【作者】 王永生；

【导师】 聂超群； 林峰；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 动力机械及工程， 2014， 博士

【摘要】 叶轮机械作为国民经济的支柱产业,其运行效率决定了能耗的高低,稳定性直接影响着整个机组的安全。对于其中的高端产品离心压气机而言,目前各行业的需求朝着高压比、高效率及高稳定性的方向发展。例如：军方无人机等应用领域需要高压比离心压气机,过程工业需要高效率、高稳定性的多级离心压气机产品等等。从近年来离心压气机的市场份额来看,在制冷和天然气输送等领域,国外多级离心压气机产品一直占据垄断地位。加之国防领域对无人机的需求,很有必要加强离心压气机的设计研究。较为有效的途径为自主开发高适应性、高性能的离心压气机气动设计程序,开展不同产品研发工作,掌握不同流量系数类型、不同压比离心压气机的关键设计技术,最终服务于我国军用、民用离心压气机产品的开发。本文以自主研发离心压气机气动设计程序为主,采用不同流量系数离心压气机的数值模拟和试验数据对设计程序性能进行了验证；然后利用所开发的设计程序,针对各领域对离心压气机新的需求,研发多款不同流量系数的单级离心压气机；最后将单级离心压气机设计技术集中体现在一款1.5MW、总压比为12的单轴多级离心压气机上,从而积累掌握单、多级离心压气机关键设计技术。与此同时,开展了离心叶轮-扩压器之间的局部流动研究,探讨该区域流动状况与离心压气机扩稳的关联性。本文的核心内容主要分为以下几个部分：(1)自主研发离心压气机气动设计程序,包含设计模块和分析模块,采用不同流量系数离心压气机的试验和数值模拟数据整体验证设计程序的性能；(2)基于开发的气动设计程序,结合不同的实际工程应用背景,设计了涵盖低、中、高流量系数的单级离心压气机,其中包括：为某款多级离心压气机设计的一款以天然气为工作介质的离心压气机,用作于最后一级；为碟式太阳能空气涡轮发电系统设计的小流量、高压比单级离心压气机；为美国密歇根州立大学改进设计了一款高流量系数(0.2)离心压气机；为企业开发了一款用于电厂脱硫氧化和生物发酵的大流量、高压比离心压气机产品,并通过样机试验进行了性能验证；(3)研发了一款1.5MW、总压比为12、以空气为介质的单轴多级离心压气机,前后5级离心压气机采用“背靠背”结构布置,以相互抵消部分轴向力。由于涵盖不同流量系数类型的单级离心压气机,该多级离心压气机设计工作既可集中检验本文开发的气动设计程序性能,又可以积累和掌握多级离心压气机诸如级数分配、各级功率和压比分配、单根轴上性能指标限制值等关键设计技术；(4)开展了离心压气机叶轮-扩压器无叶扩压段流路扩稳的机理研究。提出了先缩后扩的叶轮-扩压器间轮盖型线,通过控制与利用叶轮-扩压器间轮盖区域的分流涡,以达到扩稳的目的。更多还原

【Abstract】 Turbomachinery has already become a mainstay in our national economy. Its performance affects power consumption and machine running safety directly. The demands on the centrifugal compressors with higher efficiency and total pressure ratio are increasing. For example, military UAV (Unmanned Aerial Vehicle) employs centrifugal compressors with high pressure ratio. Those centrifugal compressors with high efficiency and excellent stability are needed in process industry. Moreover, foreign multistage centrifugal compressor products applied in the air-conditioning and natural gas transportation fields take the main share of China market. Therefore, the effective solution is to develop aerodynamic design program for centrifugal compressors including different flow coefficient type. Through this process, key design technologies can be accumulated and served for the corresponding application areas.Aerodynamic design program for centrifugal compressors was developed based on empirical loss models and calibrated by three centrifugal compressors having experimental and numerical simulation data. Then, four single stage centrifugal compressors with different inlet flow coefficient were designed for specific projects by means of the self-developed design program. One of the four centrifugal compressors has been manufactured and will be tested by a coorperative company to confirm its performance.A low flow coefficient centrifugal compressor was developed as the last stage of a multistage compressor. The flow medium was natural gas. The design goal was to achieve higher efficiency. According to the requirements of a solar dish-brayton system, a centrifugal compressor stage with a minimum total pressure ratio of5, an adiabatic efficiency above75%and a surge margin more than12%needs to be designed. A single stage, which consists of impeller, radial vaned diffuser,90°crossover and two rows of axial stators, has been designed to satisfy the requirement of the solar dish-brayton system. To achieve the specific stage performance, an impeller with a6:1total pressure ratio and an adiabatic efficiency of90%was designed and its preliminary geometry came from an in-house one-dimensional program. Radial vaned diffuser was applied downstream of the impeller. Two rows of axial stators after90°crossover were added to guide the flow into axial direction. This centrifugal compressor belonged to medium flow coefficient type. A centrifugal compressor with high inlet flow coefficient of0.2, having a narrow operating range and unstable running situation even at design speed during the test, was investigated. To better reveal flow details in this centrifugal compressor, numerical simulations have been carried out and indicate that excessive impeller flow diffusion results in the poor performance of this centrifugal compressor. For the same inlet flow coefficient, six redesign cases coming from an in-house one-dimensional analysis program were proposed together with impeller trimming and equal flow area design method for corresponding vaneless diffuser. Finally, a suitable redesign case was selected and analyzed.Based on the accumulated design technology regarding different coefficient centrifugal compressors, a multistage centrifugal compressor with the total pressure ratio of12was designed, which would either verify the performance of developed design system or satisfy the need of a project. This multistage centrifugal compressor employed a single shaft, back-to-back structure layout. An intercooler was added between the fifth stage and the sixth stage. The numerical simulation indicated that the performances of this multistage centrifugal compressor were satisfactory. During the design process, related key design technologies were also accumulated.The flow situation between impeller exit and diffuser inlet was thought to be critical to the aerodynamic performance and stability of centrifugal compressors. To investigate the stall improvement mechanism of vaneless diffuser flow path control, a centrifugal compressor is simulated and compared with existing experimental data. According to characteristics of flow field and stall mechanism, a convergent-divergent type of impeller-diffuser casing was designed and analyzed. The result showed that the stable flow range of centrifugal compressor increased by2.8%, however, no obvious positive effects were found on the adiabatic efficiency, which was slightly lower than that of prototype.更多还原