The Hot Disk thermal constant analyzer based on transient plane source technology is used to study the variation in ice thermal conductivity during the formation and melting. According to the system state

the ice formation and melting process can be divided into five stages

that is

the non-freezing process (pure water)

freezing process (ice-water mixture)

pure ice process

ice melting process (ice-water mixture)

and ice completely melted (pure water). On the basis of the experimental scheme

the temperature was first reduced from 10.3 ℃ to ?11.0 ℃ and then increased to 10.3 ℃. The measured thermal conductivities at these five stages were 0.592?0.669 W/(m?K)

0.603?2.284 W/(m?K)

2.019?3.106 W/(m?K)

0.611?1.945 W/(m?K)

and 0.596?0.598 W/(m?K). The results show that the system thermal conductivity varies dynamically during the process of water-ice phase change and the measured thermal conductivity may not be that of pure ice or ice-water mixture. During the ice formation process or ice melting process

the system thermal conductivity will suddenly vary

since the structure of water or ice may be changed when the temperature is near the freezing point. Due to the different densities of ice and water

the thermal conductivity of the system may be affected by the weak natural convection occurring in the local ice-water two-phase microenvironment. In the actual production activities

the formation and melting of ice generally occur successively

so the influence of the thermal imbalance on the biological environment or structural performance of the ice-related structures can be avoided if the dynamic change in thermal conductivity is taken into consideration.