基于定形相变材料的相变砂浆热力学性能

Thermodynamic Performance of Phase Change Mortar Based on ShapeStabilized Phase Change Material

普通砂浆受温度差异影响时,常常会产生温度变形、温度应力和温度裂缝,而现有相变砂浆的低热导率易导致相变不充分、储能效率低等问题,导致其自我调温能力低,也难以更好地控制由温度引起的变形、应力及裂缝.采用石蜡基相变材料制备储能型砂浆,并通过优选导热增强剂的比表面积、厚度等材料物理参数,从材料本身来提高相变基体热导率和相变砂浆储能速率,从而提升其自调温性能.设计并搭建了材料热性能测试平台,测试相变砂浆的蓄热和热应变发展规律.结果表明,相变材料掺量30%的砂浆试块上表面温度比普通砂浆块温度降低9.7℃,热应变降低27.54%,表明该相变材料提高了蓄热能力并显著提升了砂浆的温度自调控性能.

Ordinary mortar often produces thermal deformation and cracks when it is applied.However,the low thermal conductivity of the existing phase change mortar easily leads to insufficient phase change and low energy storage efficiency,resulting in low thermal adaptability.Thus,it cannot effectively control the development of deformation,stress and fracture induced by temperature change.In this paper,paraffin-based phase change materials are used to prepare energy storage mortar,and by optimizing the three-dimensional microscopic parameters such as the specific surface area and thickness of the thermal conductivity enhancer,the focus is on improving the thermal conductivity of the phase change matrix and the energy storage rate of the phase change mortar,thereby improving its thermal adaptability.A thermal test platform was built to test its thermal performance including the energy storage and the thermal strain development with time.It is concluded that when the phase change matrix material was mixed with 30%,the surface temperature of the mortar block was lower by 9.7℃than that of the ordinary mortar block,and the thermal strain was reduced by 27.54%,indicating that the phase change material improved the heat storage efficiency and significantly improved its thermal properties of self-controlled temperature.