Longitudinal scale effect of electro-thermal effectiveness of front panel of the integrated wooden electric heating composite based on carbon fiber paper
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摘要: 根据热力学能量守恒定律和傅里叶(Fourier)定律,利用一维传热理论推导基于碳纤维纸(CFP)的木质电热复合材料的结构特征与其表面空气温度效果之间的理论关系式,对其关系进行了定性分析,研究木质电热复合材料面层电热效果的纵向尺寸效应,分析表明面层板厚度与表面空气温度呈反比例关系。对面层板厚度分别为2 mm和4 mm的木质复合材料开展了温度测试试验,以验证理论计算结果正确性。结果显示,通过理论计算,得出基于CFP的木质电热复合材料面层厚度与表面空气温度之间呈反比关系;通过实验验证,对比两种不同面层材料厚度的电热复合材料表面空气温度,发现厚度为2 mm的电热复合材料表面空气温度高于厚度为4 mm的,与理论计算结果一致。在采暖领域,相对于面层板较厚的木质电热复合材料,面层板较薄的更能充分利用能源。Abstract: Based on laws of thermodynamics: law of conservation of energy and Fourier law, the theoretical relationship between the structure property and the environment temperature above the surface of the integrated wooden electric heating composites based on carbon fiber paper (CFP) was derived with the solution for one-dimensional heat transfer problem, and then qualitatively analyzed to study the longitudinal scale effect of the front panel of the integrated wooden electric heating composites. The derived relational expression shows an inversely proportional relationship between the structure property and the environment temperature. In order to verify the theoretical calculation results, the temperature tests were conducted on the integrated wooden electric heating composites with 2 mm and 4 mm thickness front panel respectively. The results show that the relationship between the thickness of the front panel and the air temperature above the surface of the composites based on CFP presents inversely proportion based on the mathematical calculation. Compared with the air temperature above the surface of composites with 4 mm thickness front panel, the air temperature of the composites with 2 mm thickness front panel turns out to be higher through experimental validation, which is consistent with the theoretical calculation. Hence, the integrated wooden electric heating composites with thinner front panel have an advantage of utilization of energy.
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Key words:
- carbon fiber paper /
- electro-thermal effect /
- electric heating composite /
- heat transfer /
- scale effect
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图 3 CFP木质电热复合材料传热过程示意图
Figure 3. Schematic representation of heat transfer of integrated wooden electric heating composites based on CFP
δ—Thickness of front panel; t1—Temperature of CFP; t2—Temperature of the front panel; t3 —Temperature of air; h—Surface coefficient of heat transfer; λ—Heat conductivity coefficient; A—Surface area of composite
表 1 CFP木质电热复合材料电气测试参数
Table 1. Electric parameters of integrated wooden electric heating composites based on CFP
Front panel thickness/mm Resistance/Ω Test voltage/V Actual power/kW 2 397 80 16.12 4 413 81.59 16.12 -
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