高压压气机级间引气的流场数值研究

发布时间：2018-03-16 23:38

本文选题：高压压气机　切入点：数值模拟　出处：《上海交通大学》2012年硕士论文　论文类型：学位论文

【摘要】：轴流压气机作为航空燃气涡轮发动机的核心部件之一,其运行效率和稳定性对发动机的性能起着重要影响。从发动机的高压压气机中进行引气,是保证发动机正常运行和满足飞机飞行需求的必要环节。从压气机引出压力、温度不同的空气,可用于机舱供气、飞机防冰、涡轮冷却、间隙密封、提供油箱及附件设备的高压环境等多个方面。同时,在发动机启动、停机以及非设计工况运行时,合理的引气可以有效防止机组发生失速和喘振。引气无疑会改变压气机的工作状态,从而影响发动机的工作状态。因此,为了保障发动机的正常工作,有必要研究引气对压气机的影响。本文利用流场数值模拟软件,以三级半轴流高压压气机为研究对象,探索了引气结构、位置和引气流量对压气机性能和流场的影响。首先,为保证数值计算过程的稳定性以及结果的准确性,综合考察了网格规模、拓扑形式、差分格式和湍流模型对数值计算过程的影响,在此基础上确定了后续引气研究中采用的网格、差分格式和湍流模型。其次,研究了无引气和有引气情形下压气机的性能和流场。结果表明,引气使主流进口流量增大,主流出口流量减小;压气机的等熵效率增大、总压比减小。引气吸除了端壁附近的高熵流体,明显改善了引气位置相邻的两列叶片在叶顶区域的损失。引气还明显地改变了下游叶片的进口气流角,从而改变了级与级间的匹配特性。再次,为研究引气结构和引气位置的影响,构建了通流面积相同、但进口形状和引气位置不同的引气槽。数值计算的结果表明:引气位置对压气机性能的影响较为显著。在不同的周向引气位置中,在叶片尾缘下游引气的影响最好,在压力面侧引气的影响最差。在不同的轴向位置中,在级与级之间引气的影响较好,在叶栅流道中间引气的影响较差。最后,探索了压气机性能和流场的变化与引气流量间的关系。结果表明:引气流量对压气机性能的影响受到压气机本身所处工作点的影响:在高转速下,效率随着引气流量的增大而明显地增大,而在低转速下,效率并没有随引气流量的增大而明显地增大。
[Abstract]:As one of the core components of the aeronautical gas turbine engine, the axial flow compressor has an important effect on the performance of the engine. It is necessary to ensure the normal operation of the engine and meet the flight requirements of the aircraft. The pressure is extracted from the compressor and the air at different temperatures can be used in the engine room for air supply, aircraft anti-ice, turbine cooling, clearance sealing, Provides high pressure environment for fuel tank and accessories. At the same time, when engine starts, stops and runs off-design, Reasonable air entrapment can effectively prevent the stall and surge of the unit. The exhaust will undoubtedly change the working state of the compressor and thus affect the working state of the engine. Therefore, in order to ensure the normal operation of the engine, It is necessary to study the effect of air entrainment on compressor. In this paper, the effects of entrainment structure, position and flow rate on the performance and flow field of a three-stage semi-axial high pressure compressor are studied by using the numerical simulation software of flow field. In order to ensure the stability of the numerical calculation process and the accuracy of the results, the effects of grid size, topological form, difference scheme and turbulence model on the numerical calculation process are comprehensively investigated. On this basis, the mesh, difference scheme and turbulence model used in the subsequent air-entraining research are determined. Secondly, the performance and flow field of compressor without and without air entrainment are studied. The results show that the main stream inlet flow rate increases, the mainstream outlet flow rate decreases, and the isentropic efficiency of compressor increases. The total pressure ratio is reduced. The high entropy fluid near the end wall is sucked by the entrainer, which obviously improves the loss of the two rows of blades adjacent to the entrainment position in the top of the blade. The inlet air angle of the downstream blade is also obviously changed by the air entrainment. Thus, the matching property between stages is changed. Thirdly, in order to study the influence of entrainment structure and air entrainment position, the same flow passage area was constructed. The numerical results show that the influence of the entrainment position on the compressor performance is significant. In the different circumferential air entrainment positions, the air entraining at the lower edge of the blade tail edge is the best. In different axial positions, the effect of air entraining between stages and stages is better than that between cascades. Finally, the relationship between the performance of compressor and the variation of flow field and air entrainment flow rate is explored. The results show that the effect of air entrainment flow on compressor performance is affected by the working point of the compressor itself: at high speed, The efficiency increases obviously with the increase of the entrainment flow rate, but does not increase obviously with the increase of the entrainment flow rate at low rotational speed.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH45

【参考文献】