【作者】 杨凌；

【导师】 钟兢军；

【作者基本信息】 大连海事大学 ， 轮机工程， 2011， 博士

【摘要】 旋转冲压压缩转子为一种基于激波压缩技术的新型压缩系统,融超声速进气道及传统轴流、离心压气机设计方法于一体,具有单级压比高、体积小、重量轻等优点。近十几年来,该压缩系统受到国内外能源、电力、动力、交通部门及研究者们的高度关注。特别是当今的电力工业正在向依靠大型发电和小型分布式发电广泛相结合的“分散式电力系统”转变,而分布式发电的技术核心是分布式电源,在众多分布式电源装置中,低污染小型燃气轮机是目前最具有商业竞争力的分布式发电设备,对作为低污染小型燃气轮机中新型高效压缩系统——基于激波压缩技术的旋转冲压压缩转子的研究是其重点之。对这种新型高效的压缩系统开展深入的研究具有重要的理论意义和实际应用价值。近几年,.国内已有一些科研院所开展了相关研究,但仍有许多工作需要深入开展。本文首先通过理论分析来找寻影响旋转冲压压缩转子性能的主要因素,然后考虑各种影响因素,借助CAD软件和FLUENT商用软件对两种结构的旋转冲压压缩转子(Ram-rotor压缩转子和Scrampressor压缩转子)进行三维设计、数值模拟及分析,最后对综合性能较好的方案进行性能仿真。通过课题研究,获得较为全面系统的旋转冲压压缩转子的研究数据,为旋转冲压压缩转子下一步开展试验研究和迈向实际应用奠定坚实基础。对于Ram-rotor压缩转子,隔板截面形状为“正梯形”的Ram-rotor压缩转子综合性能要好于“倒梯形”；喉部长高比过大或过小均会导致等熵绝热效率及总压比的下降；压缩角及扩压角的变化对压缩转子性能影响不明显；大隔板安装角可以使转子出口平均气流角减小,但是会降低总压恢复系数和总压比,过大或过小的隔板安装角都会降低等熵绝热效率；小喉部收缩比可显著提高等熵绝热效率、总压恢复系数以及总压比,但出口平均气流角也较大；随出/进口面积比降低,出口平均气流角、总压比及静压降低,等熵绝热效率及总压恢复系数升高；随来流相对马赫数增加,出口平均绝对马赫数、总压比及静压比均增加.,但等熵绝热效率总体上呈逐渐降低趋势。进气流道内气流的三维效应强烈,波阻损失及激波与附面层相互干扰导致附面层增厚、分离是导致流动损失增加的主要原因。各性能参数不会随进气流道几何参数的变化呈单调变化,所以必须对等熵绝热效率、总压比、静压比、总压恢复系数、出口平均气流角等性能参数进行折中选择,同时要结合压缩转子流量、压缩转子厚度等自身特点来确定综合性能较优的压缩转子。对于具有亚声速扩压段的Ram-rotor压缩转子,方案F1具有最高的总压比(12.2),方案F1-2的综合性能占优。对于Scrampressor压缩转子,随喉部收缩比的减小,总压比、静压比、等熵绝热效率及总压恢复系数均呈增加趋势；随隔板安装角的增加,等熵绝热效率及总压恢复系数增加,出口平均气流角减小,总压比及静压比呈缓慢下降趋势。附面层内低能流体的动能损失及多道激波损失是Scrampressor压缩转子喉部出口之前熵增的主要原因；结尾的曲线激波、附面层内的低能流体与主流掺混及附面层内低能流体横向迁移是Scrampressor压缩转子喉部出口之后熵增的主要原因。对于不具有亚声速扩压段的Scrampressor压缩转子,方案N3具有最高的等熵绝热效率(85.18%)及总压恢复系数(87.81%),而方案N1的综合性能占优。两种旋转冲压压缩转子的主要区别是Scrampressor压缩转子不具有扩压段,导致喉部之后的气流分离区的形成及出口气流参数不同。相同喉部收缩比或隔板安装角条件下,Scrampressor压缩转子具有较高的等熵绝热效率及较低的压缩能力,所以当压比增加满足要求并对等熵绝热效率需求较高的情况下,可以选择具有小喉部收缩比或大隔板安装的Scrampressor压缩转子。背压对两种结构的压缩转子的喉部稳定段之前的流场不造成影响。随着背压的增加,喉部出口后的气流分离区及激波串的位置前移,总压比均呈上升趋势,出口平均气流角均缓慢增加,Ram-rotor压缩转子的等熵绝热效率呈现先下降后升高的趋势,而Scrampressor压缩转子则表现为先增加再下降。相同背压条件下,Ram-rotor压缩转子的总压比和出口平均气流角较高,而Scrampressor压缩转子的等熵绝热效率较高。转速改变可显著影响压缩转子进气流道内的激波系结构,随转速增加,各道激波明显沿流向向后推移。从等熵绝热效率及总压恢复系数方面来看,Scrampressor压缩转子比Ram-rotor压缩转子更加优越。Ram-rotor压缩转子的出口绝对马赫数均为超声速,出口平均气流角较大；而Scrampressor压缩转子出口绝对马赫数均为亚声速,出口平均气流角较小。压缩转子的特性曲线均垂直于横坐标轴(质量流量),对于固定几何结构的压缩转子,其吸入的空气流量仅受转速影响；压缩转子的最高总压比均随转速的增加而增加,Scrampressor压缩转子压缩能力要弱于Ram-rotor压缩转子；总体上随转速的增加,压缩转子的等熵绝热效率呈下降趋势。在低转速时,Ram-rotor压缩转子容易进入不稳定工况；Scrampressor压缩转子的稳定裕度变化平缓,工况较稳定。更多还原

