【作者】 初雷哲；

【导师】 徐建中； 杜建一；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 工程热物理， 2008， 博士

【摘要】 近年来，随着全球范围内的能源与动力需求结构特别是电力系统的放松控制以及环境保护等要求的变化，微型燃气轮机近年来得到了电力、动力等有关部门的高度重视。作为微型燃气轮机的核心部件之一的高转速、高压比离心压气机的设计在微型燃气轮机的设计体系中具有举足轻重的地位。国内外学者对高转速、高压比的离心压气机已经进行了大量的实验和数值研究，并取得了一些进展。我国从八十年代起开始了对高压比离心压气机的型号研究，但是对其中详细的流动机理研究较少，这也影响了我国对高转速、高压比离心压气机的自主研发能力。在这一背景下，本文对高压比的离心压气机中的流动特性进行了详细的研究，主要内容如下：1．对高转速、高压比离心压气机内部流动进行了详细的数值研究，分析了高转速、高压比离心压气机中影响性能提高的因素，并对叶轮流道中间隙泄漏流动的发展以及叶轮尾迹损失的发展进行了详细分析。2．研究了叶轮中不同形状叶片前缘对离心压气机性能和流场的影响，分别研究了无叶顶间隙和带有叶顶间隙的情况。对十轮通道中叶片前缘顶部激波引起的流动分离对流道中流场的影响进行了详细分析，指出了在高转速、高压比离心压气机中叶片前缘形状对压气机性能产生较大影响的原因。分别研究了大小叶片前缘形状对流场作用的不同效果，并对带有叶顶间隙情况下，叶片前缘形状对前缘间隙泄漏损失的影响进行了比较。还进一步研究了不同叶顶间隙的影响，分析了叶顶间隙存在对流场产生的影响以及不同叶顶间隙对间隙涡的发展、叶顶激波引起的流动分离等现象的影响。3．在以上工作的基础上，结合863微燃机项目，针对设计的离心压气机的叶轮与扩压器进行数值计算，并与实验结果进行对比，基本达到设计要求。对离心压气机和向心涡轮进行性能匹配，并与整机的实验结果对比，能较好的预测微型燃气轮机的共同工作曲线。4．对离心压气机中叶轮和有叶扩压器之间的相互作用进行了非定常的数值研究，分别研究了不同无叶扩压段以及扩压器叶片不同倾角对离心压气机性能和流场的影响。分析了无叶扩压段变化对离心压气机性能的影响方式，以及其对叶轮和扩压器相互作用强度的影响，探讨了合理选择无叶扩压段对于离心压气机性能的优化的可能。分析了扩压器叶片倾角变化对扩压器叶片压力面流动的影响，同时分析了倾角变化对叶轮和扩压器间相互干涉造成的流场波动的影响。本论文的研究结果表明，高转速、高压比离心压气机内部存在复杂的流动，通过对其流动机理的探讨与研究，可以为进一步开展离心压气机内部流动的研究提供有效的理论依据；为提高离心压气机设计水平提供技术积累。更多还原

【Abstract】 In the recent few years, microturbine has been paid more and more attentions in the field of electric power. The design of centrifugal compressor with high rotation speed and high pressure ratio, which is one of the cores of the microturbine, plays an important part in the microturbine design. A lot of manpower and financing have been spent on studying the centrifugal compressor, since the centrifugal compressor was invented. In our country, the study on centrifugal compressor with high rotation speed and high pressure ratio started from the 1980s, and the study was mainly about some specific types of centrifugal compressor. More work is necessary to improve the ability of design centrifugal compressor with high rotation speed and high pressure ratio. The detailed flow analysis in a centrifugal with high rotation speed and high pressure ratio is undertaken in this paper. The main content in this paper is listed as follows:1. The analysis of the flow in the centrifugal compressor with high rotation speed and high pressure ratio is performed to investigate the factors that affect the performance improvement, and to analyze the development of the tip leakage in the impeller and the development of the wake in the impeller.2. Investigations are performed to study the effect of the blade leading edge on the performance and flow of the compressor. The cases with tip gap and without tip gap are investigated separately. The interaction between the shock wave and the boundary layer at the leading edge of the blade is analyzed to discuss the reason of the obvious effect of blade leading edge on the stage performance. The leading edge geometry of main blade and splitter are also separately studied. As the tip leakage in the impeller has great influence on the flow and performance, different sizes of the tip gap are applied to the impeller to study the effect of tip gap on the development of tip leakage vortex and flow separation caused by shock wave near leading edge.3. Based on the former work and the 863 project on microturbine, the designed centrifugal compressor with high rotation speed and high pressure ratio was simulated, and the performance of the experiment meets the design requirement. The matching between the compressor and turbine is also undertaken, and is compared to the result of the microturbine operation, which shows good agreement between prediction and experiment.4. Unsteady simulations are performed to study the interaction between the impeller and vaned diffuser. Different radial gaps and different vane incline angles are separately analyzed. The effect of radial gap on the performance of different parts in the centrifugal compressor is investigated. The reasonable radial gap is discussed to optimum the performance of the compressor. For the analysis of the different vane incline angle, the focus is the investigation on the flow field of the pressure side in the vaned diffuser. The effect of the incline angle on the fluctuation of the flow field in both the impeller and vaned diffuser is also studied.The work of this paper shows that the flow in centrifugal compressor with high pressure ratio is very complex, and to investigate the flow characteristics will supply efficient suggestions for the improvement of the centrifugal compressor.更多还原