化工学报 ›› 2017, Vol. 68 ›› Issue (9): 3388-3396.DOI: 10.11949/j.issn.0438-1157.20170678

• 流体力学与传递现象 • 上一篇    下一篇

汽轮机动叶栅顶部通道湿蒸汽超声速凝结流动特性

韩旭, 韩中合   

  1. 华北电力大学电站设备状态监测与控制教育部重点实验室, 河北 保定 071003
  • 收稿日期:2017-05-25 修回日期:2017-06-26 出版日期:2017-09-05 发布日期:2017-09-05
  • 通讯作者: 韩中合
  • 基金资助:

    国家科技支撑计划项目(2014BAA06B01);中央高校基本科研业务费专项资金项目(2016XS106)。

Supersonic condensation flow characteristics of wet steams in turbine rotor blade tip section

HAN Xu, HAN Zhonghe   

  1. Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, North China Electric Power University, Ministry of Education, Baoding 071003, Hebei, China
  • Received:2017-05-25 Revised:2017-06-26 Online:2017-09-05 Published:2017-09-05
  • Contact: 10.11949/j.issn.0438-1157.20170678
  • Supported by:

    supported by the National Science and Technology Support Program (2014BAA06B01) and the Fundamental Research Funds for the Central Universities (2016XS106).

摘要:

由于汽轮机内高速凝结流动的复杂性,目前还没有一个得到普遍公认的凝结成核模型,且现有数值模型通常忽略汽液相间滑移。针对叶栅通道内凝结参数分布陡峭、变化敏感的特点,采用既能准确描述可压缩气体跨声速流动又能捕捉参数突跃的双流体数值模型,对汽轮机动叶栅顶部通道内的凝结流动特性进行分析。揭示压比对湿蒸汽非平衡凝结特性的影响,归纳了叶片表面压力、成核率、湿度、水滴数的变化规律。研究表明:各工况压力面的压比计算值与实验数据吻合较好,但吸力面后半段存在一定误差;双流体数值模型适用于过热工况和入口过冷度较小的凝结工况,但当入口过冷度较大时,几乎无法捕捉到凝结激波导致的压力突跃;激波干涉和涡团掺混也会对水滴分布产生较大影响。

关键词: 湿蒸汽, 汽轮机, 超声速, 两相流, 凝结, 热力学

Abstract:

Steam turbines are critical power generation equipment in electric power industry. Understanding water vapor condensation flow is important to improve efficiency and safety of steam turbines. Due to complexity of high speed condensation flow in steam turbines, no universally accepted nucleation model is available at present and current numerical models usually neglect vapor-liquid slip. Considered steep distribution and change sensitivity of condensing parameters, a double fluid numerical model of shear stress transport (SST) k-ω-kd two-phase turbulence, which can not only describe transonic flow of compressible gas accurately but also capture parameter jump instantly, was used to analyze condensation flow characteristics in turbine rotor blade tip section. The study revealed influence of pressure ratio on non-equilibrium condensation flow characteristics of wet steams and summarized changing patterns of surface pressure, nucleation rate, humidity, and number of water droplets. Results showed that calculation of pressure ratio at compression surface was in good agreement with experimental data under various operating conditions, although some error was observed in the second half of suction surface. The two fluid numerical model was applicable to both overheating operation and condensations with slight overcooling inlet. But pressure jump caused by condensation shock could hardly be caught for large overcooling inlet. Shock wave interference and vortex mixing had a great influence on distribution of water droplets.

Key words: wet steam, steam turbine, supersonic, two-phase flow, condensation, thermodynamics

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