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用瞬态法测定了使用不同年限的泡沫保温材料整管的导热系数,测定结果表明,随着使用时间的延长,保温材料结构收缩,导热系数增大。通过试验确定了双重保温管道环行空间自然对流换热在低Cr.Pr数下当量导热系数的计算公式。模拟计算表明,土壤当量导热系数的取值对管道的传热计算影响不大,给出了海底双重保温管道总传热系数的计算公式。
The thermal conductivity of the whole pipe with different length of foam insulation material was measured by transient method. The results showed that with the extension of service time, the thermal insulation material structure shrinks and the thermal conductivity increases. The formula of the equivalent thermal conductivity at low Cr.Pr of natural convection heat transfer in the circular space of the double insulated pipe was determined through experiments. The simulation results show that the value of soil equivalent thermal conductivity has little effect on the heat transfer calculation of the pipeline, and the formula for calculating the total heat transfer coefficient of the double insulated pipelines is given.