导叶调节对双级离心压缩机性能影响的研究

发布时间：2018-03-14 03:24

本文选题：离心压缩机　切入点：双级　出处：《中国科学院研究生院(工程热物理研究所)》2016年硕士论文　论文类型：学位论文

【摘要】：在储能过程中,压缩子系统向储罐充气,压缩机排气压力持续升高,导致压缩机运行工况点持续变化。为了尽可能扩大离心压缩机的稳定工作范围同时获得较高的平均运行效率,改变进口导叶开度是常用的调节方法之一。本文以每级前均带有可调导叶的带级间冷却的双级离心压缩机为研究对象,通过性能预测和数值模拟方法,分析离心压缩机的导叶调节规律及其内部流动变化,主要研究内容如下：1.对离心压缩机可调导叶变工况调节进行性能预测研究。选取压缩机级内11种经验损失模型,通过Matlab建立性能预测程序,结果表明性能预测能够准确计算离心压缩机设计工况性能,偏离设计工况程度越大误差越大。充分考虑级内损失的分布规律,通过流量系数对4种主要损失进行修正,压比、效率最大误差控制在5%以内,效率最高点的预测值与模拟值基本吻合。2.利用预测模型计算双级离心压缩机导叶联合调节性能。与数值模拟相比,压比在近堵塞时误差逐渐增大,最大在6%左右；效率曲线与模拟曲线在近失速和堵塞时误差都有所增大,堵塞处更明显,最大在8.3%左右,效率最高点的预测值与模拟值基本吻合。3.分别对一、二级离心压缩机导叶调节进行数值模拟,分析调节规律产生机理。结果表明,小流量时叶轮进口攻角大,较大正开度改善了叶尖尾部吸力面的流动情况,降低压缩机在较小流量时失速的可能,导叶调节扩大了离心压缩机稳定运行工况；开度越大,叶轮内速度梯度越大,马赫数分布更加不均匀,级内损失增加,导叶调节时效率有所下降。4.利用多孔介质模拟级间冷却器,对双级离心压缩机导叶联合调节进行数值模拟。当第一、二级导叶都为负开度时压比增大,其余组合压比降低,任意导叶开度组合效率性能较基准工况降低。与无调节和单级导叶调节相比,双级联调大幅扩大了双级离心压缩机的稳定运行范围。双级联调效率高,绝大部分工况在80%以上。5.导叶调节时,在叶轮进口负开度时叶尖吸力面处的高速流体范围增大,正开度时随着开度增大,叶尖吸力面处的高速流体逐渐消失,并在叶尖压力面处出现；叶轮尾部吸力面靠近叶根处存在低速低能流体区域,随着开度增大尾迹区缩小。
[Abstract]:In the process of energy storage, the compression subsystem inflates to the tank, and the compressor exhaust pressure increases continuously. In order to enlarge the stable working range of centrifugal compressor and obtain higher average operating efficiency, Changing the opening of the inlet guide vane is one of the commonly used regulating methods. In this paper, the two-stage centrifugal compressor with adjustable guide vane before each stage is taken as the research object, and the performance prediction and numerical simulation method are used. The regulation law of guide vane and its internal flow change of centrifugal compressor are analyzed. The main research contents are as follows: 1. The performance prediction of adjustable guide vane regulation of centrifugal compressor is carried out. 11 kinds of empirical loss models in compressor stage are selected. The performance prediction program is established by Matlab. The results show that the performance prediction can accurately calculate the design performance of centrifugal compressor, and the greater the deviation from the design condition, the greater the error. The four main losses are corrected by flow coefficient. The maximum error of pressure ratio and efficiency is controlled within 5%. The predicted value of the highest point of efficiency is basically in agreement with the simulated value. 2. The combined governing performance of the guide vane of the two-stage centrifugal compressor is calculated by using the prediction model. Compared with the numerical simulation, the error of the pressure ratio in the near clogging increases gradually, the maximum is about 6%; The error between the efficiency curve and the simulation curve increases at near stall and clogging, and the clogging is more obvious, the maximum is about 8.3%, and the predicted value of efficiency highest point is basically consistent with the simulated value. Numerical simulation of guide vane regulation of two-stage centrifugal compressor is carried out and the mechanism of regulation law is analyzed. The results show that the impeller inlet angle of attack is large and the larger positive opening improves the flow situation of the suction surface at the tip tail of the blade when the flow rate is small. Reducing the possibility of compressor stall at a lower flow rate, the guide vane regulation expands the stable operating condition of the centrifugal compressor; the greater the opening degree, the greater the velocity gradient in the impeller, the more uneven the Mach number distribution, and the greater the loss in the stage. The efficiency of the guide vane is decreased. 4. By using porous media to simulate the interstage cooler, the combined regulation of the guide vane of the two-stage centrifugal compressor is numerically simulated. When the second stage guide vane is negative opening, the pressure ratio increases, while the other combined pressure ratio decreases. The combined efficiency performance of arbitrary guide vane opening is lower than that of the reference working condition. Compared with the non-adjustment and single-stage guide vane regulation, the double-cascade adjustment greatly expands the stable operation range of the two-stage centrifugal compressor. The double-cascade adjustment efficiency is high. Most of the working conditions are above 80% .5.When the guide vane adjusts, the range of high speed fluid at the suction surface of the tip increases when the inlet of the impeller is negative, and the high speed fluid at the suction surface of the tip gradually disappears with the increase of the opening. At the tip pressure surface, there is a low-velocity low-energy fluid region near the impeller tail suction surface near the blade root, and the wake area shrinks with the increase of opening.
【学位授予单位】：中国科学院研究生院(工程热物理研究所)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH452

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