摘要
建立了填充床熔盐蓄热器的热-力耦合数值模型,基于此模型,研究了多次蓄-放热循环下罐体壁面温度与应力的动态变化特性,并探讨了蓄热罐体产生高温蠕变与塑性屈服的失效区域。结果表明:单次蓄-放热循环中,①壁面温度呈4个阶段的变化趋势,即蓄热时的急剧温升与稳定阶段,放热时的缓慢温降与急剧下降阶段,且大部分罐壁均会产生蠕变现象;②筒节1~5的壁面处于低应力水平的弹性状态,壁板底端存在应力集中导致的塑性屈服现象,且峰值应力在蓄热时呈逐渐上升、放热时逐渐下降的变化趋势;多次蓄-放热循环中,①罐壁最高温度在631~836 K之间呈周期性变化,随着循环次数的增加,处于弹性状态的壁面在低应力与蠕变的作用下损伤累积,增加了蓄热器失效的风险;②内壁面峰值应力在275~423 MPa之间呈周期性变化,使得蓄热罐体可能会产生高应力(大于屈服强度)引起的低周疲劳断裂失效现象。本研究可为开展填充床蓄热器的动态应力疲劳寿命评估提供有效参考方法。
A coupled thermal stress integration model of the molten salt-packed-bed thermal storage tank is developed.The dynamic thermal and stress performances under various charging and discharging cycles are calculated using this model.High-temperature creep and plastic yield failure areas are also explored.For the single cycle,the results demonstrate that(1)there exist four variation tendencies of the tank wall temperature:sharply rise and stabilization stages in the charging process,gently decline and sharply decrease stages in the discharging process.Meanwhile,the creep phenomena would occur at the tank’s outermost portion.(2)The 1-5 shell section walls are in an elastic condition with lower stress levels,resulting in stress concentration at the bottom.Besides,the peak stress presents the first rise and then fall tendencies in the charging and discharging processes,respectively.(1)The highest temperature of the tank wall displays a cyclic fluctuation condition between 631 and836 K over the multiple cycles.Under the impact of decreased stress and creep,damage to the tank wall in the elastic condition would likely accrue,increasing the danger of tank failure.(2)Particularly,because the peak stress of the inner wall also varies in the period between 275and 423 MPa,the low-cycle fatigue fracture failure is induced by the high stress(greater than yield strength)that could occur during the charging and discharging cycles.This research might give a useful reference approach for determining the fatigue life of a packed bed tank under dynamic load.
作者
杜保存
黄丽娟
雷勇刚
宋翀芳
王飞
DU Baocun;HUANG Lijuan;LEI Yonggang;SONG Chongfang;WANG Fei(Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2022年第7期2141-2150,共10页
Energy Storage Science and Technology
基金
国家自然科学基金青年基金项目(51906172)。
关键词
太阳能热发电
熔盐
填充床蓄热器
蠕变
应力
concentrating solar power
molten salt
packed-bed thermal storage tank
creep
stress
