基于超材料的平板二维定向传热结构设计

基于变换热力学, 采用坐标斜变换和旋转变换得到定向传热结构单元的热导率分布表达式, 并利用隔热材料和铜分层排布实现了定向传热结构单元. 将定向传热结构单元周期性排列, 得到二维平板定向传热结构. 数值计算结果表明: 当外部热流流向该结构上表面时, 热量主要向两侧流动, 从而使上下表面保持低温. 与同厚度二氧化硅气凝胶隔热材料相比, 上表面温度降低33.3%, 下表面温度降低4.3%, 而侧面温度上升40.1%. 定向传热结构上表面温度的降低表明能够及时导走热量, 从而降低上表面的红外辐射; 下表面温度的降低说明定向传热结构比二氧化硅隔热材料具有更好的隔热效果; 上表面热量主要向两侧传输造成侧面温度急剧升高, 有利于热能的有效利用. 定向传热结构在红外隐身、热防护领域具有潜在的应用价值.

Design of two-dimensional plate directional heat transmission structure based on meta materials

Based on the transformation thermodynamics, the thermal conductivity expression for the unit cell of the directional heat transmission structure is derived by the oblique and rotary coordinate transformation. We obtain the two-dimensional plate directional heat transmission structure through periodically arranging the unit cells which are realized by layering copper and thermal insulation materials. The results from the numerical calculation indicate that the heat flux flows from the upper surface of the directional heat transmission structure to the two sides, while the upper and lower surface remain at low temperature. Compared with the temperature of SiO₂ aerogel thermal insulation material, the upper surface temperature falls 33.3%, the low surface temperature falls 4.3%, while the temperatures of the two sides rise 40.1%. The decrease of the upper surface temperature indicates that the heat on the upper surface can be guided timely, and then the infrared radiation can be weakened. The decrease of the lower surface temperature indicates that the adiabatic efficiency of the directional heat transmission structure is superior to that of the SiO₂ aerogel thermal insulation material. The heat transmission from the upper surface to the sides is conducive to the good use of the heat flux. The directional heat transmission has a potential application in the infrared stealth and heat protection.