超临界CFB锅炉深度调峰跨临界过程中水冷壁动态特性的试验研究  

Experimental investigation on dynamic characteristics of water wall during transcritical process of deep peak regulation for supercritical CFB boilers

作　　者：卿浩 周妍君 宋园园 杨冬[1] 黄中[2] 吕俊复[2] QING Hao;ZHOU Yanjun;SONG Yuanyuan;YANG Dong;HUANG Zhong;LYU Junfu(State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,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 [2]清华大学能源与动力工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《热力发电》2023年第9期29-38,共10页Thermal Power Generation

基　　金：国家重点研发计划项目(2022YFB4100303)。

摘　　要：为了保证超临界循环流化床(CFB)锅炉具有良好的宽负荷运行特性及深度调峰的能力,对跨临界压力变化时工质与水冷壁间的动态特性进行试验研究。采用Φ25.0 mm×3.5 mm的垂直上升光管,在压力20.0~23.0 MPa,质量流速400~800 kg/(m^(2)·s)试验工况范围内开展了近临界稳态传热试验和跨临界压力阶跃动态特性试验。结果表明:近临界压力下,增大质量流速、减小内壁热负荷、降低压力都能使传热恶化发生时的干度减小,对应的流体焓值增大,使传热恶化推迟发生;跨临界压力阶跃变化时,受热管内流体可能发生传热恶化导致壁温飞升,但随着质量流速的增大温度又回落到正常值;壁温飞升点与内壁面的传热随时间依次经历传热恶化阶段,过冷沸腾传热强化阶段和单液相换热阶段;各参数对跨临界压力阶跃变化时传热恶化的影响与对近临界稳态试验的传热恶化的影响相同,质量流速减小和内壁热负荷增大会使传热恶化发生的位置提前,同时壁温飞升的数值更大。In order to ensure that the supercritical CFB boiler has good wide-load operation characteristics and the ability of deep peak regulation,the transient heat transfer characteristics between the working fluid and the water wall under the change of transcritical pressure are experimentally studied.Experiment adopted@25.0 mmx3.5 mm vertical upward tube,the near-critical steady heat transfer experiment and the transcritical pressure step transient heat transfer experiment were carried out under the experimental conditions of 20~23 MPa of pressure and 400~800 kg/(m^(2)·s)of mass flow rate.The results showed that under the near-critical pressure,increasing the flow rate,reducing the heat flux on the inner wall,and reducing the pressure can reduce the dryness when the DNB heat transfer deterioration occurs,and increase the corresponding fluid enthalpy value,and delay the occurrence of the heat transfer deterioration.When the transcritical pressure step changes,the heat transfer deterioration may occur in the heating pipe,resulting in the wall temperature rising rapidly,but the temperature will fall back to the normal value with the increase of the flow rate.The heat transfer between the wall temperature rising point and the inner wall surface goes through the heat transfer deterioration stage, the subcooled boiling heat transfer enhancementstage and the single liquid phase heat transfer stage. The influence of each parameter on the heat transferdeterioration in the transcritical pressure step change experiment is the same as that in the near-critical steady stateexperiment. The decrease of flow rate and the increase of heat flux on the inner wall will advance the location ofthe heat transfer deterioration, and the wall temperature rise will be greater.

关 键 词：CFB锅炉 深度调峰 跨临界动态特性 垂直上升管 传热恶化 

分 类 号：TM621.2[电气工程—电力系统及自动化]