摘要
超临界压力下,提出了余热锅炉直流蒸发器采用环形肋片管结构。采用回路划分法建立数学模型,计算直流蒸发器的传热系数,分析温度分布特性,并进行传热恶化判断。研究结果表明:随着工质焓值增加,直流蒸发器蒸汽侧传热系数先增大后减小,烟气侧传热系数不受影响,但烟气侧在换热系数中占主导地位;近拟临界焓值区,当工质温度高于拟临界温度,传热强化开始消失,内壁温度急剧增加;远离拟临界焓值区,处于低焓值区超临界水的换热强于高焓值区超临界汽;直流蒸发器管内工质均不发生传热恶化,同时在拟临界焓值区,存在传热强化。
Under supercritical pressure, the paper proposed that the once-through evaporator of the waste heat boiler adopts a ring-finned tube structure, adopted a loop division method, established a mathematical model, calculated the heat transfer coefficient of the once-through evaporator, analyzed the temperature distribution characteristics, and judged the deterioration of heat transfer. The research results show that as the working fluid enthalpy increases, the heat transfer coefficient on the steam side of the once-through evaporator first increases and then decreases, the heat transfer coefficient on the flue gas side is not affected, but the flue gas side is dominant in the heat transfer coefficient;Near the pseudo-critical enthalpy area, when the working fluid temperature is higher than the pseudo-critical temperature, the heat transfer enhancement begins to disappear, and the inner wall temperature increases sharply;far away from the pseudo-critical enthalpy area, the heat transfer of supercritical water in the low enthalpy area is stronger than the high enthalpy Supercritical steam in the value region;the working fluid in the once-through evaporator tube has no heat transfer deterioration, and at the same time, there is heat transfer enhancement in the pseudo-critical enthalpy region.
作者
赵子东
何海军
ZHAO Zi-dong;HE Hai-jun(不详)
出处
《节能》
2021年第1期28-32,共5页
Energy Conservation
关键词
直流蒸发器
传热系数
温度
拟临界
传热恶化
once-through evaporator
heat transfer coefficient
temperature
pseudo-critical
heat transfer deterioration
