超临界CFB锅炉灵活运行方式下的流动传热及动态特性试验研究  

Experimental investigation on flow heat transfer and dynamic characteristics of supercritical CFB boiler under flexible operation

作　　者：杜晓成 王奥宇 项昱轩 杨冬[1] DU Xiaocheng;WANG Aoyu;XIANG Yuxuan;YANG Dong(State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]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》2023年第9期76-86,共11页Thermal Power Generation

基　　金：国家重点研发计划项目(2022YFB4100303)。

摘　　要：为了给超临界350 MW循环流化床(CFB)锅炉灵活运行提供指导,对亚临界压力下垂直上升光管内低质量流速汽水工质的流动传热及动态特性进行了试验研究。流动传热试验的压力为12.0~15.0 MPa,质量流速为350~440 kg/(m^(2)·s),内壁热负荷为135~220 kW/m^(2)。在26 MPa稳态试验基础上,通过压力阶跃减小和热负荷阶跃增加研究了垂直上升光管的动态特性。流动传热试验的结果表明:改变压力会影响饱和沸腾区的传热性能和饱和沸腾区的焓值区间;质量流速对传热性能影响仅体现在过冷区,质量流速增大过冷区的传热性能增强;增加热负荷会使饱和沸腾区的传热性能下降。根据流动传热试验数据,拟合得到了亚临界条件下垂直上升光管内汽水工质的传热和摩擦阻力关联式。动态特性试验的结果表明:压力阶跃变化量越大,试验段内的质量流速增量越大,出口比焓和出口壁温变化程度越大;热负荷阶跃仅会影响出口比焓,热负荷阶跃变化量越大,出口比焓和出口壁温变化程度越大。本研究可以为超临界CFB锅炉低负荷、灵活运行过程提供指导。To provide guidance for the flexible operation of 350 MW supercritical CFB boiler,experimental investigations were conducted on the flow and heat transfer characteristics of water with low mass flux in vertical upward smooth tube under subcritical pressure.Flow and heat transfer experiments were performed under the conditions of 12~15 MPa pressure,350~440 kg/(m^(2)·s)mass flux,135~220 kW/m²inner wall heat flux.Furthermore,the dynamic characteristics of the tube were experimentally studied by decreasing pressure and increasing inner wall heat flux,based on the 26 MPa heat transfer experiments.The results of the heat transfer experiments indicate that changing pressure affects the heat transfer performance and enthalpy range of the saturated boiling region.The influence of mass flux on heat transfer performance is only reflected in the sub cooled zone,and the heat transfer performance is enhanced with the increase of mass flux.Increasing heat flux decreases the heat transfer performance in the saturated boiling region.Meanwhile,the correlations of the heat transfer coefficient and friction resistance of water in the tube were fitted based on the experimental data.The dynamic experimental results show that the greater the pressure step,the greater the mass flux increment,and the greater the change in the outlet enthalpy and outlet wall temperature.The step of heat flux only affects the outlet enthalpy and outlet wall temperature.The greater the step of heat flux,the greater the change in the outlet enthalpy and outlet wall temperature.This work can provide guidance for supercritical CFB boiler in low load and flexible variable load operation.

关 键 词：CFB锅炉 灵活运行 流动传热特性 动态特性 关联式 垂直上升光管 

分 类 号：TM621.2[电气工程—电力系统及自动化]