聚合物添加剂对流动沸腾传热与减阻的研究

研究了两种不同相对分子质量 (2 5 6× 10 4 和 85 5× 10 4 )的聚合物添加剂聚丙烯酰胺 (简称PAM )在垂直铜管内对水的流动沸腾传热的强化情况 ,研究了添加剂水溶液浓度、质量流率、热通量等对流动沸腾传热的影响 ,根据测得的稀溶液在垂直铜管内流动沸腾的总压降 ,用Martinelli分离流模型求得了相应的摩擦压降。结果表明在低热通量下 ,在适当的浓度范围内 ,两种不同分子量的PAM不仅可提高流动沸腾传热系数 ,还可降低流动沸腾的阻力。研究还表明 ,在相同操作条件下 ,在同样质量浓度下 ,两种不同分子量的PAM对水流动沸腾具有较为相近的强化传热与减阻作用

Study on Heat Transfer and Drag Reduction in Flow Boiling of Polymer Additives

Using two kinds of polyacrylamide (PAM) in different molecular mass (256×10 4 and 855×10 4) to enhance the flow boiling heat transfer of water in vertical copper tube,effects of the additive aqueous concentration,mass flux,heat flux on flow boiling heat transfer were investigated.The friction pressure drop was calculated with Lockhart Martinelli model according to the total pressure drop measured in flow boiling of additive dilute solution.The results show that in low heat flux and at a suitable range of concentration,two kinds of PAM can increase the flow boiling heat transfer coefficient and decrease the flow drag of water.In addition,they have approximate enhancement of heat transfer and reduction of flow drag at the same mass concentration under the same operation condition.