汽轮机末级叶片模态振型与变负荷动应力的三维数值模拟
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摘要
火电机组参与电网深度灵活调峰已成为当代电力发展的新常态,在机组低负荷深调过程中,蒸汽流量较小。本文针对调峰机组汽轮机末级叶片小容积流量问题进行了模态特性及动应力响应进行数值模拟研究,结果表明:末级叶片在2 820～3 090 rpm之间无共振点,而额定温度范围内整圈叶片无共振转速;以模态分析为基础综合考虑变温特性下得出叶片伸长量,可为现场叶片汽封调整作为参考。基于额定工况与2.2 kPa、40 t/h工况下的动应力满足设计要求,而其他非设计工况下的动应力已超出了叶片的耐振强度,全工况动静应力极值均处于叶型根部出汽侧,导致叶片的耐振强度许用值较低。上述数值结果为电厂调试提供了理论支撑,同时也为机组经济性运行作出了技术指导。
It has become a normal state of modern power development that the participation of thermal power units in the depth and flexible peak shaving of the power grid. In this process, the steam flow of unit is small. In this paper, the modal characteristics and dynamic stress response of turbine last blade with small volume flow are numerically simulated.The results show that the last blade has no resonance point between 2 820～3 090 rpm, and the whole temperature range maintained in a rated temperature range, in which blade has no resonance speed. Based on the modal analysis, the blade elongation is obtained by comprehensively considering the temperature change characteristics, which can be used as a reference for the adjustment of blade seal. In view of the dynamic stress of rated working condition and 2.2 kPa,40 t/h working condition, the design requirement were reached, while the dynamic stress of other non-design working condition had exceeded the blade's anti-vibration strength, meanwhile the extreme values of dynamic and static stresses were at the outlet side of the blade root, which resulted in a lower allowable value of blade vibration resistance. The above numerical results could not merely provide.
It has become a normal state of modern power development that the participation of thermal power units in the depth and flexible peak shaving of the power grid. In this process, the steam flow of unit is small. In this paper, the modal characteristics and dynamic stress response of turbine last blade with small volume flow are numerically simulated.The results show that the last blade has no resonance point between 2 820～3 090 rpm, and the whole temperature range maintained in a rated temperature range, in which blade has no resonance speed. Based on the modal analysis, the blade elongation is obtained by comprehensively considering the temperature change characteristics, which can be used as a reference for the adjustment of blade seal. In view of the dynamic stress of rated working condition and 2.2 kPa,40 t/h working condition, the design requirement were reached, while the dynamic stress of other non-design working condition had exceeded the blade's anti-vibration strength, meanwhile the extreme values of dynamic and static stresses were at the outlet side of the blade root, which resulted in a lower allowable value of blade vibration resistance. The above numerical results could not merely provide.
引文
[1]王兴国,时珉,尹瑞,等.火电机组参与电力调峰辅助服务策略研究[J].河北电力技术,2018(6):1-4.
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[8]姜伟,谢诞梅,陈畅,等.基于时域分析法的汽轮机末级叶片颤振预测及分析[J].振动与冲击,2015,34(11):194-199.
[9]吉桂明.小流量工况对汽轮机末级动叶的侵蚀[J].热能动力工程,2009(2):246-246.
[10]黄晨,武广富,郑威.火电机组灵活性提升技术研究[J].电站系统工程,2018,34(3):14-16,20.
[11]王力,陈永辉,李波,等.300 MW机组高背压供热改造方案及试验分析[J].汽轮机技术,2018,60(5):385-388.
[2]M.L.Kubik,P.J.Coker,J.F.Barlow.Increasing thermal plant flexibility in a high renewables power system[J].Applied Energy,2015(154):102-111.
[3]宁剑,谢旭,吴继平,等.基于单场及场群模式的新能源有功调节能力研究[J].电网与清洁能源,2018,34(10):69-75.
[4]亢岚,杨培宏,韩小峰,等.提高风电渗透率的电力系统多目标优化调度研究[J].电网与清洁能源,2017,33(3):97-103,118.
[5]刘娆.汽轮机高背压供热改造的方式[J].机械工程师,2017(9):135.
[6]龚胜,石奇光,冒玉晨,等.我国火电机组灵活性现状与技术发展[J].应用能源技术,2017(5):1-6.
[7]侯玉婷,李晓博,刘畅,等.火电机组灵活性改造形势及技术应用[J].热力发电,2018,47(5):8-13.
[8]姜伟,谢诞梅,陈畅,等.基于时域分析法的汽轮机末级叶片颤振预测及分析[J].振动与冲击,2015,34(11):194-199.
[9]吉桂明.小流量工况对汽轮机末级动叶的侵蚀[J].热能动力工程,2009(2):246-246.
[10]黄晨,武广富,郑威.火电机组灵活性提升技术研究[J].电站系统工程,2018,34(3):14-16,20.
[11]王力,陈永辉,李波,等.300 MW机组高背压供热改造方案及试验分析[J].汽轮机技术,2018,60(5):385-388.