【作者】 岳兰兰； 马其良；

【Author】 YUE Lan-lan, MA Qi-liang (College of Power Engineering, University of Shanghai for Science and Technology, shanghai 200093, China)

【机构】 上海理工大学动力工程学院；

【摘要】 用有限差分法对一台已在燃气锅炉尾部运行的冷凝换热装置的各排翅片管束的壁面温度进行了计算。结果表明,对于额定负荷的运行工况,仅有43．7％的管壁温度低于烟气的水露点,实现了对流与冷凝同时进行的复合传热,56．3％管壁温度高于水露点,仅有烟气对流换热而无凝结发生,计算结果与实验结果基本吻合。对于翅片式冷凝换热器,为充分利用其扩展表面凝结烟气中的水蒸汽,应尽可能使所有受热面壁温低于水露点,因此,对其壁温工况的研究不仅是必要的,而且是必须的。更多还原

【Abstract】 In this paper, the wall-temperature working state of each bank of finned tubes on a working condensing heat exchanger were calculated by finite element method, which was on a gas fired boiler end. With the rated load working state, the results indicated that only small part (43.7%) of wall temperature was lower than water dew-point temperature of the flue gas, and achieved composite heat transfer included convection and condensation; the major part (56.3%) was higher than water dew-point temperature of the flue gas, and only the flue gas heat convection happened. The compulational results was mainly accord to the experimental results. Then the author considered that, in order to make full use of extended surface of the finned tube condensing heat exchanger to condense the water vapour in the flue gas, it’s should to have wall temperature of all the heating surface below the water dew-point temperature. For this reason, it’s not only necessary but also must to make study on wall-temperature working-state.更多还原