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保温材料导热系数是衡量管道保温性能的重要参数之一,也是保温管道设计和管理中必不可少的基础数据。目前测定保温层导热系数的方法是取样快速导热系数测定仪测定,该方法会破坏保温材料测试表面的微观结构,因测试探头与试件之间存在接触热阻,测试结果误差较大,而且由于保温预制管发泡均匀程度不同,取样测试结果不能全面反映成型保温管道的整体保温效果。泡沫保温层整体导热系数测定法可以在不破坏保温层的情况下得到保温层整体平均导热系数,实验方法有两种:稳态法和瞬态法。由于稳态法有许多技术问题不好解决,故采用瞬态法,即静置温降法,具体方法是让温度恒定的液体在实验管段内流动,当温度场达到基本稳定时,停止流动,测量管内液体温度和夹克内壁温度,计算保温层整体导热系数。根据4次实验求得的整体导热系数平均值为0.039W/(m·℃),其值更接近部颁标准0.035W/(m·℃)。
Thermal conductivity of insulation materials is one of the important parameters of the pipe insulation performance, insulation pipe is also essential for the design and management of the basic data. At present, the method of determining the thermal conductivity of the thermal insulation layer is determined by a sample rapid thermal conductivity measuring instrument. This method destroys the microstructure of the test surface of the thermal insulation material. Because of the contact thermal resistance between the test probe and the test specimen, the test result has a large error, Insulation pre-tube foam uniform degree of different sampling test results can not fully reflect the molding insulation pipe insulation effect. Foam insulation overall thermal conductivity determination method can be obtained without undermining the insulation layer the average thermal conductivity of the overall average thermal conductivity, there are two experimental methods: steady-state method and transient method. The steady-state method has many technical problems not solved, so the transient method, that is, the static temperature drop method, the specific method is to make the temperature constant liquid flow in the experimental tube, when the temperature reaches a basic stable, stop the flow, Measure the temperature of the liquid in the tube and the jacket wall temperature to calculate the overall thermal conductivity of the insulation. According to 4 experiments, the average value of the overall thermal conductivity is 0.039W / (m · ℃), the value closer to the ministerial standard 0.035W / (m ℃).