冷凝式燃气热水器二次换热器数值模拟研究

发布时间：2019-02-25 12:58

【摘要】：二次换热器是冷凝式燃气热水器的重要部件,对提升燃气热水器的热效率具有关键作用。采用数值模拟的方法对冷凝式燃气热水器二次换热器进行研究,对实际设备进行合理简化,采用ANSYS ICEM CFD对几何模型进行网格划分,运用Fluent软件建立湍流模型和冷凝模型对二次换热器对流换热进行模拟。将实验测得的温度与模拟结果进行比较,验证模拟结果的准确性。通过对模拟结果的分析,找出二次换热器烟气流动和温度分布的规律,分析当前换热效果不理想的原因,提出3条改进措施:将烟气导流板从换热管束左侧移至中间位置,以改善烟气气流组织;增加一段导流板,使烟气进口与导流板连接,去除直角区域,以消除烟气气流在烟气进口侧上部的旋涡区;减少底部换热管束数量。
[Abstract]:Secondary heat exchanger is an important part of condensed gas water heater, which plays a key role in improving the thermal efficiency of gas water heater. The secondary heat exchanger of condensed gas water heater is studied by numerical simulation. The practical equipment is reasonably simplified and the geometric model is meshed by ANSYS ICEM CFD. The convection heat transfer of secondary heat exchanger was simulated by using Fluent software to establish turbulence model and condensation model. The temperature measured by the experiment is compared with the simulation results to verify the accuracy of the simulation results. Based on the analysis of simulation results, the rule of flue gas flow and temperature distribution in secondary heat exchanger is found out, and the reasons for the unsatisfactory heat transfer effect are analyzed. Three improvement measures are put forward: moving the flue gas diversion plate from the left side of the heat exchanger bundle to the middle position. To improve the flue gas distribution; By adding a section of diversion plate, the inlet of flue gas is connected with the plate to remove the right angle area, so as to eliminate the vortex zone of the flue gas flow in the upper part of the inlet side of the flue gas, and to reduce the number of heat transfer tubes at the bottom of the flue gas inlet.
【作者单位】：同济大学机械与能源工程学院;上海林内有限公司;
【分类号】：TU822

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