超音压气机转子的起动特性及内部流动组织研究

发布时间：2018-01-17 23:02

本文关键词：超音压气机转子的起动特性及内部流动组织研究　出处：《中国科学院工程热物理研究所》2017年博士论文　论文类型：学位论文

【摘要】：随着级负荷的不断增加,超音转子进口相对马赫数不断提高,当进口相对马赫数超过1.75左右时,转子的起动问题和高速来流的高效减速增压问题成为了限制转子性能的关键。本文从超音平面叶栅的叶型设计出发,对进口相对马赫数较高的内激波式转子的起动特性及内部流动组织问题进行了研究,涉及的主要内容如下:1、围绕超音平面叶栅的唯一攻角特性、起动点的计算、流道内波系结构的优化组织等问题,对超音平面叶栅的流动机理进行了研究。首先,基于对超音平面叶栅极限特征线上游流场的分析,提出了超音平面叶栅的外伸波损失计算模型。其次,提出了一种简单的方法来模拟超音平面叶栅处于起动点时喉口前的主要流场结构,利用该方法研究了不同类型的叶栅处于起动点时喉口前的总压恢复系数随来流马赫数的变化,将相关结果与本文提出的理想化的起动过程相结合,建立了叶栅起动点的计算方法。再次,针对起动工况下的前缘内伸波,建立了模型来计算其形状。最后,以激波损失最小为原则,研究了超音平面叶栅流道内的波系优化组织问题,明确了仅在喉口前的斜激波系的损失为零的理想情况下,斜激波系和结尾激波组成的波系的损失取得最小值。2、依据超音平面叶栅流动机理的研究成果,提出了超音平面叶栅叶型的参数化设计方法。利用该方法设计了相关叶型,与实验数据或数值模拟结果的对比表明,采用本文提出的设计方法能够对超音平面叶栅的起动点、唯一攻角特性以及流道内的波系结构进行有效的控制。在此基础上,研究了该设计方法中关键控制参数对超音平面叶栅气动性能的影响。3、针对超音转子,本文以通流面积的轴向变化率不变为原则,提出了超音平面叶栅叶型向转子回转面叶型转换的关系式,完善了超音转子的气动设计方法。以采用这种设计方法设计的超音转子为研究对象,通过数值模拟,对超音转子的起动特性进行了研究,分析了各叶高叶型的起动点和对应的平面叶栅的起动点不同的原因。同时,转子气动性能的研究结果表明,转子流场中各激波的强度得到了有效控制,设计点的性能和设计目标符合较好。4、开展了超音转子内部流动特性的研究,分析了叶表边界层内气流的径向输运、叶顶泄漏流、分离流对流场的影响。结果表明,在结尾激波的作用下,下游叶表边界层内气流的径向输运强度大幅增加,这虽然使叶根附近结尾激波与边界层相互作用引起的流动分离区显著减小,但导致了机匣附近的边界层增厚。厚度明显增加的边界层在和结尾激波作用后,发生了明显的分离。随后,在与分离涡和泄漏涡的共同作用下,靠近压力面的叶尖角区的高熵区影响范围不断扩大。
[Abstract]:With the increasing of the stage load, the relative Mach number of the inlet of the supersonic rotor increases continuously, when the relative Mach number of the inlet exceeds about 1.75. The starting problem of rotor and the problem of high efficiency deceleration and supercharging of high speed flow have become the key to limit the performance of rotor. In this paper, the blade shape design of supersound plane cascade is introduced. The starting characteristics and internal flow structure of the inner shock rotor with relatively high Mach number are studied. The main contents are as follows: 1, the unique angle of attack around the supersound plane cascade. The flow mechanism of the supersound plane cascade is studied by calculating the starting point and optimizing the structure of the internal wave system of the channel. Firstly, the upstream flow field of the limit characteristic line of the supersound plane cascade is analyzed. A model for calculating the outreaching wave loss of a supersound planar cascade is proposed. Secondly, a simple method is proposed to simulate the main flow field structure in front of the throat when the supersound planar cascade is at the starting point. By using this method, the change of total pressure recovery coefficient in front of the throat of different types of cascades at the starting point is studied, and the correlation results are combined with the idealized starting process proposed in this paper. The method of calculating the starting point of cascade is established. Thirdly, the model is established to calculate the shape of the leading edge wave in the starting condition. Finally, the principle of minimum shock loss is taken as the principle. In this paper, the optimal structure of the wave system in the channel of the supersound plane cascade is studied, and it is clear that the ideal condition is that the loss of the oblique shock system in front of the throat is zero. The loss of the oblique shock system and the wave system composed of the end shock wave is minimum. 2, according to the research results of the supersound plane cascade flow mechanism. A parameterized design method for supersound planar cascade blade is presented. The relative blade profile is designed by using this method, and the results are compared with experimental data or numerical simulation results. The design method presented in this paper can effectively control the starting point, the unique angle of attack and the structure of the wave system in the channel. The influence of key control parameters on the aerodynamic performance of supersound planar cascade is studied. The axial change rate of flow area is not changed to the principle of supersound rotor. The relationship between the supersound plane cascade blade and the rotor rotary blade shape is proposed, and the aerodynamic design method of the supersound rotor is improved. The supersound rotor designed by this design method is taken as the research object, and the numerical simulation is carried out. The starting characteristics of supersound rotor are studied, and the causes of different starting points of each blade type and corresponding plane cascade are analyzed. The results show that the aerodynamic performance of the rotor is different. The intensity of shock waves in rotor flow field is effectively controlled, and the performance and design target of design point are in good agreement with .4. the study on the internal flow characteristics of supersound rotor is carried out. The influence of radial air flow, tip leakage flow and separation flow on the flow field in the blade surface boundary layer is analyzed. The results show that the radial transport intensity of the downstream blade surface boundary layer increases greatly under the action of the end shock wave. Although the flow separation zone caused by the interaction between the end shock wave and the boundary layer near the leaf root decreases significantly, it leads to the thickening of the boundary layer near the casing and the obvious increase of the thickness of the boundary layer after the action of the end shock wave. Then the influence range of the high entropy region near the pressure surface in the tip region of the leaf is continuously expanded under the joint action of the separation vortex and the leakage vortex.
【学位授予单位】：中国科学院工程热物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：V231

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