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燃气轮机燃烧室出口燃气温度场分布严重不均匀,其中燃气流的高温核心即热斑会加剧燃气透平内部非定常流动和传热的复杂性,引起叶栅的局部过热甚至烧蚀,从而降低透平的可靠性和寿命。研究并揭示热斑迁移机制对于透平叶栅高效冷却技术及非定常气动优化设计方法的发展至关重要。文中综述了燃气透平进口热斑迁移及其影响机制的研究现状及进展,着重介绍了燃烧室特性参数、叶型结构和冷气对热斑迁移的影响规律。有关热斑现象的研究虽然取得一定进展,但尚需要更深入的试验和数值研究,文中指出:目前试验和数值研究中广泛采用的圆形热斑与实际情况差异较大,需要在燃烧室真实出口温度场下实现透平非定常流场和传热的精确测量;关于燃烧室特性参数对热斑迁移影响的研究未考虑湍流强度和旋流等流场特征的影响且缺乏试验数据;叶型结构对热斑迁移影响的研究才刚刚开始,需要对热斑与叶排间的“时序效应”及其对叶栅热负荷和透平整体性能的影响机制开展深入的试验研究;最后,还需要对冷却气流与热斑干涉作用及其引起的透平非定常气热性能的变化进行试验和数值研究,从而为透平的高效冷却和气动传热优化设计奠定理论基础。
Gas temperature distribution at the exit of gas turbine combustor is seriously uneven. Hot spot, which is the high temperature core of gas flow, can aggravate the unsteady flow and heat transfer complexity in the gas turbine, causing local overheating and even ablation of cascades, Flat reliability and longevity. Studying and revealing the hot spot migration mechanism is very important for the development of turbine cascade efficient cooling technology and unsteady aerodynamic design method. In this paper, the research status and progress of hot air spot transfer and its influence mechanism of gas turbine are summarized. The influence of combustion chamber parameters, airfoil structure and cold air on hot spot migration are emphatically introduced. Although some progress has been made in the study of hot spot phenomenon, more in-depth experimental and numerical studies are still needed. The paper points out that the circular hot spot widely used in the current experiments and numerical studies is quite different from the actual situation, Outlet temperature field to achieve accurate measurement of unsteady flow field and heat transfer in the turbine. The study on the influence of combustion chamber parameters on the hot spot migration did not consider the influence of turbulence intensity and the characteristics of the flow field, such as the swirling flow, and lacked the experimental data. The study of the effect of structure on the hot spot migration has just begun. It is necessary to conduct an in-depth experimental study on the “time-series effect” between the hot spot and the leaf row and its influence on the thermal load and the overall performance of the turbine. Finally, It is also necessary to conduct experiments and numerical studies on the interaction between the cooling airflow and the hot spot and the thermal performance of the turbine caused by the unsteady gas turbine, so as to lay a theoretical foundation for the optimization design of the turbine for efficient cooling and pneumatic heat transfer.