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为了青藏铁路多年冻土路基耦合热管优化设计的需要,建立多年冻土区天然地面耦合热管的相变传热模型,利用该模型研究不同热管管径、气候条件和冷凝段与蒸发段长度比对热管传冷量的影响。结果表明:大管径的热管对于提高热管的传冷量是有利的;在冷凝段与蒸发段长度比大于0.9的条件下,热管传冷量随长度比增大得并不明显,因此建议优化的冷凝段与蒸发段长度比取为稍大于0.9的值;与年平均气温较高的多年冻土区相比,年平均气温较低的多年冻土区更有利于热管的传冷。对比模型计算值和现场实验值表明,提出的模型与实际拟合良好。
In order to meet the need of optimization design of the coupled heat pipe for permafrost subgrade in Qinghai-Tibet Railway, a phase-change heat transfer model of natural ground-coupled heat pipe in permafrost region is established. The model is used to study the pipe diameter, climatic conditions and length ratio of condensing and evaporating sections Heat pipe cooling capacity. The results show that the heat pipe of large diameter is advantageous for increasing the heat transfer capacity of the heat pipe. Under the condition of the length ratio of the condensing section to the evaporating section is greater than 0.9, the heat transfer capacity of the heat pipe is not obvious with the length ratio increasing. The length ratio of condensing section to evaporator section is slightly larger than 0.9. Compared with the permafrost regions with higher annual average temperature, the permafrost regions with lower annual mean temperature are more conducive to heat pipe cooling. The comparison of the calculated values of the model and the field experiments show that the proposed model fits well with the actual situation.