Variation Law of Thermal Conductivity of Nonaqueous Reactive Polymer Thermal Insulation Materials Under Different Conditions in Tunnel
The frequency of high geo-temperature phenomenon gets higher,with the increase in the long and deep-buried tunnels of the new construction in China.Setting low thermal conductivity materials as thermal insulation layer has become one of effective target methods.However,the existing materials on heat transfer performance cannot satisfy the needs.As a kind of material,which could be used in tunnel heat insulation,the thermal conductivity of non-water reacted two-component polymer has rarely reported in detail.The project is based on the technique of transient plane source,the variation of the thermal conductivity of polymers under different conditions(ambient temperature,density and thickness)are tested and studied by HOTDISK instrument.The factors of weight distribution are affecting the thermal conductivity of polymers,which are analyzed by entropy method and comparison with traditional thermal insulation materials to verify the thermal insulation performance of polymer.The study reveals that the thermal conductivity of polymer firstly increases,and then decreases with temperatures.There are two rising sections(-40～10℃,20～90℃),one flat section(10～20℃)and one descending section(>90℃).The thermal conductivity of polymer increases with the increase of density.There is a phenomenon,which the density increases and the thermal conductivity decreases at high temperature.The thermal conductivity of polymer is independent of thickness.Among the factors affecting the thermal conductivity of polymer,the temperature has the greatest influence,the density is the second,and the thickness is the smallest.Polymer has excellent thermal insulation properties and can be popularized and applied as a thermal insulation material for high geo-temperature tunnels.
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