【摘要】 在一水平圆形加热表面上通过实验考察了饱和池核沸腾和过冷池核沸腾时 Ca CO3垢的生成对传热的影响。结果表明 ,在饱和池核沸腾和过冷池核沸腾的初始阶段沸腾传热系数均呈先降低后升高、达到一个最大值后稳定降低的趋势 ,而且在初始阶段出现了负污垢热阻现象。在相同操作条件下 ,过冷池核沸腾传热系数明显低于饱和池核沸腾传热系数。在分析污垢的生成和生长影响表面活化中心的基础上 ,对污垢的形成对沸腾传热的影响进行了机理分析。更多还原

【Abstract】 The effect of calcium carbonate scale formation on heat transfer of subcooled and saturated pool nucleate boiling was studied on a heated circular horizontal surface. The result shows that during both subcooled and saturated pool nucleate boiling the curve of the heat transfer coefficient measured versus time is characterized by a sharp decrease in heat transfer coefficient in the initiation period, followed by steep increase and then with a gradual decrease. Negative fouling resistance was found during the initial period. At exactly the same condition, the heat transfer coefficient of subcooled boiling is obviously lower than that of saturated boiling. The effect of scale deposition on nucleation centers on surface was analyzed, which has been used to explain the experimental results.更多还原