Abstract:

During the preparation process of the cold storage slurry,the crystal layer adheres and accumulates on the surface of the heat exchanger, which greatly worsens the heat transfer characteristics and reduces the system efficiency. It is found that when the binary eutectic solution is in the solid-liquid two-phase region, there is a micron level liquid film between the heat transfer surface and the crystal layer, which will significantly reduce the adhesion of the crystal layer. In this paper, the crystallization model of two components eutectic solution is put forward. With urea solution as the research object, the adhesion of crystal layer under different working conditions is tested by the crystallization and scour experiment. In the scour experiment of the crystal layer in the solid-liquid two-phase region urea solution, it is found that the crystal layer can be scoured and shedding under the suitable flow rate and supercooling degree. However, the crystalline layer with solid phase region can not be thoroughly washed away. The experiment shows that there is a positive correlation between supercooling and adhesion, and indirectly proves the existence of micro liquid film.

摘要：

蓄冷浆体制备过程中，晶层在换热器表面附着并积累，极大地恶化了传热特性，降低了系统效率。研究发现，当二元共晶溶液处于固液两相区时，传热面与晶层之间存在微米级液膜，会显著降低晶层的附着力。提出了二元共晶溶液的结晶模型，并以尿素溶液为研究对象，通过结晶冲刷实验检验了不同工况下的晶层的附着情况，对处于固液两相区的尿素溶液晶层的冲刷实验中，发现在适宜的流速和过冷度下，晶层可以被冲刷脱落。而在纯固相区的溶液晶层无法被彻底冲刷。实验证明了过冷度与附着力存在正相关，也间接证明了微液膜的存在。