摘要
在600 MW超临界CFB水冷壁变负荷实际运行条件下,以水冷壁实际采用的Φ28.6×5.8 mm的4头内螺纹管为研究对象,在高压汽水两相流回路上对垂直并联管中汽液两相流压力降型不稳定进行了试验研究。确定了压力、质量流速、进口过冷度以及上游可压缩容积对垂直并联内螺纹管两相流压力降型脉动的影响。结果表明,随压力增大,发生脉动的临界热负荷增加,界限干度逐渐升高,系统稳定性增强,脉动周期先变长后变短,脉动的振幅逐渐减小。本试验中,当压力P>6 MPa时,就不再有压力降脉动发生;随着质量流速的增加,脉动发生的界限热负荷升高,而脉动的周期减小;进口过冷度对密度波脉动呈现单值性影响,随进口过冷度增加,界限热负荷单调增加,界限干度的变化表现出不同的趋势,在较低的质量流速下,随着过冷度的增加,界限干度单调下降;在较高的质量流速下,随着过冷度的增加,界限干度单调上升;上游可压缩容积对界限热负荷的影响较小,随充气比的增大,脉动的周期和幅值逐渐增大。
Under the practical load-variation operating condition of a 600 MW supercritical CFB(Circulating Fluidized Bed) water wall and with the actually-used Φ28.6×5.8 4-head inner threaded tubes in the water wall serving as an object of study,experimentally studied was the pressure drop instability of the gas-liquid twophase flow in vertical parallel tubes of HP steam-water two-phase flow loops.Determined was the influence of pressure,mass flow speed,inlet supercooling degree and upstream compressible volume on the pressure drop pulsation of the above tubes.The research results show that with an increase of the pressure,the critical heat load at which a pulsation occurs will increase,the limit dryness will gradually go up,and the system stability will be improved.The pulsation period will be first extended and then shortened with the amplitude of the pulsation being gradually diminished.In the present experiment,when the pressure is greater than 6 MPa,no pressure drop pulsation will occur.With an increase of the mass flow speed,the limit heat load at which a pulsation occurs will increase while the pulsation period will diminish.The inlet supercooling degree will exercise a monodromy influence over the density wave pulsation.With an increase of the inlet supercooling degree,the limit heat load will monotonically increase and the change of the limit dryness will exhibit different tendencies.At a relatively low mass flow speed,with an increase of the supercooling degree,the limit dryness will diminish monotonically.At a relatively high mass flow speed,with an increase of the supercooling degree,the limit dryness will rise monotonically.The upstream compressible volume will have a relatively small influence on the limit heat load.With an increase of the gas-filling ratio,the pulsation period and amplitude will also gradually increase.
出处
《热能动力工程》
CAS
CSCD
北大核心
2009年第6期741-745,共5页
Journal of Engineering for Thermal Energy and Power
基金
国家自然科学基金资助项目(10975111)
关键词
超临界
循环流化床
低质量流速
垂直并联内螺纹管
汽-液两相流
压力降脉动
supercritical,circulating fluidized bed,low-mass flow speed,vertical parallel inner threaded tube,gas-liquid two-phase flow,pressure-drop pulsation
