135 MW CFB锅炉L形屏式过热器热偏差分析  

Analysis of Thermal Deviation in L-type Platen Superheaters of a 135 MW CFB Boiler

作　　者：金鑫[1] 马有福[1] 吕俊复[2] JIN Xin;MA Youfu;Lü Junfu(Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University,Beijing 100084,China)

机构地区：[1]上海理工大学上海市动力工程多相流动与传热重点实验室,上海200093 [2]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《动力工程学报》2020年第3期169-176,共8页Journal of Chinese Society of Power Engineering

基　　金：国家重点研发计划资助项目(2016YFB0600203)。

摘　　要：以一台135 MW CFB锅炉的L形屏式过热器为例,对其热偏差产生机理进行了研究。通过建立热偏差计算模型和自主编制的软件,计算和分析了其同屏及屏间热偏差系数。结果表明:在同屏管组的引入引出管采用Z形布置时,集箱效应与管组内外侧管长结构不均匀对流量分配的影响相互抵消,达到了流量均匀分配的效果,同屏热偏差主要受结构不均匀和热负荷分布的影响;在各管组引入引出管的进出口集箱采用Z形布置时,由于集箱效应,屏间流量分配明显不均,这是造成屏间热偏差的主因;在实际应用中,应充分利用集箱效应对屏内及屏间工质流量分配的影响,使管内工质流量分配与管外热负荷分布相互配合,达到控制屏式过热器热偏差的目的。A study was conducted on the generation mechanism of thermal deviation in the L-type platen superheaters of a 135 MW CFB boiler.By establishing a prediction model of thermal deviation and based on the self-developed software,the thermal deviations in the same platen and among different platens were calculated and analyzed.Results show that when Z-type arrangement is adopted for the steam lead-in pipe and lead-out pipe in the same platen,the header effect and the non-uniform lengths and structures of inner and outer tubes in the tube bundle could balance out their effects on the flow distribution,i.e.the thermal deviation in the same platen is mainly caused by the non-uniform structure and the non-uniform heat flux distribution.When Z-type arrangement is also adopted for the inlet header of lead-in pipes and the outlet header of lead-out pipes,the flow distribution among platens is obviously non-uniform due to the header effect,which contributes a lot to the thermal deviation among platens.In practical applications,it is suggested making full use of the header effect on the flow distribution in the same platen and among different platens,i.e.,making the flow distribution of working fluids in the tubes balance the heat flux distribution outside the tubes,thus achieving a well control on the thermal deviation in L-type platen superheaters.

关 键 词：循环流化床锅炉 屏式过热器 并联管组 热偏差 流量偏差 

分 类 号：TK224[动力工程及工程热物理—动力机械及工程]