超超临界循环流化床锅炉水冷壁并联管流动不稳定性计算分析  

Calculation of flow instability in water wall parallel tubes of ultra-supercritical CFB boiler

作　　者：高琴[1] 肖峰[1] 许秀启[1] 罗勇军 黄建荣[1] 欧阳诗洁 杨冬[2] GAO Qin;XIAO Feng;XU Xiuqi;LUO Yongjun;HUANG Jianrong;OUYANG Shijie;YANG Dong(Shanghai Boiler Works Co.,Ltd.,Shanghai 200245,China;State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]上海锅炉厂有限公司,上海200245 [2]西安交通大学动力工程多相流国家重点实验室,陕西西安710049

出　　处：《热力发电》2020年第5期81-88,共8页Thermal Power Generation

基　　金：国家重点研发计划项目(2016YFB0600204-02)。

摘　　要：本文建立了一个基于时域分析方法的数值计算模型,对均匀加热并联管系统的流动不稳定性进行了计算和分析。在程序验证的基础上,对流体在超超临界循环流化床(CFB)锅炉水冷壁中的非线性动态特征量进行了计算。结果表明,管道进出口的质量流量脉动趋势呈反相分布。在并联系统任意一个管道上施加热扰动,双管进出口质量流量均随时间呈逐渐下降趋势,这说明超超临界CFB锅炉在正常满负荷工况下可以保持流动稳定。在强加热通道上施加扰动时,并联双管的进口质量流量峰值都较在弱加热通道上施加热扰动更大。此外,强加热管比弱加热管在热扰动下展现出更显著的动态特性。通过对不同进口温度和进口质量流量的工况进行计算,得到了基于无量纲数的流动不稳定边界,并对系统参数对不稳定边界的影响作出了相应分析。结果表明:当进口温度较低时,提高进口质量流量将大大增加系统的流动稳定性;当进口温度较高时,进口质量流量对不稳定边界的影响几乎可以忽略不计。In this study,a numerical model that applies time-domain method is established to analyze the flow instability of a uniformly heated parallel-channel system.On the basis of program verification,the nonlinear dynamics of the fluid in water wall of ultra-supercritical circulating fluidized bed(CFB)boilers are discussed.The results show that,the fluctuating trend of the mass flow at inlet and outlet of the chanel is in inverse distribution.The mass flow rates with heat flux perturbations imposed on either single channel decline gradually with time,suggesting that flow stability can be maintained under normal full load condition.In addition,the effects of heat flux perturbation on transient responses of the typical parallel channels are studied.The results illustrate that the maximum of the inlet mass flow rate in both channels are high when perturbation is imposed on a strong heated channel.Moreover,flow in the stronger heated channel reveals more remarkable dynamic characteristics than in the weaker one.Furthermore,data at different inlet temperatures and mass flow rates are calculated to generate the dimensionless instability boundary.The results show that,when the inlet temperature is low,the inlet mass flow rate should be increased to stabilize the system.Otherwise,the effect of the mass flow rate on the instability boundary is almost negligible.

关 键 词：超超临界 CFB锅炉 水冷壁 并联管 热负荷扰动 流动不稳定性 

分 类 号：TK123[动力工程及工程热物理—工程热物理]