高温高压空气管道散热特性模拟分析

Simulation analysis of heat dissipation characteristics of high temperature and high pressure air pipeline

高温高压空气管道在运行工况的保温性能和工况转换的散热性能,是管道热工设计常需要考虑的问题.本研究以DN500高温高压空气管道为例,建立了以硅酸铝棉为保温材料的管道热工性能分析模型并进行了模拟研究.结果显示,管道正常运行时保温材料导热系数相差很大,管道内侧导热系数接近0.151 W/(m·K),是外侧的7.5倍.稳态工况管道散热量随保温层厚度增大而减小,且保温层厚度越大,厚度变化对管道散热量变化率影响越小.自然冷却工况下管道散热时间长,保温层厚度为200 mm的管道冷却至100℃需要10 d时间,而采用常温空气通入管道内强制冷却仅需要90 min.

The thermal insulation performance of high temperature and high pressure air pipeline under operating conditions and the heat dissipation characteristics of condition conversion are often considered in pipeline thermal design.In this study,taking DN500 high temperature and high pressure air pipeline as an example,the thermal performance analysis model of pipeline with aluminum silicate cotton as the insulation material was established and simulated.The results show that the thermal conductivity of the insulation material varies greatly during the normal operation of the pipeline.The thermal conductivity of the inside of the pipeline is close to 0.151 W/(m·K),which is 7.5 times that of the outside.In steady condition,the pipeline heat dissipation decreases with the increase of the insulating layer thickness,and the greater the insulating layer thickness,the smaller the influence of thickness change on the change rate of pipeline heat dissipation.The cooling time of the pipeline is long under natural cooling condition.It takes 10 days to cool the pipeline with 200 mm thickness of insulating layer to 100℃,while it only takes 90 minutes to cool the pipeline with normal temperature air.