保温用天然生物质材料的热湿特性  

Thermal Conductivity and Moisture Absorption of Biomass Materials as Thermal Insulators

作　　者：IBRAHIMA CONTE 谢捷鸿[1] 徐杰[1] 彭晓峰[1] 

机构地区：[1]清华大学相变与界面现象实验室,北京100084

出　　处：《工业加热》2005年第3期1-4,共4页Industrial Heating

基　　金：国家自然科学基金资助项目(50136020)

摘　　要：实验分析一些廉价天然材料(椰壳和花生壳)的导热特性。利用同心球稳态测量方法测量确定椰壳和花生壳的导热系数,以及导热系数随温度的变化规律,同时以硅酸铝纤维材料为标准试样,与天然材料的导热性能进行对比分析。还对这些材料的低温吸湿作了初步测试,分析此类材料作为低温绝热材料的吸湿特性。研究结果表明,所有材料的导热系数均随温度的升高而增大,且增大速率都近似相等。影响天然生物质材料导热性质的因素主要有:纤维或多孔固体材料中的导热、孔隙中空气的对流换热,如果温度足够高的话,还有辐射换热。An experimental investigation is made to characterize thermal insulation properties of different natural and low cost materials (co- conut fibbers and groundnut coquets). A steady state method was used to perform calculation of thermal conductivity coefficient. For the purpose of comparison, the same procedure of experiment was done for aluminum silicate fibber. The result showed that for the all materials, thermal conductivity coefficient increases with temperature; and the increasing rates are very similar. The temperature dependence is due to the fact that at high temperatures, the energy transfer trough insulating materials may involve several modes: conduction through the fibrous or porous solid material; conduction through the air trapped in the void spaces; and, at sufficiently high temperatures, radiation. An ex- perimental setup was established to analyze the eventually moisture absorption by the insulating material when using at very low temperatures. The results showed that the water content within both coconut fiber and groundnut coquet increases with time, and higher water content was found at the coldest regions after 3 or 4 hours of testing time.

关 键 词：生物质 导热系数 热湿特性 

分 类 号：TM924.4[电气工程—电力电子与电力传动]