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一、前言汽轮机低压末级长叶片在高背压小容积流量下安全经济运行,是发展大功率供热、调峰、空冷机组的关键技术问题。长叶片在小容积流量下运行,效率显著降低,伴随着容积流量的减少,叶根产生倒流,叶顶产生旋涡,动应力水平增高,排汽部分过热,甚至发生失速颤振而造成叶片断裂事故。为了保障末级叶片的可靠性,必须从理论和试验方面详细研究末级流场、温度场及叶片振动特性。哈尔滨汽轮机厂六十年代设计的拱型围带665毫米长叶片广泛的应用于高压5、10、20万千瓦各型机组上,这种叶片在机组深度变工况下运行的可靠性是大家十分关心的问
I. Preface The low-pressure end-stage long blades of steam turbines operate safely and economically under high backpressure and low volume flow, which is a key technical issue for developing high-power heat supply, peak shaving and air-cooled units. Long leaves run at a small volumetric flow rate, the efficiency is significantly reduced, with the decrease of volume flow, leaf roots produce backflow, leaf vortex vortex, increased dynamic stress level, the exhaust part of the overheating, and even stall flutter caused by blade fracture accident . In order to ensure the reliability of the last blade, the final flow field, temperature field and blade vibration characteristics must be studied theoretically and experimentally. Harbin Steam Turbine Plant The sixties designed arcuate shroud 665 mm long blade is widely used in high-pressure 510,000 kilowatts of various types of units, the reliability of the operation of this type of blade in the deep variable working conditions is very good Concerned about the question