PCM水泥胶囊相变储能控温防冻害研究

Research on PCM cement capsules phase change energy storage control and frost damage prevention

基于相变储能理论和传热学知识,将吸附石蜡的炉渣颗粒经水泥砂浆封装后制备成PCM水泥胶囊,铺设于基础回填土中进行相变控温。通过数值模拟方法,得到基础附近土体温度场,并提出外温传播梯度、温度等值线斜率和伞式控温半径3项控温评价指标。结果表明,铺设有PCM水泥胶囊层的回填土冷、热温的第1、第2传播梯度均大于原有土壤,温度传播衰减幅度较大;冷温温度等值线第2陡降段斜率远大于原有土壤,对冷温的伞式撑起效应显著,对热温不明显;冷、热温的伞式控温半径均大于原有土壤。综合3项指标可见,PCM水泥胶囊的相变控温作用对基础附近土体温度场产生了显著影响,可作为防止基础发生冻害的一种有效手段。

Based on the theory of phase change energy storage and the knowledge of heat transfer,the paraffin-adsorbed slag particles were encapsulated by cement mortar and prepared into PCM cement capsules,which were laid to the foundation backfill for phase change temperature control.By means of numerical simulation,the temperature field of soil near the foundation was obtained,and three temperature control evaluation indexes of external temperature propagation gradient,temperature isoline slope and umbrella temperature control radius,were extracted.The results showed that the first and second propagation gradients of PCM cement capsules backfill are larger than that of the original soil,and the temperature propagation attenuation range is larger.The slope of the second steep-fall section of cold temperature isoline is much higher than that of the original soil,and the umbrella-lift effect on cold temperature is significant,but not obvious to heat temperature.The umbrella-type temperature control radius is larger than that of the original soil.Based on the three indexes,it can be seen that temperature control effect of PCM cement capsules has a significant effect on the soil temperature field near the foundation,and it can be used as an effective means to prevent freezing damage of foundation.