池核沸腾传热强化及阻垢研究

ENHANCEMENT OF HEAT TRANSFERRING POOL NUCLEATE BOILING AND SCALE INHIBITING

通过池沸腾实验,利用自动数据采集系统考察了CaCO3的生成对饱和池核沸腾传热的影响,并考察添加剂和超疏水表面对池核沸腾传热的影响。选用W/O型聚丙烯酰胺(简称PAM)为添加剂,研究了添加剂水溶液的性质、添加剂浓度、热通量等因素对池核沸腾传热的影响,并对CaCO3的形成影响池核沸腾传热过程进行了机理分析,并以表面核化中心与污垢沉积及生长相互影响的观点对实验结果进行了解释。本实验通过动态模拟研究结果表明,W/O型聚丙烯酰胺具有强化池核沸腾传热的性能,PAM可降低气泡的脱离直径,增加气泡的脱离频率,提高传热系数,而且有最佳浓度范围;同时还表明经过超疏水处理后的加热器表面具有良好的抗垢性能,在稳定阶段,处理后的表面的传热系数高于未处理表面上的传热系数。

The effect of calcium carbonate scale formation and the heat transfer of saturated pool nucleate boiling was studied through auto-data system and pool boiling experiments. At the same time the additive polyarylamide (PAM) of W/O and the super hydrophobic surface effect were studied. With the additive-PAM the effect of characters of solution, concentration of additive, heat flux on the heat transferring pool nucleate boiling were studied. And the mechanism of the scale formation was analysed. The mechanism is also explained by the view that the surface nucleate center is affected by the deposition and growth of scale. The result through dynamic method show that PAM of W/O can enhance pool nucleate boiling heat transfer, it can decrease the diameter of the leaved bubble, increase the frequency of the leaved bubble so that it can enhance the heat transfer coefficient. And it has the best range of concentration. At the same time the heat reactor treated by super hydrophobic surface was proved to have good scale resistance, all the heat transfer coefficients of treated surface are higher than that of the untreated ones in the steady time.