稳定工作区域;当Ba大于0.5时,压气机进入非稳定工况。本文还对跨声速转子rotor 37进行数值仿真,通过对流场分析,认为泄漏流与主流轴向动量的相互作用是引发跨声速压气机失速的根本原因。研究跨声速压气机叶尖间隙泄漏流与来流轴向动量比对压气机工作的影响,发现近失速工况下Ba值小于0.5。叶尖间隙变化可以诱导不同的失速机理,对压气机稳定工作范围有重要影响。无论是亚声速压气机还是跨声速压气机,随着叶尖间隙的增大,叶尖间隙泄漏流与来流的交界面不断前移,当叶尖间隙足够大时,在近失速工况下就表现出从前缘的溢出。叶尖间隙变化对Ba有影响。随着叶尖间隙的减小,Ba增加的趋势变缓。压气机稳定运行下,其Ba值不超过0.5;在压气机失速机理不改变的前提下,存在Ba值越小压气机稳定性越好的趋势。但是叶尖间隙减小到一定程度,失速机理会发生变化,致使Ba尚不能准确描述最佳间隙。周向单槽降低了局部位置叶片压力面、吸力面之间的压差,但在其下游方向,叶片压力面、吸力面之间的压差又一次增大,这种压差变化的现象对周向单槽的扩稳效果产生影响。叶尖间隙与周向单槽耦合研究发现,在小间隙下,无论周向单槽位于叶片前缘还是中间,稳定裕度都得到大幅改善,可以实现效率、压比不降低的同时,大幅提高压气机稳定裕度的目标;而在大间隙下,压气机的效率、压比、稳定裕度均有恶化。从机理角度,这是由于小叶尖间隙可抑制周向单槽机匣处理后叶片表面压差的变化现象。在上述研究的基础上,进一步探索叶尖小间隙下单槽槽深对压气机性能的影响,发现槽深过大会引起槽内涡流产生多余的能量损失。有效控制槽深既起到径向抽吸的作用,又要尽量避免多余的能量损失,是提高机匣处理效率的重要途径。
[Abstract]:According to the research group of National Natural Science Fund project carried out by Northwestern Polytechnical University rotor as the research object, for subsonic compressor stall experiment. Based on the numerical simulation method of compressor stall mechanism, variation of tip clearance effects on the stall and single circumferential groove casing treatment is the steady expansion research. In this paper, also studied the transonic compressor rotor37, to discuss the similarities and differences of the subsonic and transonic compressor in the above problems. The subsonic compressor was studied subsonic compressor stall, the experimental measurement results show that the tip flow field is unsteady obviously. The blade was studied by the blade frequency, peak efficiency under the condition of the frequency of pressure pulsation amplitude; while in the near stall condition, the frequency of the pressure fluctuation amplitude decreased sharply after the stall, the frequency; The rate of amplitude of pressure fluctuation was again increased. This feature is of great significance for the stall monitoring, you can set the blade passing frequency pressure fluctuation amplitude threshold. If the blade passing frequency sudden pressure pulsation amplitude is less than the threshold, means that the compressor enters the stall boundary. Through monitoring the frequency of pressure pulsation amplitude, can effectively monitor the working condition of the compressor, the initiative in advance stall warning control, has a certain value in engineering. By unsteady numerical simulation, it was found that the subsonic compressor, to stall process from near stall, there was before the spill phenomenon. After combining with flow field analysis, that "before the spill is to return" flow and axial momentum interaction leakage Ye Jian gap results. In order to facilitate the interaction of quantitative research Ye Jian leakage flow and flow axial momentum, the unit area of Ye Jian Flow and unit area leakage gap to flow momentum ratio (Ba) as the tip leakage flow and flow intersection surface characterization. The study found that the compressor when Ba is less than 0.5, the compressor in a stable working area; when Ba is greater than 0.5, the compressor enters the unsteady condition. This paper also on transonic rotor rotor 37 numerical simulation based on flow field analysis, that leakage interaction and main flow of axial momentum is the fundamental cause of transonic compressor stall. The influence of transonic compressor tip clearance leakage flow and flow ratio on the axial momentum compressor work, found near stall condition Ba value is less than 0.5. of tip clearance changes can stall different mechanisms of induction, has an important influence on the stable working range of the compressor. Both subsonic compressor or transonic compressor, with the increase of the tip clearance, the tip clearance leakage Flow and flow interface continuously forward, when the tip clearance is large enough, at near stall condition showed from the leading edge of the overflow. The tip clearance changes affect Ba. With the decrease of the tip clearance, Ba increased slowly. The compressor stable operation, the Ba value of not more than 0.5; in do not change the premise of the stall mechanism, there is Ba smaller compressor stability good trend. But the tip clearance is reduced to a certain extent, stall mechanism will change, resulting in Ba cannot accurately describe the optimum clearance. Single circumferential groove reduces the local position of the pressure surface of the blade suction surface, the pressure difference between, but in in the downstream direction, the pressure surface of the blade suction surface, the pressure difference between again increased, this will affect the change of pressure difference phenomenon of single circumferential groove stability enhancement effect. The tip clearance and circumferential groove coupling study found that in small gaps, regardless of the week To the single slot in the leading edge of the blade or in the middle, the stability margin has been greatly improved, can realize the efficiency, pressure ratio does not decrease at the same time, a substantial increase in the compressor stability margin target; and in the large gap, compressor pressure ratio, efficiency, stability margin has deteriorated. From the theoretical point of view, this is because the phenomenon of change of small tip clearance can inhibit the single circumferential groove casing treatment after the blade surface pressure difference. On the basis of the above research, to further explore the tip gap single groove deep influence on the compressor performance, found that the groove depth will cause the tank eddy current loss of energy excess. Effective control of groove depth is the radial suction effect, but also to avoid unnecessary loss of energy, is an important way to improve the efficiency of casing treatment.

【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH453

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