【Abstract】 Based on shock wave compression technology, the ram-rotor is a new compression system which uses the design of supersonic aircraft intake, the conventional axial-and centrifugal-flow compressor for reference. This kind of shock wave compression system has high pressure ratio, potential high efficiency, simple structure, light weight and less rotating parts. Over the past decade, it has much commercioganic to energy, power, transportation departments and researchers. Among numerous devices of distribution energy system which the core technology is the distribution electrical sources, the small gas turbines with low emission have the most commercial competitiveness, especially for the electrical industries which are changing towards the combination of large-scale power plant and mini type distribution power generation. The ram-rotor based on shock wave compression technology is one of research emphases of low emission small gas turbine. Research on this new efficient compression system has the important theoretical significance and practical application value. Some domestic scientific research institutions have developed relative study on ram-rotor, however, there still have a lot of works should be deeply developed.Firstly, the main factors affecting the ram-rotor performance are analyzed by theoretical methods in this paper. Secondly, basing on the theoretical analysis, many kinds of geometrical parameters are considered; CAD and FLUENT software are adopted to design the three-dimentional flow-path and simulate numerically the flow field of the ram-rotor and the Scrampressor; and the cases with best integrated performance are obtained. Furthermore, three-dimentional numerical simulation is adopted to study the flow field and the performance of two best cases at design point and off-design points. Systematic and comprehensive research data on the ram-rotor and the scrampressor are obtained which would establish a firm foundation for the further experimental study and practical application.For ram-rotor, the strake wall section with the positive trapezoid shape is better than that with the reversed trapezoid shape. Large or small throat length-height ratio can lead the adiabatic efficiency and the total pressure ratio decrease. The compression ramp angle and the subsonic divergent angle have no significant effect on the performance of the ram-rotor. Large strake straggle angle decreases the average flow angle at exit, the total pressure recovery coefficient and the total pressure ratio. The adiabatic efficiency is lower with larger or smaller strake straggle angle. Lower throat contract ratio can remarkably improve the adiabatic efficiency, the total pressure recovery coefficient, the total pressure ratio and the average flow angle at exit. With the decreasing of the exit-inlet area ratio, the average flow angle at exit, the total pressure ratio and the static pressure ratio decrease; but the adiabatic efficiency and the total pressure recovery coefficient increase. With the increasing of the relative Mach number, the average Mach number, the total pressure ratio and the static pressure ratio have an enhancive trend, and the adiabatic efficiency is the contrary. The three-dimensional effect is strong on the flow field and the main reasons of flow loss are caused by the shock wave loss, the interaction between the shock wave and boundary layer, and the boundary layer separation loss. All performance parameters do not change monotonously, so the reasonable compromises should be made among the adiabatic efficiency, the total pressure ratio, the static pressure ratio, the total pressure recovery coefficient, the average flow angle at exit, the width of the ram-rotor, the flow mass, and so on. For the ram-rotor with the diffuser, the case F1 has the highest total pressure ratio (12.2) and the case F1-2 has the best integrated performance.For the Scrampressor, the total pressure ratio, the static pressure ratio, the adiabatic efficiency and the total pressure recovery coefficient have the ascending trend with the decreasing of the throat contract ratio. The larger strake straggle angle increases the adiabatic efficiency and the total pressure recovery coefficient, decreases the average flow angle at exit, the total pressure ratio and the static pressure ratio. Shock wave loss and kinetic energy loss caused by the lower energy flow in the boundary layer are the main reasons of the entropy increasing before the throat exit. The final curve shock wave loss, the mixing loss between the low energy flow in the boundary larye and the main flow, the lateral migration of the low energy flow are the main reasons of the entropy increasing after the throat exit. For the scrampressor without the diffuser, the case N3 has the highest adiabatic efficiency (85.18%) and total pressure recovery coefficient (87.81%), and the case has the best integrated performance.The major difference between the ram-rotor and the scrampressor is the latter without the diffuser which causes the seperatioanal zone and the distinctness of performance at exit. Under the same throat contract ratio or strake straggle angle, the scrampressor has the higher adiabatic efficiency and the lower total pressure ratio than the ram-rotor. Therefore, scrampressor would be a good choice with smaller throat contract ratio and somewhat larger strake straggle angle when high adiabatic efficiency is needed.The back pressure almost does not affect the flow field before the throat exit. With the increasing of the back pressure, the position of flow separation zone moves towards the inlet; the total pressure ratio and the average flow angle at exit increase; the adiabatic efficiency of the ram-rotor decreases firstly and then increases, and that of the scrampressor increases firstly and then decreases. Under the same back pressure, the ram-rotor has the higher total pressure ratio and the average flow angle, but the scrampressor has the higher adiabatic efficiency.The rotational speed can significantly change the shock wave structure. With the increasing of the rotational speed, the shock wave will move towards the exit. Under the same rotational speed, the scrampressor is superior to the ram-rotor at a certain extent, such as the adiabatic efficiency, the total pressure recovery coefficient.The characteristic curves of the ram-rotor and the scrampressor are perpendicular to the abscissa axis, namely, the flow mass can be affected only by the rotational speed. The highest total pressure ratio increases with the increasing of the rotational speed. The compression ability of the scrampressor is weaker than the ram-rotor, and the total trend of the adiabatic efficiency is degressive. At the lower rotational speed, the ram-rotor could enter into the unsteady state easily, but the stability margin of the scrampressor changes mildly and keeps a good working status.更多还原