摘要
天然气锅炉的排烟温度一般在160～240℃，烟气中水蒸汽约占20％，它是烟气热量的主要携带者，若回收烟气余热，锅炉效率可大大提高。在回收余热过程中，由于凝结换热的存在，在不同换热截面上烟气侧换热系数及物性参数发生很大的变化，导致换热性能改变。利用传热传质理论对烟气倒换热进行研究，提出了新的换热系数计算方法。通过与实验值及文献数据的比较，获得满意的结果，为强化换热及设计出高效换热器提供了依据。
The temperature of exhaust gas of natural gas fired boilers generally lies between 160 ℃ - 240 ℃. The exhaust contains about 20 % water steam which carries away with it most of the heat in the flue gas. If this waste heat of the flue gas could be recovered, the boiler efficiency would markedly increase. In this case, due to the existence of heat exchange with condensation, heat transfer coefficients and the gas side＇ s physical parameters would vary from section to section, initiating changes in the heat transfer properties. After having studied the heat transfer at gas side with the help of heat and mass transfer theories, a new method of calculating the heat transfer coefficient is being presented. Comparison with test and bibliographical data shows this method to be satisfactory and may be useful for intensifying heat exchange and for designing heat exchangers of high efficiency. Figs 9 and refs 11.
出处
《动力工程》
EI
CAS
CSCD
北大核心
2006年第4期467-471,共5页
Power Engineering
基金
教育部重点实验室"电站设备状态监测与控制"项目资助
关键词
工程热物理
天然气锅炉
烟气换热
换热系数
传热
传质
余热回收
engineering thermophysics
natural gas fired boiler
flue gas heat transfer
heat transfer coefficient
heat transfer
mass transfer
waste heat recovery
